In article ,
"DoN. Nichols" wrote:

On 2008-02-23, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-22, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-21, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-21, Joseph Gwinn wrote:


[ ... ]


That's what I normally do -- but I've got the largest insert
holder available to fit into my Aloris tool holders, and the inserts
which fit stop short of the acme thread which I had to cut to make a
replacement nut for a friend's leadscrew-driven log splitter. He
ordered a good bronze for the nut, and I made both a dummy external
thread to duplicate the one in the spitter, and then the internal thread
in the nut. For that -- it was a choice of grinding freehand, or using
the surface grinder, and the latter gave me more control of the
clearance angles to match them to the thread which I was cutting. The
external thread was cut with a standard 1/4" HSS bit held in the Aloris
holder, while the internal was a 3/16" bit held in an old boring bar
which fit one of the boring bar holders for the Aloris toolpost.

OK. What acme thread were you cutting? Given the delicate nature of
the application, one assumes that this leadscrew is quite dainty.

It was something like 1-1/4" diameter IIRC, and perhaps 5 or 6
TPI, I think.

Sounds plausible.


Shouldn't this been the excuse to buy a larger insert holder and insert?

Not an option. The shanks on large enough holders would not fit
in the toolpost holders on my lathe. I'm limited to 5/8" shanks. I
think that the next size up of inserts required 1" shanks, but I'm not
sure, and the MSC catalog is too deeply buried for me to dive into it at
the moment.

I would have thought that a 5/8 shank would suffice.

That's also the size of the slot in the lantern toolpost that comes with
the Clausing 5900 series lathes. I got the toolpost, but missing the
crescent-shaped rocker. This piece was lost some time ago, as I found a
rocker of the wrong curvature to fit the post, heavily marked where the
edges of the concave seat cut into the convex surface of the too-shallow
curvature of the rocker. I bought a used replacement, and it fits
better, but still not quite right. The real Clausing rocker is double
curved (being a toroidal surface, like the outside of a donut, it
appears), and hardened. The one I bought is cylindrical, not toroidal,
and matches only one curve, not both. (Does anyone have a spare of this
rocker?)

Joe Gwinn

On 2008-02-24, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-23, Joseph Gwinn wrote:

[ ... ]

OK. What acme thread were you cutting? Given the delicate nature of
the application, one assumes that this leadscrew is quite dainty.

It was something like 1-1/4" diameter IIRC, and perhaps 5 or 6
TPI, I think.

Sounds plausible.


Shouldn't this been the excuse to buy a larger insert holder and insert?

Not an option. The shanks on large enough holders would not fit
in the toolpost holders on my lathe. I'm limited to 5/8" shanks. I
think that the next size up of inserts required 1" shanks, but I'm not
sure, and the MSC catalog is too deeply buried for me to dive into it at
the moment.

I would have thought that a 5/8 shank would suffice.

Nope -- there were inserts in the pitch range, but only stub
Acme, not full Acme profile. The anvil needs to be enough bigger so the
head of the holder needs to be bigger too. And remember that what I
really had to make was an internal thread.

Another factor for thread cutting inserts is that there is not a
single anvil -- there is a range of them, each tilting the insert to one
side or the other by a specific angle to match the thread pitch angle
for the given diameter.

That's also the size of the slot in the lantern toolpost that comes with
the Clausing 5900 series lathes. I got the toolpost, but missing the
crescent-shaped rocker.

O.K. I wouldn't know, because mine came without a toolpost at
all. (And, I didn't miss it. :-) I had an old turret toolpost which I
could use while waiting for the Phase-II clone of the the Aloris BXA to
arrive, but I was very glad to retire it as soon as possible.

This piece was lost some time ago, as I found a
rocker of the wrong curvature to fit the post, heavily marked where the
edges of the concave seat cut into the convex surface of the too-shallow
curvature of the rocker. I bought a used replacement, and it fits
better, but still not quite right. The real Clausing rocker is double
curved (being a toroidal surface, like the outside of a donut, it
appears), and hardened. The one I bought is cylindrical, not toroidal,
and matches only one curve, not both. (Does anyone have a spare of this
rocker?)

Hmm ... sounds like you need to combine a radius turning tool
with a small toolpost grinder. Start with a collet-held fixture which
has a slot for the rocker-to-be, add setscrews tapped in from the side
to grip the blank rocker, then turn the end of the fixture to a sphere
of the proper radius. If necessary, stop with the radius just a little
long, remove the rocker-to-be, harden it and draw appropriately, then
put it back and use the toolpost grinder mod to the radius turning
fixture to take it to final dimensions. (I would suggest you rig some
kind of holder for a small air-driven die grinder, and mount it to serve
as the die grinder.)

Enjoy,
DoN.


--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-02-24, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-23, Joseph Gwinn wrote:

[ ... ]

OK. What acme thread were you cutting? Given the delicate nature of
the application, one assumes that this leadscrew is quite dainty.

It was something like 1-1/4" diameter IIRC, and perhaps 5 or 6
TPI, I think.

Sounds plausible.


Shouldn't this been the excuse to buy a larger insert holder and insert?

Not an option. The shanks on large enough holders would not fit
in the toolpost holders on my lathe. I'm limited to 5/8" shanks. I
think that the next size up of inserts required 1" shanks, but I'm not
sure, and the MSC catalog is too deeply buried for me to dive into it at
the moment.

I would have thought that a 5/8 shank would suffice.

Nope -- there were inserts in the pitch range, but only stub
Acme, not full Acme profile. The anvil needs to be enough bigger so the
head of the holder needs to be bigger too. And remember that what I
really had to make was an internal thread.

Another factor for thread cutting inserts is that there is not a
single anvil -- there is a range of them, each tilting the insert to one
side or the other by a specific angle to match the thread pitch angle
for the given diameter.

Clearly intended for large production of a specific thread, not a series
of one-off jobs.


That's also the size of the slot in the lantern toolpost that comes with
the Clausing 5900 series lathes. I got the toolpost, but missing the
crescent-shaped rocker.

O.K. I wouldn't know, because mine came without a toolpost at
all. (And, I didn't miss it. :-) I had an old turret toolpost which I
could use while waiting for the Phase-II clone of the the Aloris BXA to
arrive, but I was very glad to retire it as soon as possible.

My theory is that it is useful for use with big knurlers and the like,
which come up used for small dollars, and they don't fit Aloris B-series
toolholders.


This piece was lost some time ago, as I found a
rocker of the wrong curvature to fit the post, heavily marked where the
edges of the concave seat cut into the convex surface of the too-shallow
curvature of the rocker. I bought a used replacement, and it fits
better, but still not quite right. The real Clausing rocker is double
curved (being a toroidal surface, like the outside of a donut, it
appears), and hardened. The one I bought is cylindrical, not toroidal,
and matches only one curve, not both. (Does anyone have a spare of this
rocker?)

Hmm ... sounds like you need to combine a radius turning tool
with a small toolpost grinder. Start with a collet-held fixture which
has a slot for the rocker-to-be, add setscrews tapped in from the side
to grip the blank rocker, then turn the end of the fixture to a sphere
of the proper radius. If necessary, stop with the radius just a little
long, remove the rocker-to-be, harden it and draw appropriately, then
put it back and use the toolpost grinder mod to the radius turning
fixture to take it to final dimensions. (I would suggest you rig some
kind of holder for a small air-driven die grinder, and mount it to serve
as the die grinder.)

I've been thinking about this a bit. I think the easiest way is to hold
a piece of octagonal 5/8 thick plate in the 3-jaw chuck by means of a
large bored hole in the center, or bolt the octagonal 5/8 plate to the
dog driver plate, and machine the outer edge of the 5/8 plate to fit,
using a sphere-turning tool of some kind. When done, cut crescents from
the edge of the plate, and mill the sawn surface flat in the vertical
mill. Harden to taste. Given that one plate will yield multiple
rockers, hardening is probably not required.

Joe Gwinn

On 2008-02-25, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-24, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-23, Joseph Gwinn wrote:

[ ... ]

[ ... ]

Another factor for thread cutting inserts is that there is not a
single anvil -- there is a range of them, each tilting the insert to one
side or the other by a specific angle to match the thread pitch angle
for the given diameter.

Clearly intended for large production of a specific thread, not a series
of one-off jobs.

Actually -- for large production, you buy a full profile insert.
(Of course the Acme inserts are exactly that. :-) But for most
general-purpose threading, you buy inserts which are sharp V and don't
cut the thread crest, so one insert is usable for many pitches. The
angled anvils allow the insert to be ground with just enough clearance
for the task, without having to remove so much material that you weaken
the insert tip. This allows the same insert to be used for both
left-hand and right-hand threads, as well as being used for coarse
pitches on small diameters (steep angle) or fine pitches on large
diameters (very close to vertical angle).

As a hobbist, the only time I would buy a full-form thread
insert would be when I needed to do a production run for something where
the thread must have the rounded bottom to minimize stress risers. And
most of those I would cut with the Geometric die head anyway -- if it
did not need to be so long a threaded section that it would hit the center pivot rod for
the turret.

That's also the size of the slot in the lantern toolpost that comes with
the Clausing 5900 series lathes. I got the toolpost, but missing the
crescent-shaped rocker.

O.K. I wouldn't know, because mine came without a toolpost at
all. (And, I didn't miss it. :-) I had an old turret toolpost which I
could use while waiting for the Phase-II clone of the the Aloris BXA to
arrive, but I was very glad to retire it as soon as possible.

My theory is that it is useful for use with big knurlers and the like,
which come up used for small dollars, and they don't fit Aloris B-series
toolholders.

Even on the Clausing, I would use scissors style knurlers --
less wear on the cross-feed leadscrew if nothing else. I normally use
the BXA size knurling tool with two arms on a common vertical dovetail
and a left-and-right handed leadscrew to move the arms together and
apart in a balanced manner, so one height setting will work for all
sizes of knurls.

Of course, on the turret, I would use the T-style knurlers,
which also have two knurls pressing form opposite sides of the
workpiece.

[ ... ]

Hmm ... sounds like you need to combine a radius turning tool
with a small toolpost grinder. Start with a collet-held fixture which
has a slot for the rocker-to-be, add setscrews tapped in from the side
to grip the blank rocker, then turn the end of the fixture to a sphere
of the proper radius. If necessary, stop with the radius just a little
long, remove the rocker-to-be, harden it and draw appropriately, then
put it back and use the toolpost grinder mod to the radius turning
fixture to take it to final dimensions. (I would suggest you rig some
kind of holder for a small air-driven die grinder, and mount it to serve
as the die grinder.)

I've been thinking about this a bit. I think the easiest way is to hold
a piece of octagonal 5/8 thick plate in the 3-jaw chuck by means of a
large bored hole in the center, or bolt the octagonal 5/8 plate to the
dog driver plate, and machine the outer edge of the 5/8 plate to fit,
using a sphere-turning tool of some kind. When done, cut crescents from
the edge of the plate, and mill the sawn surface flat in the vertical
mill. Harden to taste. Given that one plate will yield multiple
rockers, hardening is probably not required.

Hmm ... that sounds interesting. But do you mean that you will
cut them as a partial torus around the hold-down bolt? I'm afraid that
won't produce the compound curve you need. Instead, turn a ball on the
end of a section of rod of perhaps 1-1/2" diameter or so (double the
measured radius of the ring), and then cut radial sections out of that.
On the horizontal mill, I would use a slitting saw and an index head
with a 3-jaw chuck to cut those. You could even set up two slitting
saws on an arbor with a spacer defining the width of the sector. I
might consider leaving the boring of the center hole until after the
sphere is turned and the slots cut.

Hmm ... is a Woodruff key made large enough? :-)

Also -- there is another trick for putting a spherical surface
on the end of a rod. Mount a boring head in the mill with the cutter
facing inwards instead of outwards. Then set up an index head at
something like a 45 degree angle, put the end under the center of the
boring head and start cranking the index head as you slowly bring down
the spindle with the boring head. Stop as the boring head is cutting a
circle around the center of the intended sphere. You can adjust the
size of the neck left by tuning the angle. I've seen this done to make
the ball-handle on a rifle bolt.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-02-25, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-24, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-23, Joseph Gwinn wrote:

[ ... ]

[ ... ]

Another factor for thread cutting inserts is that there is not a
single anvil -- there is a range of them, each tilting the insert to one
side or the other by a specific angle to match the thread pitch angle
for the given diameter.

Clearly intended for large production of a specific thread, not a series
of one-off jobs.

Actually -- for large production, you buy a full profile insert.
(Of course the Acme inserts are exactly that. :-) But for most
general-purpose threading, you buy inserts which are sharp V and don't
cut the thread crest, so one insert is usable for many pitches. The
angled anvils allow the insert to be ground with just enough clearance
for the task, without having to remove so much material that you weaken
the insert tip. This allows the same insert to be used for both
left-hand and right-hand threads, as well as being used for coarse
pitches on small diameters (steep angle) or fine pitches on large
diameters (very close to vertical angle).

Yes.


As a hobbist, the only time I would buy a full-form thread
insert would be when I needed to do a production run for something where
the thread must have the rounded bottom to minimize stress risers. And
most of those I would cut with the Geometric die head anyway -- if it
did not need to be so long a threaded section that it would hit the center
pivot rod for
the turret.

I don't really know what a "geometric die head" is. Can you suggest a
URL that leads to a drawing or photo?


That's also the size of the slot in the lantern toolpost that comes with
the Clausing 5900 series lathes. I got the toolpost, but missing the
crescent-shaped rocker.

O.K. I wouldn't know, because mine came without a toolpost at
all. (And, I didn't miss it. :-) I had an old turret toolpost which I
could use while waiting for the Phase-II clone of the the Aloris BXA to
arrive, but I was very glad to retire it as soon as possible.

My theory is that it is useful for use with big knurlers and the like,
which come up used for small dollars, and they don't fit Aloris B-series
toolholders.

Even on the Clausing, I would use scissors style knurlers --
less wear on the cross-feed leadscrew if nothing else. I normally use
the BXA size knurling tool with two arms on a common vertical dovetail
and a left-and-right handed leadscrew to move the arms together and
apart in a balanced manner, so one height setting will work for all
sizes of knurls.

Of course, on the turret, I would use the T-style knurlers,
which also have two knurls pressing form opposite sides of the
workpiece.

I don't think I will add much to the wear already experienced by the
Clausing in production use versus HSM use.


Hmm ... sounds like you need to combine a radius turning tool
with a small toolpost grinder. Start with a collet-held fixture which
has a slot for the rocker-to-be, add setscrews tapped in from the side
to grip the blank rocker, then turn the end of the fixture to a sphere
of the proper radius. If necessary, stop with the radius just a little
long, remove the rocker-to-be, harden it and draw appropriately, then
put it back and use the toolpost grinder mod to the radius turning
fixture to take it to final dimensions. (I would suggest you rig some
kind of holder for a small air-driven die grinder, and mount it to serve
as the die grinder.)

I've been thinking about this a bit. I think the easiest way is to hold
a piece of octagonal 5/8 thick plate in the 3-jaw chuck by means of a
large bored hole in the center, or bolt the octagonal 5/8 plate to the
dog driver plate, and machine the outer edge of the 5/8 plate to fit,
using a sphere-turning tool of some kind. When done, cut crescents from
the edge of the plate, and mill the sawn surface flat in the vertical
mill. Harden to taste. Given that one plate will yield multiple
rockers, hardening is probably not required.

Hmm ... that sounds interesting. But do you mean that you will
cut them as a partial torus around the hold-down bolt? I'm afraid that
won't produce the compound curve you need. Instead, turn a ball on the
end of a section of rod of perhaps 1-1/2" diameter or so (double the
measured radius of the ring), and then cut radial sections out of that.
On the horizontal mill, I would use a slitting saw and an index head
with a 3-jaw chuck to cut those. You could even set up two slitting
saws on an arbor with a spacer defining the width of the sector. I
might consider leaving the boring of the center hole until after the
sphere is turned and the slots cut.

I don't quite visualize your proposed approach.

Let me re-describe my approach. Take an octagonal or roughly circular
piece of steel plate 5/8" thick, and mount it firmly on the lathe such
that the rotation axis is perpendicular to the plane of the plate, and
more or less in the center of the piece.

This mounting may be accomplished in a number of ways. For instance,
one can bore a 2" diameter hole in the center, and use the 3-jaw chuck
with the jaws pressing firmly outward on the inside of this hole.

Machine the outer edge of this plate into a section of a torus. The
larger radius is about 3", and the smaller (thickness) radius is about
0.75", both measured by eyeball.

The reason to use a torus is to allow toolbars that are not perfectly
rectangular to nonetheless be clamped quite firmly.


Hmm ... is a Woodruff key made large enough? :-)

That would be quite the woodruff key. Seriously, the rocker is far
shallower in proportion than a woodruff key.


Also -- there is another trick for putting a spherical surface
on the end of a rod. Mount a boring head in the mill with the cutter
facing inwards instead of outwards. Then set up an index head at
something like a 45 degree angle, put the end under the center of the
boring head and start cranking the index head as you slowly bring down
the spindle with the boring head. Stop as the boring head is cutting a
circle around the center of the intended sphere. You can adjust the
size of the neck left by tuning the angle. I've seen this done to make
the ball-handle on a rifle bolt.

That is a classic sphere generator. I'm not so sure it can generate a
torus, as the intersection of a torus and a plane is not necessarily a
circle. I think it's an ellipse, as the in-plate and cross-plate radii
differ. If these radii were equal, the torus would be a sphere.

Joe Gwinn

On 2008-02-26, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

As a hobbist, the only time I would buy a full-form thread
insert would be when I needed to do a production run for something where
the thread must have the rounded bottom to minimize stress risers. And
most of those I would cut with the Geometric die head anyway -- if it
did not need to be so long a threaded section that it would hit the center
pivot rod for
the turret.

I don't really know what a "geometric die head" is. Can you suggest a
URL that leads to a drawing or photo?

O.K. I've found a URL which gives some images:

http://reno.craigslist.org/tls/563369567.html

but it is short on description, since it is simply someone selling a
used one, and it is presumed that the purchaser already knows what it is
and how to use it.

So -- I'll do the description here.

1) Picture something which looks like a 4-jaw chuck with strange
levers coming out radially.

2) Into the ways in the chuck fit four "chasers" -- chuck jaws
whose inner end is one quarter of a threading die. A full set is
sequentially numbered for which slot each one goes into to make
sure that the threads are continuations of each others. You
need a bin of chaser sets to cut different sized threads.

3) It is mounted to the lathe bed turret by the cylindrical
shank. This one has a 1-1/2" shank, while the largest which my
lathe turret will hold is 1".

4) You use the lever with the red ball handle to close the chasers
down to the proper diameter. This rotates part of the body to
close the chasers. Some Geometric die heads, like this one,
have a smaller lever which selects between roughing (a bit
oversized) and finish (to precise size). A pair of setscrews
(not visible in these photos) tune the final size of the thread
produced, so if you need a different fit class of thread, you
can achieve it.

5) With the workpiece spinning, you advance the turret to bring
the chasers into contact with the workpiece (which should start
out just a little oversized). Very soon, the chasers will bite,
and you simply need to follow the head as it is drawn onto the
workpiece. (I typically cut 5/8-27 threads in brass at 800 RPM
as an example, and with coolant in steel could cut just as fast.

6) Eventually, the turret ram reaches a preset stop, so the shank
of the die head stops, but the body and the chasers are drawn on
for a short bit more travel.

7) When it draws the right distance, it releases a lock pin and
releases the red-ball-handled lever and the collar to which it
is mounted to rotate, withdrawing the chasers radially so they
totally clear the OD of the workpiece.

8) At this point, you can withdraw the ram of the turret with the
workpiece still spinning at 800 RPM. When the turret ram
reaches its full back travel, it will rotate to bring a new
station and tool into position. However, if you are using the
rough/finish lever, you flip the lever from rough to finish and
use the red ball handle to close it again for another stroke.
(Without the rough/finish lever, you complete the whole thread
in a single stroke. And because the form of the chasers is
correct, you can simply check the setting by measuring the OD of
the finished thread, instead of having to use a thread pitch
micrometer, or a set of thread measuring wires.

The extra lever opposite the one with the red ball handle is
used by cam surfaces in an automatic screw machine so there is no need
for an operator to operate the handle. This lever, or the ball-handled
one, can be unscrewed if it is in the way.

Some models have a separate pin beside the body which can be set
to release the chasers by bumping into a surface beside the workpiece,
normally used for automatic screw machines as well.

Smaller die heads (I have down to 5/16", with 1" being my
largest) take less pull, so you want them for smaller threads so the
pull is not likely to strip the threads. You don't want to use a 1" die
head for an 0-80 thread for example.

the third photo shows the end of the die head with no chasers
installed. You can (barely) see the steep thread in the face inside
which moves the chasers in and out. The knurled knob at 2:00 (just
above the alternate lever for the Automatic Screw Machine) can be pulled
out while the lever is in the released position to allow the lever
to move just a bit more, bring an interruption in the threads into line,
so you can remove the chasers and replace them with a different set.

All in all, it is a very nice way to make a lot of threaded
objects in a batch.

There is also an inside-out version, called a "Collapsing Tap
Head" which can be used to make fairly large ID fine threads, such as
those used for making a set of extension tubes for a camera lens. I
have a couple of these just because -- not because I have a need for
them -- and I don't know what a set of chasers for that would cost. I
know that the normal chasers for the 5/16" die head are now about
$100.00 new. I've got four sizes of Geometric die heads:

5/16"
1/2" ***
3/4"
1"

*** I have never found chasers for this head -- I suspect that it is
totally obsolete.

[ ... ]

Even on the Clausing, I would use scissors style knurlers --
less wear on the cross-feed leadscrew if nothing else. I normally use
the BXA size knurling tool with two arms on a common vertical dovetail
and a left-and-right handed leadscrew to move the arms together and
apart in a balanced manner, so one height setting will work for all
sizes of knurls.

Of course, on the turret, I would use the T-style knurlers,
which also have two knurls pressing form opposite sides of the
workpiece.

I don't think I will add much to the wear already experienced by the
Clausing in production use versus HSM use.

Well ... the cross-slide leadscrew (which had been mostly used
under power feed for parting off) on my Clausing looked like this in
the middle:

__/\__/\__/\__/\__/\__/\__/\

instead of like this:
_ _ _ _ _ _ _
_/ \_/ \_/ \_/ \_/ \_/ \_/ \

thanks to long service. And that was a leadscrew which was just being
used for parting off. The lathe did not even have the threading dial
mounted, because it was being used with Geometric die heads in the
turret for threading.

[ ... ]

Hmm ... that sounds interesting. But do you mean that you will
cut them as a partial torus around the hold-down bolt? I'm afraid that
won't produce the compound curve you need. Instead, turn a ball on the
end of a section of rod of perhaps 1-1/2" diameter or so (double the
measured radius of the ring), and then cut radial sections out of that.
On the horizontal mill, I would use a slitting saw and an index head
with a 3-jaw chuck to cut those. You could even set up two slitting
saws on an arbor with a spacer defining the width of the sector. I
might consider leaving the boring of the center hole until after the
sphere is turned and the slots cut.

I don't quite visualize your proposed approach.

1) Make a ball on the end of a sufficient diameter rod to match the
radius of the ring around the lantern style toolpost.
Obviously, the ball can't be complete, but rather must have a
neck holding it to the chucked part of the workpiece.

2) Cut a series of slits into the ball from the OD towards
the center, but not reaching it. Ideally -- use two slitting
saws on a single arbor on the horizontal milling machine, so one
(if continued through the center) would be half the needed width
to one side of the center, and the other would be the same
distance to the other side, resulting in parts just the right
width.

3) Drill the center, and then bore out until you separate all of
the crescents from the main stock. Duck as they fly past your
head -- or catch them in a steel wire basket. :-)

Let me re-describe my approach. Take an octagonal or roughly circular
piece of steel plate 5/8" thick, and mount it firmly on the lathe such
that the rotation axis is perpendicular to the plane of the plate, and
more or less in the center of the piece.

This mounting may be accomplished in a number of ways. For instance,
one can bore a 2" diameter hole in the center, and use the 3-jaw chuck
with the jaws pressing firmly outward on the inside of this hole.

O.K. Your mention of mounting it to the faceplate did not show
the edge being totally clear of the faceplate, so I misinterpreted where
the contour was being cut. I was picturing a flat piece with one face
firmly against the faceplate, and the curve being cut on the other
something like this:
___
\
|
/
|
|
---+
-- Bolt here to center of faceplate -- perhaps a drawbar
through the faceplate and spindle
---+
|
|
\
|
____/

Machine the outer edge of this plate into a section of a torus. The
larger radius is about 3", and the smaller (thickness) radius is about
0.75", both measured by eyeball.

The reason to use a torus is to allow toolbars that are not perfectly
rectangular to nonetheless be clamped quite firmly.

Oh -- you want to relieve the center of the top of the crescent
so it contacts at the ends. I thought that you were trying to match the
compound curvature of the support ring around the toolpost. And that
would be difficult to do with anything other than a section of a sphere.

Note that the rockers which I have seen were forged, and have a
diamond pattern grip surface on the top.


Hmm ... is a Woodruff key made large enough? :-)

That would be quite the woodruff key. Seriously, the rocker is far
shallower in proportion than a woodruff key.

You cut off part of the Woodruff key. It just gets you closer
for a starting point.

I'm still using a lantern style toolpost -- but it is on my 7"
shaper, not on a lathe. And it does not have a rocker, but rather a
flat-topped support ring.

Also -- there is another trick for putting a spherical surface
on the end of a rod. Mount a boring head in the mill with the cutter
facing inwards instead of outwards. Then set up an index head at
something like a 45 degree angle, put the end under the center of the
boring head and start cranking the index head as you slowly bring down
the spindle with the boring head. Stop as the boring head is cutting a
circle around the center of the intended sphere. You can adjust the
size of the neck left by tuning the angle. I've seen this done to make
the ball-handle on a rifle bolt.

That is a classic sphere generator. I'm not so sure it can generate a
torus, as the intersection of a torus and a plane is not necessarily a
circle. I think it's an ellipse, as the in-plate and cross-plate radii
differ. If these radii were equal, the torus would be a sphere.

O.K. But I was trying to make a ball to cut into slices for a
proper match to the support ring curvature.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-02-26, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

As a hobbist, the only time I would buy a full-form thread
insert would be when I needed to do a production run for something where
the thread must have the rounded bottom to minimize stress risers. And
most of those I would cut with the Geometric die head anyway -- if it
did not need to be so long a threaded section that it would hit the center
pivot rod for
the turret.

I don't really know what a "geometric die head" is. Can you suggest a
URL that leads to a drawing or photo?

O.K. I've found a URL which gives some images:

http://reno.craigslist.org/tls/563369567.html

but it is short on description, since it is simply someone selling a
used one, and it is presumed that the purchaser already knows what it is
and how to use it.

The picture helped a lot.


So -- I'll do the description here.

1) Picture something which looks like a 4-jaw chuck with strange
levers coming out radially.

2) Into the ways in the chuck fit four "chasers" -- chuck jaws
whose inner end is one quarter of a threading die. A full set is
sequentially numbered for which slot each one goes into to make
sure that the threads are continuations of each others. You
need a bin of chaser sets to cut different sized threads.

3) It is mounted to the lathe bed turret by the cylindrical
shank. This one has a 1-1/2" shank, while the largest which my
lathe turret will hold is 1".

4) You use the lever with the red ball handle to close the chasers
down to the proper diameter. This rotates part of the body to
close the chasers. Some Geometric die heads, like this one,
have a smaller lever which selects between roughing (a bit
oversized) and finish (to precise size). A pair of setscrews
(not visible in these photos) tune the final size of the thread
produced, so if you need a different fit class of thread, you
can achieve it.

5) With the workpiece spinning, you advance the turret to bring
the chasers into contact with the workpiece (which should start
out just a little oversized). Very soon, the chasers will bite,
and you simply need to follow the head as it is drawn onto the
workpiece. (I typically cut 5/8-27 threads in brass at 800 RPM
as an example, and with coolant in steel could cut just as fast.

6) Eventually, the turret ram reaches a preset stop, so the shank
of the die head stops, but the body and the chasers are drawn on
for a short bit more travel.

7) When it draws the right distance, it releases a lock pin and
releases the red-ball-handled lever and the collar to which it
is mounted to rotate, withdrawing the chasers radially so they
totally clear the OD of the workpiece.

8) At this point, you can withdraw the ram of the turret with the
workpiece still spinning at 800 RPM. When the turret ram
reaches its full back travel, it will rotate to bring a new
station and tool into position. However, if you are using the
rough/finish lever, you flip the lever from rough to finish and
use the red ball handle to close it again for another stroke.
(Without the rough/finish lever, you complete the whole thread
in a single stroke. And because the form of the chasers is
correct, you can simply check the setting by measuring the OD of
the finished thread, instead of having to use a thread pitch
micrometer, or a set of thread measuring wires.

This sounds very useful in a production environment.


The extra lever opposite the one with the red ball handle is
used by cam surfaces in an automatic screw machine so there is no need
for an operator to operate the handle. This lever, or the ball-handled
one, can be unscrewed if it is in the way.

Some models have a separate pin beside the body which can be set
to release the chasers by bumping into a surface beside the workpiece,
normally used for automatic screw machines as well.

Smaller die heads (I have down to 5/16", with 1" being my
largest) take less pull, so you want them for smaller threads so the
pull is not likely to strip the threads. You don't want to use a 1" die
head for an 0-80 thread for example.

the third photo shows the end of the die head with no chasers
installed. You can (barely) see the steep thread in the face inside
which moves the chasers in and out. The knurled knob at 2:00 (just
above the alternate lever for the Automatic Screw Machine) can be pulled
out while the lever is in the released position to allow the lever
to move just a bit more, bring an interruption in the threads into line,
so you can remove the chasers and replace them with a different set.

All in all, it is a very nice way to make a lot of threaded
objects in a batch.

Yes. Think I'll hold off until I have a batch to do.


There is also an inside-out version, called a "Collapsing Tap
Head" which can be used to make fairly large ID fine threads, such as
those used for making a set of extension tubes for a camera lens. I
have a couple of these just because -- not because I have a need for
them -- and I don't know what a set of chasers for that would cost. I
know that the normal chasers for the 5/16" die head are now about
$100.00 new. I've got four sizes of Geometric die heads:

5/16"
1/2" ***
3/4"
1"

*** I have never found chasers for this head -- I suspect that it is
totally obsolete.

As I said, this would be a real asset in production.


Even on the Clausing, I would use scissors style knurlers --
less wear on the cross-feed leadscrew if nothing else. I normally use
the BXA size knurling tool with two arms on a common vertical dovetail
and a left-and-right handed leadscrew to move the arms together and
apart in a balanced manner, so one height setting will work for all
sizes of knurls.

Of course, on the turret, I would use the T-style knurlers,
which also have two knurls pressing form opposite sides of the
workpiece.

I don't think I will add much to the wear already experienced by the
Clausing in production use versus HSM use.

Well ... the cross-slide leadscrew (which had been mostly used
under power feed for parting off) on my Clausing looked like this in
the middle:

__/\__/\__/\__/\__/\__/\__/\

instead of like this:
_ _ _ _ _ _ _
_/ \_/ \_/ \_/ \_/ \_/ \_/ \

thanks to long service. And that was a leadscrew which was just being
used for parting off. The lathe did not even have the threading dial
mounted, because it was being used with Geometric die heads in the
turret for threading.

I assume that this crossfeed screw has been replaced by now. Mine
didn't look that bad, although the corresponding nut did seem a bit
loose. What kind of backlash is reasonable?


Hmm ... that sounds interesting. But do you mean that you will
cut them as a partial torus around the hold-down bolt? I'm afraid that
won't produce the compound curve you need. Instead, turn a ball on the
end of a section of rod of perhaps 1-1/2" diameter or so (double the
measured radius of the ring), and then cut radial sections out of that.
On the horizontal mill, I would use a slitting saw and an index head
with a 3-jaw chuck to cut those. You could even set up two slitting
saws on an arbor with a spacer defining the width of the sector. I
might consider leaving the boring of the center hole until after the
sphere is turned and the slots cut.

I don't quite visualize your proposed approach.

1) Make a ball on the end of a sufficient diameter rod to match the
radius of the ring around the lantern style toolpost.
Obviously, the ball can't be complete, but rather must have a
neck holding it to the chucked part of the workpiece.

2) Cut a series of slits into the ball from the OD towards
the center, but not reaching it. Ideally -- use two slitting
saws on a single arbor on the horizontal milling machine, so one
(if continued through the center) would be half the needed width
to one side of the center, and the other would be the same
distance to the other side, resulting in parts just the right
width.

3) Drill the center, and then bore out until you separate all of
the crescents from the main stock. Duck as they fly past your
head -- or catch them in a steel wire basket. :-)

Now I understand. This will yield a section of a sphere, not a torus.

That said, it would make mechanical sense if the surface were in fact a
sphere, not a torus. I will remeasure the two curvatures. It's hard to
measure the radius across the thickness, and I may have it wrong.


Let me re-describe my approach. Take an octagonal or roughly circular
piece of steel plate 5/8" thick, and mount it firmly on the lathe such
that the rotation axis is perpendicular to the plane of the plate, and
more or less in the center of the piece.

This mounting may be accomplished in a number of ways. For instance,
one can bore a 2" diameter hole in the center, and use the 3-jaw chuck
with the jaws pressing firmly outward on the inside of this hole.

O.K. Your mention of mounting it to the faceplate did not show
the edge being totally clear of the faceplate, so I misinterpreted where
the contour was being cut. I was picturing a flat piece with one face
firmly against the faceplate, and the curve being cut on the other
something like this:
___
\
|
/
|
|
---+
-- Bolt here to center of faceplate -- perhaps a drawbar
through the faceplate and spindle
---+
|
|
\
|
____/

Ahh. No. The plate edge would be out in space, well away from the
chuck.


Machine the outer edge of this plate into a section of a torus. The
larger radius is about 3", and the smaller (thickness) radius is about
0.75", both measured by eyeball.

The reason to use a torus is to allow toolbars that are not perfectly
rectangular to nonetheless be clamped quite firmly.

Oh -- you want to relieve the center of the top of the crescent
so it contacts at the ends. I thought that you were trying to match the
compound curvature of the support ring around the toolpost. And that
would be difficult to do with anything other than a section of a sphere.

Right. I'm wondering if it's a torus, or a sphere. A sphere would make
mechanical sense, and is easier to machine as well. Maybe I'll make a
disk out of thin aluminum, for fit testing.


Note that the rockers which I have seen were forged, and have a
diamond pattern grip surface on the top.

I have one of those. It almost fits, but is a cylinder, not a sphere or
torus. It is also hardened, making trimming arduous.


Hmm ... is a Woodruff key made large enough? :-)

That would be quite the woodruff key. Seriously, the rocker is far
shallower in proportion than a woodruff key.

You cut off part of the Woodruff key. It just gets you closer
for a starting point.

Except that the woodruff key is a cylinder, just like the forged rocker.


I'm still using a lantern style toolpost -- but it is on my 7"
shaper, not on a lathe. And it does not have a rocker, but rather a
flat-topped support ring.

No height adjustment needed.


Also -- there is another trick for putting a spherical surface
on the end of a rod. Mount a boring head in the mill with the cutter
facing inwards instead of outwards. Then set up an index head at
something like a 45 degree angle, put the end under the center of the
boring head and start cranking the index head as you slowly bring down
the spindle with the boring head. Stop as the boring head is cutting a
circle around the center of the intended sphere. You can adjust the
size of the neck left by tuning the angle. I've seen this done to make
the ball-handle on a rifle bolt.

That is a classic sphere generator. I'm not so sure it can generate a
torus, as the intersection of a torus and a plane is not necessarily a
circle. I think it's an ellipse, as the in-plate and cross-plate radii
differ. If these radii were equal, the torus would be a sphere.

O.K. But I was trying to make a ball to cut into slices for a
proper match to the support ring curvature.

Ok. It all depends on the true surface, sphere or torus. I will
revisit this.


Joe Gwinn

On 2008-02-28, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

O.K. I've found a URL which gives some images:

http://reno.craigslist.org/tls/563369567.html

but it is short on description, since it is simply someone selling a
used one, and it is presumed that the purchaser already knows what it is
and how to use it.

The picture helped a lot.

It does, typically. Even better is holding one in your hand. :-)


So -- I'll do the description here.

1) Picture something which looks like a 4-jaw chuck with strange
levers coming out radially.

[ ... ]

8) At this point, you can withdraw the ram of the turret with the
workpiece still spinning at 800 RPM. When the turret ram
reaches its full back travel, it will rotate to bring a new
station and tool into position. However, if you are using the
rough/finish lever, you flip the lever from rough to finish and
use the red ball handle to close it again for another stroke.
(Without the rough/finish lever, you complete the whole thread
in a single stroke. And because the form of the chasers is
correct, you can simply check the setting by measuring the OD of
the finished thread, instead of having to use a thread pitch
micrometer, or a set of thread measuring wires.

This sounds very useful in a production environment.

It is, indeed. Even a batch of 80 (from one 6' 3/4" brass rod)
counts as production enough to make it worthwhile. It is especially
nice for threading up to a shoulder, because once you preset the travel
stop on the ram for that particular station, you have no problems with
things shifting. The Shoulder is made by the previous station in the
turret, with a similar stop. A roller box tool is what is used for
that.

[ ... ]

All in all, it is a very nice way to make a lot of threaded
objects in a batch.

Yes. Think I'll hold off until I have a batch to do.

Beware that it took me about a year and a half haunting eBay to
find the three sizes which I use regularly, so there is something to be
said for getting it early. :-) I also found several lots of chasers for
the various sizes (everything but the 1/2" head) so most common threads
were easy to handle. I did buy two sets of chasers new. One for 5/8-27
(used in the 3/4" die head) and one for M2.5x0.45 (used in the 5/16" die
head. That one I had to special order, and it cost me about the same as
the 5/8-27 chasers from stock.

Note that there are fixtures for re-sharpening the chasers, and
there are specs for the proper rake for different materials. A coarse
thread, such as 3/8-16 in brass tends to chatter unless the rake is
right.

[ ... ]

5/16"
1/2" ***
3/4"
1"

*** I have never found chasers for this head -- I suspect that it is
totally obsolete.

As I said, this would be a real asset in production.

And -- you (ideally) need a bed turret for the lathe to make
most efficient use -- though you can fit it to a boring bar holder for a
quick-change toolpost if you take the time to properly center the bore
in the toolholder to the spindle axis. For that matter, you could
precede that with a roller box tool in another holder. Put a turret
carriage stop on the bed to stop each tool at the right place.

Hmm ... I wonder how repeatable the location of the boring bar
hole is from holder to holder. If you were going to use it that way, it
would be important.

I believe that I mentioned that the turret had 1" bores, which
was fine for the 3/4" and 1" die heads, and some other things, but I
also had to make adaptor collars for the 1/2" and 5/16" die heads, as
well as for some other tooling which was in the smaller size range.
(some to fit a tailstock turret -- six stations in a holder which mounts
via the Morse taper in the tailstock ram. But this has one major
disadvantage compared to the bed turret. It has no per-station travel
stops, so you have to measure as you crank the tailstock feed handwheel
each time.

[ ... ]

I don't think I will add much to the wear already experienced by the
Clausing in production use versus HSM use.

Well ... the cross-slide leadscrew (which had been mostly used
under power feed for parting off) on my Clausing looked like this in
the middle:

__/\__/\__/\__/\__/\__/\__/\

instead of like this:
_ _ _ _ _ _ _
_/ \_/ \_/ \_/ \_/ \_/ \_/ \

thanks to long service. And that was a leadscrew which was just being
used for parting off. The lathe did not even have the threading dial
mounted, because it was being used with Geometric die heads in the
turret for threading.

I assume that this crossfeed screw has been replaced by now.

Oh yes -- it was one of the first things to be replaced, along
with a broken pinion gear (one tooth broken off) in the turret,
resulting in a hitch in the feed. I got a new nut at the same time, of
course. But I got the leadscrew without the gear, and pressed on the
old gear from the previous one -- a significant difference in cost. :-)

Mine
didn't look that bad, although the corresponding nut did seem a bit
loose. What kind of backlash is reasonable?

Well ... that particular leadscrew had something like 0.070"
backlash, so it was obviously problematical. I would think that
anything under 0.005" would be very good for a used one, and probably up
to 0.015" would be acceptable.

[ ... ]

I don't quite visualize your proposed approach.

1) Make a ball on the end of a sufficient diameter rod to match the
radius of the ring around the lantern style toolpost.

[ ... ]

Now I understand. This will yield a section of a sphere, not a torus.

That is what I would expect to fit the ring. It should be a
section of a circle to allow the rocker to rock through full range of
adjustment.

That said, it would make mechanical sense if the surface were in fact a
sphere, not a torus. I will remeasure the two curvatures. It's hard to
measure the radius across the thickness, and I may have it wrong.

There may simply be small errors in the curvature turned in the
ring, and if there is any error, I would expect that the rocker should
make contact at the OD first. I wonder whether it was turned with a
form tool, or a radius turning tool.

[ ... ]

O.K. Your mention of mounting it to the faceplate did not show
the edge being totally clear of the faceplate, so I misinterpreted where

[ ... ]

Ahh. No. The plate edge would be out in space, well away from the
chuck.

O.K.

[ ... ]

The reason to use a torus is to allow toolbars that are not perfectly
rectangular to nonetheless be clamped quite firmly.

Oh -- you want to relieve the center of the top of the crescent
so it contacts at the ends. I thought that you were trying to match the
compound curvature of the support ring around the toolpost. And that
would be difficult to do with anything other than a section of a sphere.

Right. I'm wondering if it's a torus, or a sphere. A sphere would make
mechanical sense, and is easier to machine as well. Maybe I'll make a
disk out of thin aluminum, for fit testing.

O.K. No radius gauges in the proper size range? :-)

Note that the rockers which I have seen were forged, and have a
diamond pattern grip surface on the top.

I have one of those. It almost fits, but is a cylinder, not a sphere or
torus. It is also hardened, making trimming arduous.

Of course. I wonder whether the cylinder instead of the proper
curvature is intentional? That would cause the edges to dig into the
ring and make it less likely to slip sideways under cutting loads.


Hmm ... is a Woodruff key made large enough? :-)

That would be quite the woodruff key. Seriously, the rocker is far
shallower in proportion than a woodruff key.

You cut off part of the Woodruff key. It just gets you closer
for a starting point.

Except that the woodruff key is a cylinder, just like the forged rocker.

Which *may* be right. :-)


I'm still using a lantern style toolpost -- but it is on my 7"
shaper, not on a lathe. And it does not have a rocker, but rather a
flat-topped support ring.

No height adjustment needed.

Indeed -- and a stable rake angle helps, too.

[ ... ]

That is a classic sphere generator. I'm not so sure it can generate a
torus, as the intersection of a torus and a plane is not necessarily a
circle. I think it's an ellipse, as the in-plate and cross-plate radii
differ. If these radii were equal, the torus would be a sphere.

O.K. But I was trying to make a ball to cut into slices for a
proper match to the support ring curvature.

Ok. It all depends on the true surface, sphere or torus. I will
revisit this.

O.K.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-02-28, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

O.K. I've found a URL which gives some images:

http://reno.craigslist.org/tls/563369567.html

but it is short on description, since it is simply someone selling a
used one, and it is presumed that the purchaser already knows what it is
and how to use it.

The picture helped a lot.

It does, typically. Even better is holding one in your hand. :-)

Someday.


So -- I'll do the description here.

1) Picture something which looks like a 4-jaw chuck with strange
levers coming out radially.

[ ... ]

8) At this point, you can withdraw the ram of the turret with the
workpiece still spinning at 800 RPM. When the turret ram
reaches its full back travel, it will rotate to bring a new
station and tool into position. However, if you are using the
rough/finish lever, you flip the lever from rough to finish and
use the red ball handle to close it again for another stroke.
(Without the rough/finish lever, you complete the whole thread
in a single stroke. And because the form of the chasers is
correct, you can simply check the setting by measuring the OD of
the finished thread, instead of having to use a thread pitch
micrometer, or a set of thread measuring wires.

This sounds very useful in a production environment.

It is, indeed. Even a batch of 80 (from one 6' 3/4" brass rod)
counts as production enough to make it worthwhile. It is especially
nice for threading up to a shoulder, because once you preset the travel
stop on the ram for that particular station, you have no problems with
things shifting. The Shoulder is made by the previous station in the
turret, with a similar stop. A roller box tool is what is used for
that.

I'm still doing one and two, mostly for educational value.




As I said, this would be a real asset in production.

And -- you (ideally) need a bed turret for the lathe to make
most efficient use -- though you can fit it to a boring bar holder for a
quick-change toolpost if you take the time to properly center the bore
in the toolholder to the spindle axis. For that matter, you could
precede that with a roller box tool in another holder. Put a turret
carriage stop on the bed to stop each tool at the right place.

Hmm ... I wonder how repeatable the location of the boring bar
hole is from holder to holder. If you were going to use it that way, it
would be important.

The boring bar hole in various holders is probably pretty good, as
Aloris makes them on some kind if production line, but they make no
claim of repeatability between holders.


I don't think I will add much to the wear already experienced by the
Clausing in production use versus HSM use.

Well ... the cross-slide leadscrew (which had been mostly used
under power feed for parting off) on my Clausing looked like this in
the middle:

__/\__/\__/\__/\__/\__/\__/\

instead of like this:
_ _ _ _ _ _ _
_/ \_/ \_/ \_/ \_/ \_/ \_/ \

thanks to long service. And that was a leadscrew which was just being
used for parting off. The lathe did not even have the threading dial
mounted, because it was being used with Geometric die heads in the
turret for threading.

I assume that this crossfeed screw has been replaced by now.

Oh yes -- it was one of the first things to be replaced, along
with a broken pinion gear (one tooth broken off) in the turret,
resulting in a hitch in the feed. I got a new nut at the same time, of
course. But I got the leadscrew without the gear, and pressed on the
old gear from the previous one -- a significant difference in cost. :-)

Mine
didn't look that bad, although the corresponding nut did seem a bit
loose. What kind of backlash is reasonable?

Well ... that particular leadscrew had something like 0.070"
backlash, so it was obviously problematical. I would think that
anything under 0.005" would be very good for a used one, and probably up
to 0.015" would be acceptable.

Mine appears to have 0.048" of backlash, judged by turning the handle
and reading the dial drum.


I don't quite visualize your proposed approach.

1) Make a ball on the end of a sufficient diameter rod to match the
radius of the ring around the lantern style toolpost.

[ ... ]

Now I understand. This will yield a section of a sphere, not a torus.

That is what I would expect to fit the ring. It should be a
section of a circle to allow the rocker to rock through full range of
adjustment.

That said, it would make mechanical sense if the surface were in fact a
sphere, not a torus. I will remeasure the two curvatures. It's hard to
measure the radius across the thickness, and I may have it wrong.

There may simply be small errors in the curvature turned in the
ring, and if there is any error, I would expect that the rocker should
make contact at the OD first. I wonder whether it was turned with a
form tool, or a radius turning tool.

The slot appears to have been made by plunging a form cutter held in a
horizontal mill into the stock about 0.25".


The reason to use a torus is to allow toolbars that are not perfectly
rectangular to nonetheless be clamped quite firmly.

Oh -- you want to relieve the center of the top of the crescent
so it contacts at the ends. I thought that you were trying to match the
compound curvature of the support ring around the toolpost. And that
would be difficult to do with anything other than a section of a sphere.

Right. I'm wondering if it's a torus, or a sphere. A sphere would make
mechanical sense, and is easier to machine as well. Maybe I'll make a
disk out of thin aluminum, for fit testing.

O.K. No radius gauges in the proper size range? :-)

Not that big. Nor that narrow at the tip, to allow use at the bottom of
a narrow slot perpendicular to the slot.


Note that the rockers which I have seen were forged, and have a
diamond pattern grip surface on the top.

I have one of those. It almost fits, but is a cylinder, not a sphere or
torus. It is also hardened, making trimming arduous.

Of course. I wonder whether the cylinder instead of the proper
curvature is intentional? That would cause the edges to dig into the
ring and make it less likely to slip sideways under cutting loads.

I think that the cylinder is intentional for sure - the cylinder is
cheaper to make. With a section of a sphere, clamping is firm and
distributed over a broad area even if the bar being clamped isn't quite
rectangular. Which is why Clausing went to all that trouble.



Joe Gwinn

On 2008-03-02, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-28, Joseph Gwinn wrote:

[ ... ]

This sounds very useful in a production environment.

It is, indeed. Even a batch of 80 (from one 6' 3/4" brass rod)
counts as production enough to make it worthwhile. It is especially
nice for threading up to a shoulder, because once you preset the travel
stop on the ram for that particular station, you have no problems with
things shifting. The Shoulder is made by the previous station in the
turret, with a similar stop. A roller box tool is what is used for
that.

I'm still doing one and two, mostly for educational value.

Understood. When I got the lathe with the bed turret as part of
it (matching serial number) I had to get more tooling so I could use it
fully. I already had experience with various lathes from around that
size on down to tiny, but no turret experience. The turret came loaded
with three 1/2" Jacobs chucks and two floating reamer holders -- end of
list. :-)

[ ... ]

Hmm ... I wonder how repeatable the location of the boring bar
hole is from holder to holder. If you were going to use it that way, it
would be important.

The boring bar hole in various holders is probably pretty good, as
Aloris makes them on some kind if production line, but they make no
claim of repeatability between holders.

And if you mix manufacturers, the difference may be much
greater.

[ ... ]

didn't look that bad, although the corresponding nut did seem a bit
loose. What kind of backlash is reasonable?

Well ... that particular leadscrew had something like 0.070"
backlash, so it was obviously problematical. I would think that
anything under 0.005" would be very good for a used one, and probably up
to 0.015" would be acceptable.

Mine appears to have 0.048" of backlash, judged by turning the handle
and reading the dial drum.

O.K. Mine as a bit over 0.070" -- nearly 3/4 of a turn, and the
leadscrew was going to start wearing a lot faster.

Compare the backlash in the middle of travel to that at the ends
to see how much is in the leadscrew and how much is in the nut. If you
go to the point where the leadscrew is just barely fully in the nut you
should be measuring just the wear in the nut, since the leadscrew is
very seldom used in that range. And the more difference in backlash
between the ends and the middle, the more cumulative error in the dial
reading. I got both leadscrew and nut at the same time.

[ ... ]

There may simply be small errors in the curvature turned in the
ring, and if there is any error, I would expect that the rocker should
make contact at the OD first. I wonder whether it was turned with a
form tool, or a radius turning tool.

The slot appears to have been made by plunging a form cutter held in a
horizontal mill into the stock about 0.25".

Huh? I thought that we were talking about the curvature in the
ring which surrounds the lantern toolpost. That can be slipped over the
toolpost for measuring the radius with the toolpost out of the way.

[ ... ]

Right. I'm wondering if it's a torus, or a sphere. A sphere would make
mechanical sense, and is easier to machine as well. Maybe I'll make a
disk out of thin aluminum, for fit testing.

O.K. No radius gauges in the proper size range? :-)

Not that big. Nor that narrow at the tip, to allow use at the bottom of
a narrow slot perpendicular to the slot.

Again -- slip the ring off the top of the toolpost and measure
it free standing.

As for a tool to measure the radius -- try three rods on a set of
three collars which can allow the rods to both pivot and to slide back
and forth to set a radius. The extension of the rods which allows the
rods to pivot throughout the range of the curve and have all three
continue touching would be set to the true radius. I've seen such a
tool in an old Machist's toolbox.

Note that the rockers which I have seen were forged, and have a
diamond pattern grip surface on the top.

I have one of those. It almost fits, but is a cylinder, not a sphere or
torus. It is also hardened, making trimming arduous.

Of course. I wonder whether the cylinder instead of the proper
curvature is intentional? That would cause the edges to dig into the
ring and make it less likely to slip sideways under cutting loads.

I think that the cylinder is intentional for sure - the cylinder is
cheaper to make. With a section of a sphere, clamping is firm and
distributed over a broad area even if the bar being clamped isn't quite
rectangular. Which is why Clausing went to all that trouble.

Have you seen a true Clausing one to be sure that this was the
case? I don't think that Clausing made the toolposts for their lathes
-- they just bought from Armstrong. The parts are all forged, and it
makes more sense to get them from a vendor who is already set up to make
forged tools than to make one yourself for the machine in question.

But -- I wouldn't worry about it anyway. My Clausing came to me
without a lantern style toolpost, and I have been happy to keep it like
that. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-03-02, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-02-28, Joseph Gwinn wrote:

[ ... ]

This sounds very useful in a production environment.

It is, indeed. Even a batch of 80 (from one 6' 3/4" brass rod)
counts as production enough to make it worthwhile. It is especially
nice for threading up to a shoulder, because once you preset the travel
stop on the ram for that particular station, you have no problems with
things shifting. The Shoulder is made by the previous station in the
turret, with a similar stop. A roller box tool is what is used for
that.

I'm still doing one and two, mostly for educational value.

Understood. When I got the lathe with the bed turret as part of
it (matching serial number) I had to get more tooling so I could use it
fully. I already had experience with various lathes from around that
size on down to tiny, but no turret experience. The turret came loaded
with three 1/2" Jacobs chucks and two floating reamer holders -- end of
list. :-)

Well, no turret in my batch. But I'm liking Aloris better and better.


Hmm ... I wonder how repeatable the location of the boring bar
hole is from holder to holder. If you were going to use it that way, it
would be important.

The boring bar hole in various holders is probably pretty good, as
Aloris makes them on some kind if production line, but they make no
claim of repeatability between holders.

And if you mix manufacturers, the difference may be much
greater.

Yep.


didn't look that bad, although the corresponding nut did seem a bit
loose. What kind of backlash is reasonable?

Well ... that particular leadscrew had something like 0.070"
backlash, so it was obviously problematical. I would think that
anything under 0.005" would be very good for a used one, and probably up
to 0.015" would be acceptable.

Mine appears to have 0.048" of backlash, judged by turning the handle
and reading the dial drum.

O.K. Mine as a bit over 0.070" -- nearly 3/4 of a turn, and the
leadscrew was going to start wearing a lot faster.

Much worse.


Compare the backlash in the middle of travel to that at the ends
to see how much is in the leadscrew and how much is in the nut. If you
go to the point where the leadscrew is just barely fully in the nut you
should be measuring just the wear in the nut, since the leadscrew is
very seldom used in that range. And the more difference in backlash
between the ends and the middle, the more cumulative error in the dial
reading. I got both leadscrew and nut at the same time.

It's 0.055" at one end and 0.040 at the other, and the dovetail gets
looser at one ned versus the other.

Most of the problem seems to be in the nut. Maybe I'll make a new nut.
It was pretty simply shaped, and an Acme tap set is probably cheaper
than a new nut from Clausing. It's $48.50.


There may simply be small errors in the curvature turned in the
ring, and if there is any error, I would expect that the rocker should
make contact at the OD first. I wonder whether it was turned with a
form tool, or a radius turning tool.

The slot appears to have been made by plunging a form cutter held in a
horizontal mill into the stock about 0.25".

Huh? I thought that we were talking about the curvature in the
ring which surrounds the lantern toolpost. That can be slipped over the
toolpost for measuring the radius with the toolpost out of the way.

I don't see any Armstrong markings.

The part I'm talking about above is a very thick washer (Tool Post
Washer, C-375) that fits over the toolpost, and having a shallow slot
milled into one face to accept the rocker (Tool Post Wedge, C-378). The
bottom of the slot appears to be spherical.

Interestingly, the drawing (page 30) in the Clausing 5914 manual shows a
washer with a full spherical seat on one side, versus a slot, so the
slotted washer was probably a later design. The slotted washer is
probably easier to make, and stronger.


Right. I'm wondering if it's a torus, or a sphere. A sphere would make
mechanical sense, and is easier to machine as well. Maybe I'll make a
disk out of thin aluminum, for fit testing.

O.K. No radius gauges in the proper size range? :-)

Not that big. Nor that narrow at the tip, to allow use at the bottom of
a narrow slot perpendicular to the slot.

Again -- slip the ring off the top of the toolpost and measure
it free standing.

Getting the ring off the toolpost isn't the problem. It's the
restricted access to the bottom of the slot.


As for a tool to measure the radius -- try three rods on a set of
three collars which can allow the rods to both pivot and to slide back
and forth to set a radius. The extension of the rods which allows the
rods to pivot throughout the range of the curve and have all three
continue touching would be set to the true radius. I've seen such a
tool in an old Machinist's toolbox.

I'm not visualizing this.


Note that the rockers which I have seen were forged, and have a
diamond pattern grip surface on the top.

I have one of those. It almost fits, but is a cylinder, not a sphere or
torus. It is also hardened, making trimming arduous.

Of course. I wonder whether the cylinder instead of the proper
curvature is intentional? That would cause the edges to dig into the
ring and make it less likely to slip sideways under cutting loads.

I think that the cylinder is intentional for sure - the cylinder is
cheaper to make. With a section of a sphere, clamping is firm and
distributed over a broad area even if the bar being clamped isn't quite
rectangular. Which is why Clausing went to all that trouble.

Have you seen a true Clausing one to be sure that this was the
case? I don't think that Clausing made the toolposts for their lathes
-- they just bought from Armstrong. The parts are all forged, and it
makes more sense to get them from a vendor who is already set up to make
forged tools than to make one yourself for the machine in question.

I have no way to know if what I have is true Clausing. What I have was
machined, not forged, and lacks Armstrong markings. Although the rocker
could have been forged. Or forged then machined. Not having the
rocker, it's hard to say.


But -- I wouldn't worry about it anyway. My Clausing came to me
without a lantern style toolpost, and I have been happy to keep it like
that. :-)

My reason is that lantern toolpost tooling does come up used around
here, and it's worthwhile to be able to use it, as it often goes begging.


Joe Gwinn

On 2008-03-05, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:


[ ... ]

Understood. When I got the lathe with the bed turret as part of
it (matching serial number) I had to get more tooling so I could use it
fully. I already had experience with various lathes from around that
size on down to tiny, but no turret experience. The turret came loaded
with three 1/2" Jacobs chucks and two floating reamer holders -- end of
list. :-)

Well, no turret in my batch. But I'm liking Aloris better and better.

You might find a turret on eBay -- I've seen them for sale from
time to time. But it won't be a matching serial number. :-) I believe
that I pointed you to a PDF scan of the manual (very faded
third-generation Xerox copy), and from that you can get several possible
part numbers -- all were interchangeable, apparently.

[ ... ]

The boring bar hole in various holders is probably pretty good, as
Aloris makes them on some kind if production line, but they make no
claim of repeatability between holders.

And if you mix manufacturers, the difference may be much
greater.

Yep.

And since some of my tooling is always purchased used, there may
have been changes in Aloris' dimensions over the years, too.

[ ... ]

Mine appears to have 0.048" of backlash, judged by turning the handle
and reading the dial drum.

O.K. Mine as a bit over 0.070" -- nearly 3/4 of a turn, and the
leadscrew was going to start wearing a lot faster.

Much worse.

Agreed. Both the leadscrew and the nut were really badly worn.


Compare the backlash in the middle of travel to that at the ends
to see how much is in the leadscrew and how much is in the nut. If you
go to the point where the leadscrew is just barely fully in the nut you
should be measuring just the wear in the nut, since the leadscrew is
very seldom used in that range. And the more difference in backlash
between the ends and the middle, the more cumulative error in the dial
reading. I got both leadscrew and nut at the same time.

It's 0.055" at one end and 0.040 at the other, and the dovetail gets
looser at one ned versus the other.

O.K. I think that you should replace the leadscrew at the same
time as the nut, then.

Most of the problem seems to be in the nut. Maybe I'll make a new nut.
It was pretty simply shaped, and an Acme tap set is probably cheaper
than a new nut from Clausing. It's $48.50.

First thing to be careful about. The thread is 1/2-10 Acme
*LH*, and all of the combination roughing/finishing Acme taps have been
right-hand only. I did get a left-hand Acme tap of the right thread,
but IIRC it cost nearly as much as the nut at that time.

What does your nut look like? Mine looks like a plumbing Tee,
with the Acme thread through the two straight sides, and the upright of
the 'T' turned for a certain length and then a shoulder left to keep the
Acme thread's centerline the right distance below the cross-slide.
There is a hole drilled through the upright, with a spring-loaded ball
oiling point in the center so you can get oil to the leadscrew and nut
easily (after sweeping off lots of chips, of course. :-) This is one
reason why I normally keep the taper attachment unmounted. The Nut
looks like an over-tall Quonset hut of bronze brazed to a 'U' of 1/4"
square steel, and it is allowed to slide back and forth when the taper
attachment sides. This means that it is more difficult to get oil to
the leadscrew and especially into the nut.

Some of these days I'll get a chunk of bronze of adequate size
and use it to make a new nut. Then I'll make a matching leadscrew so I
am ready for the next time it wears out. :-) And -- this will give me
practice in making spare leadscrews and nuts for the taper attachment
too, so if the taper attachment wears fast, I can swap back in a normal
nut and leadscrew. (Actually -- the leadscrew is identical for both
the standard cross slide and my taper attachment -- but not for the
fancier taper attachment with the telescoping leadscrew.

There may simply be small errors in the curvature turned in the
ring, and if there is any error, I would expect that the rocker should
make contact at the OD first. I wonder whether it was turned with a
form tool, or a radius turning tool.

The slot appears to have been made by plunging a form cutter held in a
horizontal mill into the stock about 0.25".

Huh? I thought that we were talking about the curvature in the
ring which surrounds the lantern toolpost. That can be slipped over the
toolpost for measuring the radius with the toolpost out of the way.

I don't see any Armstrong markings.

O.K.

The part I'm talking about above is a very thick washer (Tool Post
Washer, C-375) that fits over the toolpost, and having a shallow slot
milled into one face to accept the rocker (Tool Post Wedge, C-378). The
bottom of the slot appears to be spherical.

Interestingly, the drawing (page 30) in the Clausing 5914 manual shows a
washer with a full spherical seat on one side, versus a slot, so the
slotted washer was probably a later design. The slotted washer is
probably easier to make, and stronger.

Aha! It suddenly makes sense what you have been saying. i've
only ever seen the ones with the full spherical relief on the washer.

[ ... ]

O.K. No radius gauges in the proper size range? :-)

Not that big. Nor that narrow at the tip, to allow use at the bottom of
a narrow slot perpendicular to the slot.

Again -- slip the ring off the top of the toolpost and measure
it free standing.

Getting the ring off the toolpost isn't the problem. It's the
restricted access to the bottom of the slot.

Which I never saw.

But to my mind it would *have* to be a conical section at least
to handle the motion of the rocker.


As for a tool to measure the radius -- try three rods on a set of
three collars which can allow the rods to both pivot and to slide back
and forth to set a radius. The extension of the rods which allows the
rods to pivot throughout the range of the curve and have all three
continue touching would be set to the true radius. I've seen such a
tool in an old Machinist's toolbox.

I'm not visualizing this.

It doesn't matter, though this would still work even with your
slotted washer instead of the turned washer.

I can't really do a full ASCII drawing, but pictu
_
| |
||||||||||||||| --- knurled nut
+-------+
| |
| 0 |1
| |
+-------+
+-------+
| |
| 0 |2
| |
+-------+
+-------+
| |
| 0 |3
| |
+-------+
||||||||||||||| --- knurled nut
|_|


a) Now -- part (2) there has a threaded shaft projecting from each
end through (1) and (3)

b) The holes, (shown as '0' in each part) are off center enough to
clear the threaded shafts passing through parts (1) and (3).

c) Not shown -- small thumbscrews to lock shafts into the holes.
Loosen them and the shafts slide, tighten them and the shafts
are locked in place.

d) The shaft in (2) is straight, coming to a point.

e) The shafts in (1) and (3) are straight except at the end where
they are bent in to almost touch the tip of the shaft in (2).

f) If you adjust the shafts so the tips are the same distance from
the centerline of the assembly above, then loosen the knurled
nuts and pivot each to they are forming something like "|",
all three points will touch on a curve of a radius which matches
the distance of the tips from the centerline. If the radius is
larger or smaller, only two of the tips will touch.

g) So -- the trick is how to measure the radius of the tip from the
center. For that, you will have to design and make your own
fixture. I've "designed" the tool. :-)

h) Note that the holes in (b) above *could* be on center if the
studs are large enough to accept a through hole with a
countersink bevel on each side -- though this would limit the
swiveling of the rods to something like +/- 45 degrees or so.

[ ... ]

I think that the cylinder is intentional for sure - the cylinder is
cheaper to make. With a section of a sphere, clamping is firm and
distributed over a broad area even if the bar being clamped isn't quite
rectangular. Which is why Clausing went to all that trouble.

Have you seen a true Clausing one to be sure that this was the
case? I don't think that Clausing made the toolposts for their lathes
-- they just bought from Armstrong. The parts are all forged, and it
makes more sense to get them from a vendor who is already set up to make
forged tools than to make one yourself for the machine in question.

I have no way to know if what I have is true Clausing. What I have was
machined, not forged, and lacks Armstrong markings. Although the rocker
could have been forged. Or forged then machined. Not having the
rocker, it's hard to say.

It may be a shop-made replacement.

But -- I wouldn't worry about it anyway. My Clausing came to me
without a lantern style toolpost, and I have been happy to keep it like
that. :-)

My reason is that lantern toolpost tooling does come up used around
here, and it's worthwhile to be able to use it, as it often goes begging.

Well ... I have lantern toolpost and holders for the 6x16"
Atlas/Craftsman -- but I also don't *use* that lathe any more. it was
in pretty bad shape when I first got it -- including some hacksaw
notches in the bed, and significant bed wear near the chucks. It also
had two chucks which were obviously made for the 10" or 12" Atlas, and a
threaded bushing to adapt the two of them to the spindle of the 6x18. :-)
This hastened wear on the spindle bearings (bushings, not roller as in
the later ones).

But it did help me for quite a while until I got better
machines. If I were to use it today, I would make a quick-change
toolpost (of some sort) for it -- or try one of the smaller ones sold to
the hobby crowd.

As it is -- the last significant metalwork related to it was
making something *for* it instead of *with* it. A parting tool hung up
and split off half of the T-slot in the compound top slide, so I had to
make a replacement of good tool steel, instead of the original cast
iron. More recently, I spent some time with the surface grinder turning
the milling spirals on the surface into a nicer finish.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-03-05, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:


[ ... ]

Understood. When I got the lathe with the bed turret as part of
it (matching serial number) I had to get more tooling so I could use it
fully. I already had experience with various lathes from around that
size on down to tiny, but no turret experience. The turret came loaded
with three 1/2" Jacobs chucks and two floating reamer holders -- end of
list. :-)

Well, no turret in my batch. But I'm liking Aloris better and better.

You might find a turret on eBay -- I've seen them for sale from
time to time. But it won't be a matching serial number. :-) I believe
that I pointed you to a PDF scan of the manual (very faded
third-generation Xerox copy), and from that you can get several possible
part numbers -- all were interchangeable, apparently.

The implication being that one assembles a full turret from parts
acquired one by one on eBay?

Actually, a taper attachment is higher on my list. I did see a
telescoping taper attachment for a Clausing lathe other than 5900 series
listed on eBay yesterday, but gone today. Taper attachments are
model-specific, so I didn't pay much attention.


The boring bar hole in various holders is probably pretty good, as
Aloris makes them on some kind if production line, but they make no
claim of repeatability between holders.

And if you mix manufacturers, the difference may be much
greater.

Yep.

And since some of my tooling is always purchased used, there may
have been changes in Aloris' dimensions over the years, too.

I bet that Aloris keeps them pretty accurate, so their industrial
customers don't yell at them.

Given that the Aloris-type toolposts and toolholders are
interchangeable, and acknowledged as such in the Aloris catalog, I bet
that Aloris has shared the critical drawings with their competitors, the
probable intent being to make the pie bigger for all. I would guess
that this happened as the expiration of the key patents loomed.

Toolpost, original: 2,972,272

Toolpost, indexable: 6,230,595

Cut-off tool: 3,455,001

Holder for triangle inserts: 3,280,450


Mine appears to have 0.048" of backlash, judged by turning the handle
and reading the dial drum.

O.K. Mine as a bit over 0.070" -- nearly 3/4 of a turn, and the
leadscrew was going to start wearing a lot faster.

Much worse.

Agreed. Both the leadscrew and the nut were really badly worn.


Compare the backlash in the middle of travel to that at the ends
to see how much is in the leadscrew and how much is in the nut. If you
go to the point where the leadscrew is just barely fully in the nut you
should be measuring just the wear in the nut, since the leadscrew is
very seldom used in that range. And the more difference in backlash
between the ends and the middle, the more cumulative error in the dial
reading. I got both leadscrew and nut at the same time.

It's 0.055" at one end and 0.040 at the other, and the dovetail gets
looser at one ned versus the other.

O.K. I think that you should replace the leadscrew at the same
time as the nut, then.

Yes.


Most of the problem seems to be in the nut. Maybe I'll make a new nut.
It was pretty simply shaped, and an Acme tap set is probably cheaper
than a new nut from Clausing. It's $48.50.

First thing to be careful about. The thread is 1/2-10 Acme
*LH*, and all of the combination roughing/finishing Acme taps have been
right-hand only. I did get a left-hand Acme tap of the right thread,
but IIRC it cost nearly as much as the nut at that time.

Hmm. Cut on the lathe?


What does your nut look like? Mine looks like a plumbing Tee,
with the Acme thread through the two straight sides, and the upright of
the 'T' turned for a certain length and then a shoulder left to keep the
Acme thread's centerline the right distance below the cross-slide.
There is a hole drilled through the upright, with a spring-loaded ball
oiling point in the center so you can get oil to the leadscrew and nut
easily (after sweeping off lots of chips, of course. :-) This is one
reason why I normally keep the taper attachment unmounted. The Nut
looks like an over-tall Quonset hut of bronze brazed to a 'U' of 1/4"
square steel, and it is allowed to slide back and forth when the taper
attachment sides. This means that it is more difficult to get oil to
the leadscrew and especially into the nut.

The nut I'm talking about is a cylinder with the threaded hole
crosswise. It is part number DL-471 (Compound Slide Nut) on page 30 of
the Clausing manual.

The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly) also
on page 30.


Some of these days I'll get a chunk of bronze of adequate size
and use it to make a new nut. Then I'll make a matching leadscrew so I
am ready for the next time it wears out. :-) And -- this will give me
practice in making spare leadscrews and nuts for the taper attachment
too, so if the taper attachment wears fast, I can swap back in a normal
nut and leadscrew. (Actually -- the leadscrew is identical for both
the standard cross slide and my taper attachment -- but not for the
fancier taper attachment with the telescoping leadscrew.

So that's the distinction between telescoping and non-telescoping taper
attachments. What are the advantages and disadvantages of the two
approaches?


The part I'm talking about above is a very thick washer (Tool Post
Washer, C-375) that fits over the toolpost, and having a shallow slot
milled into one face to accept the rocker (Tool Post Wedge, C-378). The
bottom of the slot appears to be spherical.

Interestingly, the drawing (page 30) in the Clausing 5914 manual shows a
washer with a full spherical seat on one side, versus a slot, so the
slotted washer was probably a later design. The slotted washer is
probably easier to make, and stronger.

Aha! It suddenly makes sense what you have been saying. i've
only ever seen the ones with the full spherical relief on the washer.

It may be easy to machine a convex sphere on the end of a 3" round bar
and then cut it off the bar, and slice parallel to a diameter twice to
yield a rocker.


But to my mind it would *have* to be a conical section at least
to handle the motion of the rocker.

Well, ellipses would not do either - it has to be spherical.


As for a tool to measure the radius -- try three rods on a set of
three collars which can allow the rods to both pivot and to slide back
and forth to set a radius. The extension of the rods which allows the
rods to pivot throughout the range of the curve and have all three
continue touching would be set to the true radius. I've seen such a
tool in an old Machinist's toolbox.

I'm not visualizing this.

It doesn't matter, though this would still work even with your
slotted washer instead of the turned washer.

I can't really do a full ASCII drawing, but pictu
_
| |
||||||||||||||| --- knurled nut
+-------+
| |
| 0 |1
| |
+-------+
+-------+
| |
| 0 |2
| |
+-------+
+-------+
| |
| 0 |3
| |
+-------+
||||||||||||||| --- knurled nut
|_|


a) Now -- part (2) there has a threaded shaft projecting from each
end through (1) and (3)

b) The holes, (shown as '0' in each part) are off center enough to
clear the threaded shafts passing through parts (1) and (3).

c) Not shown -- small thumbscrews to lock shafts into the holes.
Loosen them and the shafts slide, tighten them and the shafts
are locked in place.

d) The shaft in (2) is straight, coming to a point.

e) The shafts in (1) and (3) are straight except at the end where
they are bent in to almost touch the tip of the shaft in (2).

f) If you adjust the shafts so the tips are the same distance from
the centerline of the assembly above, then loosen the knurled
nuts and pivot each to they are forming something like "|",
all three points will touch on a curve of a radius which matches
the distance of the tips from the centerline. If the radius is
larger or smaller, only two of the tips will touch.

g) So -- the trick is how to measure the radius of the tip from the
center. For that, you will have to design and make your own
fixture. I've "designed" the tool. :-)

h) Note that the holes in (b) above *could* be on center if the
studs are large enough to accept a through hole with a
countersink bevel on each side -- though this would limit the
swiveling of the rods to something like +/- 45 degrees or so.

I see. It's the machinist's equivalent to the optician's three-prong
instrument to measure lens surface curvature. The only problem is that
there is no place for the center leg to land unless one makes the whole
assembly small enough to fit on one side of the washer, avoiding the
hole through which the toolpost projects. I'll have to think about this.


I think that the cylinder is intentional for sure - the cylinder is
cheaper to make. With a section of a sphere, clamping is firm and
distributed over a broad area even if the bar being clamped isn't quite
rectangular. Which is why Clausing went to all that trouble.

Have you seen a true Clausing one to be sure that this was the
case? I don't think that Clausing made the toolposts for their lathes
-- they just bought from Armstrong. The parts are all forged, and it
makes more sense to get them from a vendor who is already set up to make
forged tools than to make one yourself for the machine in question.

I have no way to know if what I have is true Clausing. What I have was
machined, not forged, and lacks Armstrong markings. Although the rocker
could have been forged. Or forged then machined. Not having the
rocker, it's hard to say.

It may be a shop-made replacement.

I think I was unclear. The slotted washer appears to have been made by
Clausing, and was machined from flat stock. I did not receive the
matching rocker, and purchased a replacement that does appear to be from
Armstrong that is in fact forged. This replacement rocker seems to have
the correct radius, but is a cylinder versus a sphere. The speculation
is that Clausing could purchase forged rockers and machine the sphere to
replace the cylinder. But Clausing seems more likely to machine the
rockers from flat stock.


But -- I wouldn't worry about it anyway. My Clausing came to me
without a lantern style toolpost, and I have been happy to keep it like
that. :-)

My reason is that lantern toolpost tooling does come up used around
here, and it's worthwhile to be able to use it, as it often goes begging.

Well ... I have lantern toolpost and holders for the 6x16"
Atlas/Craftsman -- but I also don't *use* that lathe any more. it was
in pretty bad shape when I first got it -- including some hacksaw
notches in the bed, and significant bed wear near the chucks. It also
had two chucks which were obviously made for the 10" or 12" Atlas, and a
threaded bushing to adapt the two of them to the spindle of the 6x18. :-)
This hastened wear on the spindle bearings (bushings, not roller as in
the later ones).

But it did help me for quite a while until I got better
machines. If I were to use it today, I would make a quick-change
toolpost (of some sort) for it -- or try one of the smaller ones sold to
the hobby crowd.

As it is -- the last significant metalwork related to it was
making something *for* it instead of *with* it. A parting tool hung up
and split off half of the T-slot in the compound top slide, so I had to
make a replacement of good tool steel, instead of the original cast
iron. More recently, I spent some time with the surface grinder turning
the milling spirals on the surface into a nicer finish.

Ouch. That Atlas was just a bit too light duty. What was being parted
off that caught the parting tool?


Joe Gwinn

On 2008-03-06, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-05, Joseph Gwinn wrote:

[ ... ]

Well, no turret in my batch. But I'm liking Aloris better and better.

You might find a turret on eBay -- I've seen them for sale from
time to time. But it won't be a matching serial number. :-) I believe
that I pointed you to a PDF scan of the manual (very faded
third-generation Xerox copy), and from that you can get several possible
part numbers -- all were interchangeable, apparently.

The implication being that one assembles a full turret from parts
acquired one by one on eBay?

No -- one gets a complete turret -- though one accumulates the
tools to load the turret from separate eBay purchases.

But -- there are several models of turret which could be used.
All fit the 12" swing and the width of bed which is common between my
5418 and your 5914.

Actually, a taper attachment is higher on my list. I did see a
telescoping taper attachment for a Clausing lathe other than 5900 series
listed on eBay yesterday, but gone today. Taper attachments are
model-specific, so I didn't pay much attention.

O.K. Though the ones for the 5400 series and for the 5900
series may be interchangeable -- depending on how the nut is
implemented.


The boring bar hole in various holders is probably pretty good, as
Aloris makes them on some kind if production line, but they make no
claim of repeatability between holders.

And if you mix manufacturers, the difference may be much
greater.

Yep.

And since some of my tooling is always purchased used, there may
have been changes in Aloris' dimensions over the years, too.

I bet that Aloris keeps them pretty accurate, so their industrial
customers don't yell at them.

But the distance from the dovetails to the center of the bore
on a boring bar holder is not a critical dimension for use as designed.
Yes, it would be if you were using it to imitate a turret. :-)

Given that the Aloris-type toolposts and toolholders are
interchangeable, and acknowledged as such in the Aloris catalog, I bet
that Aloris has shared the critical drawings with their competitors, the
probable intent being to make the pie bigger for all. I would guess
that this happened as the expiration of the key patents loomed.

Toolpost, original: 2,972,272

Toolpost, indexable: 6,230,595

Cut-off tool: 3,455,001

Holder for triangle inserts: 3,280,450

Too late to check those out tonight. I'm due in bed. Been
tearing apart a dead HP LaserJet 5 color so I can get it down the
stairs. That thing is *heavy* when fully assembled. I'll keep typing
until my watch completes its try to contact WWVB to verify its time
setting at 2:00 AM. :-)

[ ... ]

Most of the problem seems to be in the nut. Maybe I'll make a new nut.
It was pretty simply shaped, and an Acme tap set is probably cheaper
than a new nut from Clausing. It's $48.50.

First thing to be careful about. The thread is 1/2-10 Acme
*LH*, and all of the combination roughing/finishing Acme taps have been
right-hand only. I did get a left-hand Acme tap of the right thread,
but IIRC it cost nearly as much as the nut at that time.

Hmm. Cut on the lathe?

Cut the leadscrew on the lathe -- with a follower rest. I tried
one in aluminum as an experiment, but I made the mistake of cutting it
right-hand thread, so the test failed. But it looks as though I can do
a good job.

However, I think that trying to do internal threading with a
single-point tool for a 1/2" diameter leadscrew in bronze (nasty stuff
to thread with a flexing tool) might be beyond me. For that I *might*
rough it with a single-point and then use the tap to complete the job,
since I already have the LH tap. I forget what the minor diameter is
for a 1/2-10 Acme thread, but it is pretty small.


What does your nut look like? Mine looks like a plumbing Tee,
with the Acme thread through the two straight sides, and the upright of

[ ... ]

The nut I'm talking about is a cylinder with the threaded hole
crosswise. It is part number DL-471 (Compound Slide Nut) on page 30 of
the Clausing manual.

Hmm ... how does it attach? IIRC, my Clausing manual does not
cover that style. And it is too late to dig it out to be sure.

The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly) also
on page 30.

O.K. That one is what I am accustomed to.


Some of these days I'll get a chunk of bronze of adequate size
and use it to make a new nut. Then I'll make a matching leadscrew so I
am ready for the next time it wears out. :-) And -- this will give me
practice in making spare leadscrews and nuts for the taper attachment
too, so if the taper attachment wears fast, I can swap back in a normal
nut and leadscrew. (Actually -- the leadscrew is identical for both
the standard cross slide and my taper attachment -- but not for the
fancier taper attachment with the telescoping leadscrew.

So that's the distinction between telescoping and non-telescoping taper
attachments. What are the advantages and disadvantages of the two
approaches?

The non-telescoping one uses the standard leadscrew and threads
it into a nut which can be clamped either to the back of the cross
slide, or to the follower on the taper attachment.

The telescoping style has the crank connected to a spline which
fits into the leadscrew, and the far end of the leadscrew threads into
the the follower and is mounted in a bearing in the cross slide, IIRC.
(I should dig up the manuals on PDF to see which is which, but the watch
has completed its resetting. It and the computer now agree to the
second, instead of being off by a full second. :-)

[ ... ]

Aha! It suddenly makes sense what you have been saying. i've
only ever seen the ones with the full spherical relief on the washer.

It may be easy to machine a convex sphere on the end of a 3" round bar
and then cut it off the bar, and slice parallel to a diameter twice to
yield a rocker.

Agreed.

But to my mind it would *have* to be a conical section at least
to handle the motion of the rocker.

Well, ellipses would not do either - it has to be spherical.

Sorry -- I meant cylindrical, not conical. :-)

[ ... radius measuring tool description snipped ... ]

I see. It's the machinist's equivalent to the optician's three-prong
instrument to measure lens surface curvature. The only problem is that
there is no place for the center leg to land unless one makes the whole
assembly small enough to fit on one side of the washer, avoiding the
hole through which the toolpost projects. I'll have to think about this.

If you can swing two of the arms to near the OD and the ID of
one side, and the other arm to near the OD of the other side, you should
be fine. But finding a coin of the right diameter would probably be
easier to do. :-)

[ ... ]

I have no way to know if what I have is true Clausing. What I have was
machined, not forged, and lacks Armstrong markings. Although the rocker
could have been forged. Or forged then machined. Not having the
rocker, it's hard to say.

It may be a shop-made replacement.

I think I was unclear. The slotted washer appears to have been made by
Clausing,

Why does it appear to have been made by Clausing?

and was machined from flat stock. I did not receive the
matching rocker, and purchased a replacement that does appear to be from
Armstrong that is in fact forged. This replacement rocker seems to have
the correct radius, but is a cylinder versus a sphere. The speculation
is that Clausing could purchase forged rockers and machine the sphere to
replace the cylinder. But Clausing seems more likely to machine the
rockers from flat stock.

O.K. Perhaps. But the ring sounds more like shop-made unless
you see markings to indicate that it was made by Clausing. Just because
it came with the lathe does not mean that it has always been with the
lathe. :-)

[ ... 6x18" lathe ... ]

As it is -- the last significant metalwork related to it was
making something *for* it instead of *with* it. A parting tool hung up
and split off half of the T-slot in the compound top slide, so I had to
make a replacement of good tool steel, instead of the original cast
iron. More recently, I spent some time with the surface grinder turning
the milling spirals on the surface into a nicer finish.

Ouch. That Atlas was just a bit too light duty. What was being parted
off that caught the parting tool?

It was a length of square stock -- 4?? stainless steel as it
turns out, about 1-1/4" square which was too long to support the far end
by a tailstock center, and I had no steady rest even if I had the
ability to make a square to cylinder adaptor -- which I did not at that
time. And, I did not have a horizontal bandsaw at the time, either.
Nor did I have the patience to use a hacksaw on it.

I was cutting off about 1" from the 4-jaw chuck jaws. Really
asking too much of such a light duty lathe. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-03-06, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-05, Joseph Gwinn wrote:

[ ... ]

Well, no turret in my batch. But I'm liking Aloris better and better.

You might find a turret on eBay -- I've seen them for sale from
time to time. But it won't be a matching serial number. :-) I believe
that I pointed you to a PDF scan of the manual (very faded
third-generation Xerox copy), and from that you can get several possible
part numbers -- all were interchangeable, apparently.

The implication being that one assembles a full turret from parts
acquired one by one on eBay?

No -- one gets a complete turret -- though one accumulates the
tools to load the turret from separate eBay purchases.

But -- there are several models of turret which could be used.
All fit the 12" swing and the width of bed which is common between my
5418 and your 5914.

OK.


Actually, a taper attachment is higher on my list. I did see a
telescoping taper attachment for a Clausing lathe other than 5900 series
listed on eBay yesterday, but gone today. Taper attachments are
model-specific, so I didn't pay much attention.

O.K. Though the ones for the 5400 series and for the 5900
series may be interchangeable -- depending on how the nut is
implemented.

Details, details.


The boring bar hole in various holders is probably pretty good, as
Aloris makes them on some kind if production line, but they make no
claim of repeatability between holders.

And if you mix manufacturers, the difference may be much
greater.

Yep.

And since some of my tooling is always purchased used, there may
have been changes in Aloris' dimensions over the years, too.

I bet that Aloris keeps them pretty accurate, so their industrial
customers don't yell at them.

But the distance from the dovetails to the center of the bore
on a boring bar holder is not a critical dimension for use as designed.

Nonetheless, I bet it doesn't vary much.


Yes, it would be if you were using it to imitate a turret. :-)

That would be their "Indexable" line.


Given that the Aloris-type toolposts and toolholders are
interchangeable, and acknowledged as such in the Aloris catalog, I bet
that Aloris has shared the critical drawings with their competitors, the
probable intent being to make the pie bigger for all. I would guess
that this happened as the expiration of the key patents loomed.

Toolpost, original: 2,972,272

Toolpost, indexable: 6,230,595

Cut-off tool: 3,455,001

Holder for triangle inserts: 3,280,450

Too late to check those out tonight. I'm due in bed. Been
tearing apart a dead HP LaserJet 5 color so I can get it down the
stairs. That thing is *heavy* when fully assembled. I'll keep typing
until my watch completes its try to contact WWVB to verify its time
setting at 2:00 AM. :-)

Reading patents can substitute for counting sheep.


Most of the problem seems to be in the nut. Maybe I'll make a new nut.
It was pretty simply shaped, and an Acme tap set is probably cheaper
than a new nut from Clausing. It's $48.50.

First thing to be careful about. The thread is 1/2-10 Acme
*LH*, and all of the combination roughing/finishing Acme taps have been
right-hand only. I did get a left-hand Acme tap of the right thread,
but IIRC it cost nearly as much as the nut at that time.

Hmm. Cut on the lathe?

Cut the leadscrew on the lathe -- with a follower rest. I tried
one in aluminum as an experiment, but I made the mistake of cutting it
right-hand thread, so the test failed. But it looks as though I can do
a good job.

It ought to work, although I would have to fabricate a follower rest for
the job as well.


However, I think that trying to do internal threading with a
single-point tool for a 1/2" diameter leadscrew in bronze (nasty stuff
to thread with a flexing tool) might be beyond me.

Use a solid carbide internal threading boring bar?

Or, mount the nut on the slide and a bar between centers with HSS
toolbit in the center of the bar, perpendicular to the bar, the bar
passing through the nut. I've seen this setup used for line boring of
bearings on electric motors.


For that I *might*
rough it with a single-point and then use the tap to complete the job,
since I already have the LH tap. I forget what the minor diameter is
for a 1/2-10 Acme thread, but it is pretty small.

That could work.


What does your nut look like? Mine looks like a plumbing Tee,
with the Acme thread through the two straight sides, and the upright of

[ ... ]

The nut I'm talking about is a cylinder with the threaded hole
crosswise. It is part number DL-471 (Compound Slide Nut) on page 30 of
the Clausing manual.

Hmm ... how does it attach? IIRC, my Clausing manual does not
cover that style. And it is too late to dig it out to be sure.

The cylinder fits snugly into a hole in the Compound Slide (704-34), and
is held in place by a single setscrew.


The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly) also
on page 30.

O.K. That one is what I am accustomed to.


Some of these days I'll get a chunk of bronze of adequate size
and use it to make a new nut. Then I'll make a matching leadscrew so I
am ready for the next time it wears out. :-) And -- this will give me
practice in making spare leadscrews and nuts for the taper attachment
too, so if the taper attachment wears fast, I can swap back in a normal
nut and leadscrew. (Actually -- the leadscrew is identical for both
the standard cross slide and my taper attachment -- but not for the
fancier taper attachment with the telescoping leadscrew.

So that's the distinction between telescoping and non-telescoping taper
attachments. What are the advantages and disadvantages of the two
approaches?

The non-telescoping one uses the standard leadscrew and threads
it into a nut which can be clamped either to the back of the cross
slide, or to the follower on the taper attachment.

Ahh. And it's bad karma to engage both clamps at once.


The telescoping style has the crank connected to a spline which
fits into the leadscrew, and the far end of the leadscrew threads into
the the follower and is mounted in a bearing in the cross slide, IIRC.
(I should dig up the manuals on PDF to see which is which, but the watch
has completed its resetting. It and the computer now agree to the
second, instead of being off by a full second. :-)

OK. Comparative benefits?


[ ... radius measuring tool description snipped ... ]

I see. It's the machinist's equivalent to the optician's three-prong
instrument to measure lens surface curvature. The only problem is that
there is no place for the center leg to land unless one makes the whole
assembly small enough to fit on one side of the washer, avoiding the
hole through which the toolpost projects. I'll have to think about this.

If you can swing two of the arms to near the OD and the ID of
one side, and the other arm to near the OD of the other side, you should
be fine. But finding a coin of the right diameter would probably be
easier to do. :-)

There were large iron coins used in antiquity. Like our shops.


I have no way to know if what I have is true Clausing. What I have was
machined, not forged, and lacks Armstrong markings. Although the rocker
could have been forged. Or forged then machined. Not having the
rocker, it's hard to say.

It may be a shop-made replacement.

I think I was unclear. The slotted washer appears to have been made by
Clausing,

Why does it appear to have been made by Clausing?

Style and finish, basically. I cannot see a shopmade item going to all
that trouble, versus buying something from Armstrong.

By the way, I looked at the Armstrong website, and the rocker I bought
was not made by Armstrong, although it looks to be interchangeable with
Armstrong. What I have is marked with a flattened diamond and the
number "10". Any idea who makes or made this?


and was machined from flat stock. I did not receive the
matching rocker, and purchased a replacement that does appear to be from
Armstrong that is in fact forged. This replacement rocker seems to have
the correct radius, but is a cylinder versus a sphere. The speculation
is that Clausing could purchase forged rockers and machine the sphere to
replace the cylinder. But Clausing seems more likely to machine the
rockers from flat stock.

O.K. Perhaps. But the ring sounds more like shop-made unless
you see markings to indicate that it was made by Clausing. Just because
it came with the lathe does not mean that it has always been with the
lathe. :-)

Clausing does not seem to mark the pieces of their lathes, only the
lathe itself. As mentioned above, I doubt that the ring was shopmade.


[ ... 6x18" lathe ... ]

As it is -- the last significant metalwork related to it was
making something *for* it instead of *with* it. A parting tool hung up
and split off half of the T-slot in the compound top slide, so I had to
make a replacement of good tool steel, instead of the original cast
iron. More recently, I spent some time with the surface grinder turning
the milling spirals on the surface into a nicer finish.

Ouch. That Atlas was just a bit too light duty. What was being parted
off that caught the parting tool?

It was a length of square stock -- 4?? stainless steel as it
turns out, about 1-1/4" square which was too long to support the far end
by a tailstock center, and I had no steady rest even if I had the
ability to make a square to cylinder adaptor -- which I did not at that
time. And, I did not have a horizontal bandsaw at the time, either.
Nor did I have the patience to use a hacksaw on it.

I was cutting off about 1" from the 4-jaw chuck jaws. Really
asking too much of such a light duty lathe. :-)

I'll say. Interrupted cut and all.

Joe Gwinn

On 2008-03-07, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

Actually, a taper attachment is higher on my list. I did see a
telescoping taper attachment for a Clausing lathe other than 5900 series
listed on eBay yesterday, but gone today. Taper attachments are
model-specific, so I didn't pay much attention.

O.K. Though the ones for the 5400 series and for the 5900
series may be interchangeable -- depending on how the nut is
implemented.

Details, details.

Well ... you are talking of your nut being a cylinder, while
mine is a "Tee" so there could be interchangablity problems. This might
require the telescoping taper attachment to fit.

[ ... ]

I bet that Aloris keeps them pretty accurate, so their industrial
customers don't yell at them.

But the distance from the dovetails to the center of the bore
on a boring bar holder is not a critical dimension for use as designed.

Nonetheless, I bet it doesn't vary much.

Probably not -- but is it accurate enough for substituting for a
turret? (And you would need an easy way to lock the cross-slide so it
did not vibrate off center.

[ ... ]

Too late to check those out tonight. I'm due in bed. Been
tearing apart a dead HP LaserJet 5 color so I can get it down the
stairs. That thing is *heavy* when fully assembled. I'll keep typing
until my watch completes its try to contact WWVB to verify its time
setting at 2:00 AM. :-)

Reading patents can substitute for counting sheep.

Not according to my wife. :-)

Most of the problem seems to be in the nut. Maybe I'll make a new nut.
It was pretty simply shaped, and an Acme tap set is probably cheaper
than a new nut from Clausing. It's $48.50.

First thing to be careful about. The thread is 1/2-10 Acme
*LH*, and all of the combination roughing/finishing Acme taps have been
right-hand only. I did get a left-hand Acme tap of the right thread,
but IIRC it cost nearly as much as the nut at that time.

Hmm. Cut on the lathe?

Cut the leadscrew on the lathe -- with a follower rest. I tried
one in aluminum as an experiment, but I made the mistake of cutting it
right-hand thread, so the test failed. But it looks as though I can do
a good job.

It ought to work, although I would have to fabricate a follower rest for
the job as well.

O.K.


However, I think that trying to do internal threading with a
single-point tool for a 1/2" diameter leadscrew in bronze (nasty stuff
to thread with a flexing tool) might be beyond me.

Use a solid carbide internal threading boring bar?

Compare the price of a solid carbide internal threading tool
ground for left-hand thread 10 TPI Acme to a left-hand Acme tap at 10
TPI. :-)

Or, mount the nut on the slide and a bar between centers with HSS
toolbit in the center of the bar, perpendicular to the bar, the bar
passing through the nut. I've seen this setup used for line boring of
bearings on electric motors.

Again -- the bar is likely to be pretty skinny. The minor
diameter for a 1/2" 10 TPI Acme (LH or RH won't make much difference)
for class 2G threads is:

Max: 0.3800"
Min: 0.3594"

so -- with a 3/8" rod, and max diameter you would have 0.0025" clearance
for the chips -- and all other options are less. Anything smaller than
3/8" diameter would be even worse in terms of rigidity (and even windup
of the rod). I don't think that I would want to single-point that
thread.

[ ... ]

What does your nut look like? Mine looks like a plumbing Tee,
with the Acme thread through the two straight sides, and the upright of

[ ... ]

The nut I'm talking about is a cylinder with the threaded hole
crosswise. It is part number DL-471 (Compound Slide Nut) on page 30 of
the Clausing manual.

Hmm ... how does it attach? IIRC, my Clausing manual does not
cover that style. And it is too late to dig it out to be sure.

The cylinder fits snugly into a hole in the Compound Slide (704-34), and
is held in place by a single setscrew.

O.K. So the hole is a lot shorter than it is in the "Tee"
design and the cylinder is mounted with its axis vertical? That would
interchange with the original Tee -- but would wear a lot faster with
fewer threads engaged.

The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly) also
on page 30.

No page 30 in my manual. Mine stops at page 20 -- exclusive of
the un-numbered lubrication chart.

[ ... ]

So that's the distinction between telescoping and non-telescoping taper
attachments. What are the advantages and disadvantages of the two
approaches?

The non-telescoping one uses the standard leadscrew and threads
it into a nut which can be clamped either to the back of the cross
slide, or to the follower on the taper attachment.

Ahh. And it's bad karma to engage both clamps at once.

Yes -- though not too bad as long as you don't have the slide
clamped to the bed -- or if the taper bar is set to zero taper.


The telescoping style has the crank connected to a spline which
fits into the leadscrew, and the far end of the leadscrew threads into
the the follower and is mounted in a bearing in the cross slide, IIRC.
(I should dig up the manuals on PDF to see which is which, but the watch
has completed its resetting. It and the computer now agree to the
second, instead of being off by a full second. :-)

OK. Comparative benefits?

Telescoping: Cost is much higher for the telescoping version.

Telescoping: The backlash in the spline adds to the total backlash in the
handwheel.

Telescoping: No juggling of two clamps to determine whether you are
in taper or non-taper mode.

Non-Tele: Cost is lower.

Non-Tele: less backlash.

Non-Tele: A bit more rigid in non-taper mode, because you don't
have the path going out to the follower and back as you
do in the Telescoping. And in the Tele, is *always* in
taper mode -- other than locking the slide to the bed.

I would probably prefer the telescoping if I were switching back
and forth a lot between taper and non, but for occasional use I prefer
the non-telescoping (which happens to be what I already have,
simplifying matters.

[ ... ]

I have no way to know if what I have is true Clausing. What I have was
machined, not forged, and lacks Armstrong markings. Although the rocker
could have been forged. Or forged then machined. Not having the
rocker, it's hard to say.

It may be a shop-made replacement.

I think I was unclear. The slotted washer appears to have been made by
Clausing,

Why does it appear to have been made by Clausing?

Style and finish, basically. I cannot see a shopmade item going to all
that trouble, versus buying something from Armstrong.

O.K. But the only drawing of the lantern style toolpost is the
page offering "Carriage Saddle and Compound Assembly" (Page 19) in my
manual. And the drawing of the ring looks like it is fully dished -- no
hint of a single groove like yours. The ring is C-375, and the whole
lantern style toolpost, less wrench, is C-377-S. The rocker, FWIW, is
C-378.

Could you do a good set of close-up photos of the ring and drop
them in the dropbox (http://www.metalworking.com). Direct e-mail to me
won't work -- there is a size limit on incoming e-mail which would
bounce it.

By the way, I looked at the Armstrong website, and the rocker I bought
was not made by Armstrong, although it looks to be interchangeable with
Armstrong. What I have is marked with a flattened diamond and the
number "10". Any idea who makes or made this?

No clue -- unless that is an older Armstrong. The number of
toolpost parts which they currently make is a lot fewer than they used
to make. Everybody is going Aloris style or equivalent.

[ ... ]

O.K. Perhaps. But the ring sounds more like shop-made unless
you see markings to indicate that it was made by Clausing. Just because
it came with the lathe does not mean that it has always been with the
lathe. :-)

Clausing does not seem to mark the pieces of their lathes, only the
lathe itself. As mentioned above, I doubt that the ring was shopmade.

O.K. But the slotted version is not shown in the manual
drawings for the 5418 at least. Can you find drawings showing the
slotted version in your manual?

[ ... ]

Ouch. That Atlas was just a bit too light duty. What was being parted
off that caught the parting tool?

It was a length of square stock -- 4?? stainless steel as it
turns out, about 1-1/4" square which was too long to support the far end
by a tailstock center, and I had no steady rest even if I had the
ability to make a square to cylinder adaptor -- which I did not at that
time. And, I did not have a horizontal bandsaw at the time, either.
Nor did I have the patience to use a hacksaw on it.

I was cutting off about 1" from the 4-jaw chuck jaws. Really
asking too much of such a light duty lathe. :-)

I'll say. Interrupted cut and all.

Actually, I was into the continuous cut point before it failed.

With the new compound top, some other part would fail first, I
think. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-03-07, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

Actually, a taper attachment is higher on my list. I did see a
telescoping taper attachment for a Clausing lathe other than 5900 series
listed on eBay yesterday, but gone today. Taper attachments are
model-specific, so I didn't pay much attention.

O.K. Though the ones for the 5400 series and for the 5900
series may be interchangeable -- depending on how the nut is
implemented.

Details, details.

Well ... you are talking of your nut being a cylinder, while
mine is a "Tee" so there could be interchangablity problems. This might
require the telescoping taper attachment to fit.

[ ... ]

I bet that Aloris keeps them pretty accurate, so their industrial
customers don't yell at them.

But the distance from the dovetails to the center of the bore
on a boring bar holder is not a critical dimension for use as designed.

Nonetheless, I bet it doesn't vary much.

Probably not -- but is it accurate enough for substituting for a
turret? (And you would need an easy way to lock the cross-slide so it
did not vibrate off center.

Yeah, but Aloris cannot fix that.


Too late to check those out tonight. I'm due in bed. Been
tearing apart a dead HP LaserJet 5 color so I can get it down the
stairs. That thing is *heavy* when fully assembled. I'll keep typing
until my watch completes its try to contact WWVB to verify its time
setting at 2:00 AM. :-)

Reading patents can substitute for counting sheep.

Not according to my wife. :-)

She reads patents on tooling, with interest? This is quite the wife.


However, I think that trying to do internal threading with a
single-point tool for a 1/2" diameter leadscrew in bronze (nasty stuff
to thread with a flexing tool) might be beyond me.

Use a solid carbide internal threading boring bar?

Compare the price of a solid carbide internal threading tool
ground for left-hand thread 10 TPI Acme to a left-hand Acme tap at 10
TPI. :-)

But the carbide tool has more uses.


Or, mount the nut on the slide and a bar between centers with HSS
toolbit in the center of the bar, perpendicular to the bar, the bar
passing through the nut. I've seen this setup used for line boring of
bearings on electric motors.

Again -- the bar is likely to be pretty skinny. The minor
diameter for a 1/2" 10 TPI Acme (LH or RH won't make much difference)
for class 2G threads is:

Max: 0.3800"
Min: 0.3594"

so -- with a 3/8" rod, and max diameter you would have 0.0025" clearance
for the chips -- and all other options are less. Anything smaller than
3/8" diameter would be even worse in terms of rigidity (and even windup
of the rod). I don't think that I would want to single-point that
thread.

It would be slow for sure, but the point of holding both ends with
cutter in the center is a substantial increase in rigidity compared to a
bar held from one end only.

The following max-deflection formulas are from Roark, Formulas for
Stress and Strain, 4th edition, 1965, Table III, formulas 1, 11, 21, and
31.

Cantilever, end load (formula 1): 0.3333 l^3 W/(EI)

Center load, both ends supported but able to rotate (11): 0.02083 L^3
W/(EI)

Center load, both ends supported but only one end is able to rotate
(21): 0.00932 L^3 W/(EI)

Center load, both ends supported and neither is able to rotate (31):
0.005208 L^3 W/(EI)


The "W/(EI)" is constant in the present case. (For the record, W is the
sideways force applied to the beam, E is the modulus of elasticity of
the beam material, and I is the moment of inertia of the beam's cross
section shape.)

Between formula 1 and the other formulas, the length of the beam
differs, as the cantilever with toolbit at one end is half the length of
the beam supported at both ends with toolbit in the center. So, in the
formulas above, the "l" in "l^3" is one half the length of the "L" in
"L^3".

So, let's put it all together, and drop the "W/(EI)" part as it is the
same for all cases considered here; and because L=2*l, set L^3=8 and
l^3=1:

Cantilever, end load (formula 1): 0.3333 l^3 - 0.3333 (1 times
stiffer)

Center load, both ends supported but able to twist (11): 0.02083 L^3 -
0.1667 (0.3333/0.1667= 2 times stiffer)

Center load, both ends supported but only one end is able to twist (21):
0.00932 L^3 - 0.07696 (0.3333/0.00932= 4.3 times stiffer)

Center load, both ends supported and neither end is able to twist (31):
0.005208 L^3 - 0.04166 (8 times stiffer)

The conclusion is that if the bar is held in a collet at the headstock
and a live center at the tailstock, with toolbit in the center, one
achieves four times the stiffness than if the part of the bar from the
toolbit to the tailstock is removed.

If the tailstock end of the bar is instead held in a rotating chuck, we
get eight times the stiffness.



What does your nut look like? Mine looks like a plumbing Tee,
with the Acme thread through the two straight sides, and the upright of

[ ... ]

The nut I'm talking about is a cylinder with the threaded hole
crosswise. It is part number DL-471 (Compound Slide Nut) on page 30 of
the Clausing manual.

Hmm ... how does it attach? IIRC, my Clausing manual does not
cover that style. And it is too late to dig it out to be sure.

The cylinder fits snugly into a hole in the Compound Slide (704-34), and
is held in place by a single setscrew.

O.K. So the hole is a lot shorter than it is in the "Tee"
design and the cylinder is mounted with its axis vertical? That would
interchange with the original Tee -- but would wear a lot faster with
fewer threads engaged.

So it appears - this axis is by far the loosest.

I should measure wear on the screw - perhaps all I need is to replace
the nut.


The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly) also
on page 30.

No page 30 in my manual. Mine stops at page 20 -- exclusive of
the un-numbered lubrication chart.

Try page 19 in the 5418 manual. Both nuts are shown. The cylinder nut
is DL-471 and the T-shaped bronze nut is 990-069. The nuts on the 5914
look exactly the same.

On the 5914, the slide is flat-topped, not humped.


So that's the distinction between telescoping and non-telescoping taper
attachments. What are the advantages and disadvantages of the two
approaches?

The non-telescoping one uses the standard leadscrew and threads
it into a nut which can be clamped either to the back of the cross
slide, or to the follower on the taper attachment.

Ahh. And it's bad karma to engage both clamps at once.

Yes -- though not too bad as long as you don't have the slide
clamped to the bed -- or if the taper bar is set to zero taper.


The telescoping style has the crank connected to a spline which
fits into the leadscrew, and the far end of the leadscrew threads into
the the follower and is mounted in a bearing in the cross slide, IIRC.
(I should dig up the manuals on PDF to see which is which, but the watch
has completed its resetting. It and the computer now agree to the
second, instead of being off by a full second. :-)

OK. Comparative benefits?

Telescoping: Cost is much higher for the telescoping version.

Telescoping: The backlash in the spline adds to the total backlash in the
handwheel.

Telescoping: No juggling of two clamps to determine whether you are
in taper or non-taper mode.

Non-Tele: Cost is lower.

Non-Tele: less backlash.

Non-Tele: A bit more rigid in non-taper mode, because you don't
have the path going out to the follower and back as you
do in the Telescoping. And in the Tele, is *always* in
taper mode -- other than locking the slide to the bed.

I would probably prefer the telescoping if I were switching back
and forth a lot between taper and non, but for occasional use I prefer
the non-telescoping (which happens to be what I already have,
simplifying matters.

Sounds like non-telescoping would be best for me as well.


I have no way to know if what I have is true Clausing. What I have
was
machined, not forged, and lacks Armstrong markings. Although the
rocker
could have been forged. Or forged then machined. Not having the
rocker, it's hard to say.

It may be a shop-made replacement.

I think I was unclear. The slotted washer appears to have been made by
Clausing,

Why does it appear to have been made by Clausing?

Style and finish, basically. I cannot see a shopmade item going to all
that trouble, versus buying something from Armstrong.

O.K. But the only drawing of the lantern style toolpost is the
page offering "Carriage Saddle and Compound Assembly" (Page 19) in my
manual. And the drawing of the ring looks like it is fully dished -- no
hint of a single groove like yours. The ring is C-375, and the whole
lantern style toolpost, less wrench, is C-377-S. The rocker, FWIW, is
C-378.

The lantern toolpost is the same, right down to the part numbers, in the
5914 manual. I imagine that all 12" Clausing lathes got the same
lantern toolpost.


Could you do a good set of close-up photos of the ring and drop
them in the dropbox (http://www.metalworking.com). Direct e-mail to me
won't work -- there is a size limit on incoming e-mail which would
bounce it.

Will do, although it will be hard to see that the bottom of the slot is
spherical versus cylindrical.


By the way, I looked at the Armstrong website, and the rocker I bought
was not made by Armstrong, although it looks to be interchangeable with
Armstrong. What I have is marked with a flattened diamond and the
number "10". Any idea who makes or made this?

No clue -- unless that is an older Armstrong. The number of
toolpost parts which they currently make is a lot fewer than they used
to make. Everybody is going Aloris style or equivalent.

One assumes that the name somehow involved or implied the word "diamond".


O.K. Perhaps. But the ring sounds more like shop-made unless
you see markings to indicate that it was made by Clausing. Just because
it came with the lathe does not mean that it has always been with the
lathe. :-)

Clausing does not seem to mark the pieces of their lathes, only the
lathe itself. As mentioned above, I doubt that the ring was shopmade.

O.K. But the slotted version is not shown in the manual
drawings for the 5418 at least. Can you find drawings showing the
slotted version in your manual?

All drawings I have show the dished washer as well. My suspicion is
that the slotted washer is a later twist, perhaps late production, or
perhaps from a later model retrofitted to the 5914.

Or even from some other brand of lathe entirely. All I really know is
that the post itself looks like what's in the Clausing manual, and that
the washer was not made by Armstrong.

Maybe the cheap fix is to buy an Armstrong washer and rocker to fit the
existing lantern post. J&L carries Armstrong toolposts et al.


Ouch. That Atlas was just a bit too light duty. What was being parted
off that caught the parting tool?

It was a length of square stock -- 4?? stainless steel as it
turns out, about 1-1/4" square which was too long to support the far end
by a tailstock center, and I had no steady rest even if I had the
ability to make a square to cylinder adaptor -- which I did not at that
time. And, I did not have a horizontal bandsaw at the time, either.
Nor did I have the patience to use a hacksaw on it.

I was cutting off about 1" from the 4-jaw chuck jaws. Really
asking too much of such a light duty lathe. :-)

I'll say. Interrupted cut and all.

Actually, I was into the continuous cut point before it failed.

With the new compound top, some other part would fail first, I
think. :-)

I wouldn't make it _too_ strong, as subsequent parts are ever larger and
more expensive to replace.


Joe Gwinn

On 2008-03-08, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-07, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

O.K. Though the ones for the 5400 series and for the 5900
series may be interchangeable -- depending on how the nut is
implemented.

Details, details.

Well ... you are talking of your nut being a cylinder, while
mine is a "Tee" so there could be interchangablity problems. This might
require the telescoping taper attachment to fit.

[ ... ]

Too late to check those out tonight. I'm due in bed. Been
tearing apart a dead HP LaserJet 5 color so I can get it down the
stairs. That thing is *heavy* when fully assembled. I'll keep typing
until my watch completes its try to contact WWVB to verify its time
setting at 2:00 AM. :-)

Reading patents can substitute for counting sheep.

Not according to my wife. :-)

She reads patents on tooling, with interest? This is quite the wife.

No -- she questions some of my bedtime reading material,
including almost any technical material. :-)


However, I think that trying to do internal threading with a
single-point tool for a 1/2" diameter leadscrew in bronze (nasty stuff
to thread with a flexing tool) might be beyond me.

Use a solid carbide internal threading boring bar?

Compare the price of a solid carbide internal threading tool
ground for left-hand thread 10 TPI Acme to a left-hand Acme tap at 10
TPI. :-)

But the carbide tool has more uses.

Not if if is ground to cut Acme thread profiles at the 10 TPI
size. There is not much else that it can do.


Or, mount the nut on the slide and a bar between centers with HSS
toolbit in the center of the bar, perpendicular to the bar, the bar
passing through the nut. I've seen this setup used for line boring of
bearings on electric motors.

Again -- the bar is likely to be pretty skinny. The minor
diameter for a 1/2" 10 TPI Acme (LH or RH won't make much difference)
for class 2G threads is:

Max: 0.3800"
Min: 0.3594"

so -- with a 3/8" rod, and max diameter you would have 0.0025" clearance
for the chips -- and all other options are less. Anything smaller than
3/8" diameter would be even worse in terms of rigidity (and even windup
of the rod). I don't think that I would want to single-point that
thread.

It would be slow for sure, but the point of holding both ends with
cutter in the center is a substantial increase in rigidity compared to a
bar held from one end only.

And I left out of the calculations the fact that it would have
to be small enough to allow both the bar *and* the projection of the
tool to cut the full thread to slide into the bore before cutting
threads. And if it is *just* right in size, it makes how far you back
out of the thread prior to cranking back for the next pass more
sensitive.

The following max-deflection formulas are from Roark, Formulas for
Stress and Strain, 4th edition, 1965, Table III, formulas 1, 11, 21, and
31.

Cantilever, end load (formula 1): 0.3333 l^3 W/(EI)

Center load, both ends supported but able to rotate (11): 0.02083 L^3
W/(EI)

Center load, both ends supported but only one end is able to rotate
(21): 0.00932 L^3 W/(EI)

Center load, both ends supported and neither is able to rotate (31):
0.005208 L^3 W/(EI)


The "W/(EI)" is constant in the present case. (For the record, W is the
sideways force applied to the beam, E is the modulus of elasticity of
the beam material, and I is the moment of inertia of the beam's cross
section shape.)

Between formula 1 and the other formulas, the length of the beam
differs, as the cantilever with toolbit at one end is half the length of
the beam supported at both ends with toolbit in the center. So, in the
formulas above, the "l" in "l^3" is one half the length of the "L" in
"L^3".

So, let's put it all together, and drop the "W/(EI)" part as it is the
same for all cases considered here; and because L=2*l, set L^3=8 and
l^3=1:

Cantilever, end load (formula 1): 0.3333 l^3 - 0.3333 (1 times
stiffer)

Center load, both ends supported but able to twist (11): 0.02083 L^3 -
0.1667 (0.3333/0.1667= 2 times stiffer)

Center load, both ends supported but only one end is able to twist (21):
0.00932 L^3 - 0.07696 (0.3333/0.00932= 4.3 times stiffer)

Center load, both ends supported and neither end is able to twist (31):
0.005208 L^3 - 0.04166 (8 times stiffer)

The conclusion is that if the bar is held in a collet at the headstock
and a live center at the tailstock, with toolbit in the center, one
achieves four times the stiffness than if the part of the bar from the
toolbit to the tailstock is removed.

If the tailstock end of the bar is instead held in a rotating chuck, we
get eight times the stiffness.

Yes -- but how do you adjust the tool protrusion for the
subsequent passes? That is the tricky part, especially with a bar small
enough to clear both the cutting tool and the bar diameter through the
bore. You *do* have to advance the tool out of the bar, you can't do it
with the cross-slide leadscrew.

What does your nut look like? Mine looks like a plumbing Tee,
with the Acme thread through the two straight sides, and the upright of

[ ... ]

The nut I'm talking about is a cylinder with the threaded hole
crosswise. It is part number DL-471 (Compound Slide Nut) on page 30 of
the Clausing manual.

Hmm ... how does it attach? IIRC, my Clausing manual does not
cover that style. And it is too late to dig it out to be sure.

The cylinder fits snugly into a hole in the Compound Slide (704-34), and
is held in place by a single setscrew.

O.K. So the hole is a lot shorter than it is in the "Tee"
design and the cylinder is mounted with its axis vertical? That would
interchange with the original Tee -- but would wear a lot faster with
fewer threads engaged.

So it appears - this axis is by far the loosest.

I should measure wear on the screw - perhaps all I need is to replace
the nut.


The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly) also
on page 30.

No page 30 in my manual. Mine stops at page 20 -- exclusive of
the un-numbered lubrication chart.

Try page 19 in the 5418 manual. Both nuts are shown. The cylinder nut
is DL-471 and the T-shaped bronze nut is 990-069. The nuts on the 5914
look exactly the same.

Oh -- you are talking about the nut for the *compound*, not the
cross-slide. That looks even smaller in the drawings -- perhaps 3/8"
instead of 1/2". I thought that we were talking about the cross-slide
on the carriage, not the compound top slide.

How did we get that far apart?

On the 5914, the slide is flat-topped, not humped.

You mean the compound, not the cross-slide? I wonder why?

[ ... ]

OK. Comparative benefits?

[ ... ]

I would probably prefer the telescoping if I were switching back
and forth a lot between taper and non, but for occasional use I prefer
the non-telescoping (which happens to be what I already have,
simplifying matters.

Sounds like non-telescoping would be best for me as well.

And -- it should cost less, too. :-)

[ ... ]

It may be a shop-made replacement.

I think I was unclear. The slotted washer appears to have been made by
Clausing,

Why does it appear to have been made by Clausing?

Style and finish, basically. I cannot see a shopmade item going to all
that trouble, versus buying something from Armstrong.

O.K. But the only drawing of the lantern style toolpost is the
page offering "Carriage Saddle and Compound Assembly" (Page 19) in my
manual. And the drawing of the ring looks like it is fully dished -- no
hint of a single groove like yours. The ring is C-375, and the whole
lantern style toolpost, less wrench, is C-377-S. The rocker, FWIW, is
C-378.

The lantern toolpost is the same, right down to the part numbers, in the
5914 manual. I imagine that all 12" Clausing lathes got the same
lantern toolpost.

In which chase the ring shown is not the slotted ring which you
have.

Could you do a good set of close-up photos of the ring and drop
them in the dropbox (http://www.metalworking.com). Direct e-mail to me
won't work -- there is a size limit on incoming e-mail which would
bounce it.

Will do, although it will be hard to see that the bottom of the slot is
spherical versus cylindrical.

That was not what I was trying to determine. I just wanted to
see what it looked like so I could tell whether it felt Clausing-made to
me.

By the way, I looked at the Armstrong website, and the rocker I bought
was not made by Armstrong, although it looks to be interchangeable with
Armstrong. What I have is marked with a flattened diamond and the
number "10". Any idea who makes or made this?

No clue -- unless that is an older Armstrong. The number of
toolpost parts which they currently make is a lot fewer than they used
to make. Everybody is going Aloris style or equivalent.

One assumes that the name somehow involved or implied the word "diamond".

I don't find anything useful with a Google search using the
words Diamond and toolpost. Actually, I find mostly woodworking tools
in the first hits. :-)

[ ... ]

O.K. But the slotted version is not shown in the manual
drawings for the 5418 at least. Can you find drawings showing the
slotted version in your manual?

All drawings I have show the dished washer as well. My suspicion is
that the slotted washer is a later twist, perhaps late production, or
perhaps from a later model retrofitted to the 5914.

Or even from some other brand of lathe entirely. All I really know is
that the post itself looks like what's in the Clausing manual, and that
the washer was not made by Armstrong.

O.K. But the post is a very common design -- or at least was
back then.

Maybe the cheap fix is to buy an Armstrong washer and rocker to fit the
existing lantern post. J&L carries Armstrong toolposts et al.

Or -- to turn a ring to match the rocker which you have?

[ ... ]

I was cutting off about 1" from the 4-jaw chuck jaws. Really
asking too much of such a light duty lathe. :-)

I'll say. Interrupted cut and all.

Actually, I was into the continuous cut point before it failed.

With the new compound top, some other part would fail first, I
think. :-)

I wouldn't make it _too_ strong, as subsequent parts are ever larger and
more expensive to replace.

Well ... it is stronger mostly thanks to the materials which I
was able to find -- a good tough tool steel instead of cheap cast iron.
I wasn't setting out to make it stronger -- that is just what happened. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-03-08, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-07, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

O.K. Though the ones for the 5400 series and for the 5900
series may be interchangeable -- depending on how the nut is
implemented.

Details, details.

Well ... you are talking of your nut being a cylinder, while
mine is a "Tee" so there could be interchangablity problems. This might
require the telescoping taper attachment to fit.

[ ... ]

Too late to check those out tonight. I'm due in bed. Been
tearing apart a dead HP LaserJet 5 color so I can get it down the
stairs. That thing is *heavy* when fully assembled. I'll keep typing
until my watch completes its try to contact WWVB to verify its time
setting at 2:00 AM. :-)

Reading patents can substitute for counting sheep.

Not according to my wife. :-)

She reads patents on tooling, with interest? This is quite the wife.

No -- she questions some of my bedtime reading material,
including almost any technical material. :-)

I suspect that my wife would agree.


However, I think that trying to do internal threading with a
single-point tool for a 1/2" diameter leadscrew in bronze (nasty stuff
to thread with a flexing tool) might be beyond me.

Use a solid carbide internal threading boring bar?

Compare the price of a solid carbide internal threading tool
ground for left-hand thread 10 TPI Acme to a left-hand Acme tap at 10
TPI. :-)

But the carbide tool has more uses.

Not if if is ground to cut Acme thread profiles at the 10 TPI
size. There is not much else that it can do.

Right.


Or, mount the nut on the slide and a bar between centers with HSS
toolbit in the center of the bar, perpendicular to the bar, the bar
passing through the nut. I've seen this setup used for line boring of
bearings on electric motors.

Again -- the bar is likely to be pretty skinny. The minor
diameter for a 1/2" 10 TPI Acme (LH or RH won't make much difference)
for class 2G threads is:

Max: 0.3800"
Min: 0.3594"

so -- with a 3/8" rod, and max diameter you would have 0.0025" clearance
for the chips -- and all other options are less. Anything smaller than
3/8" diameter would be even worse in terms of rigidity (and even windup
of the rod). I don't think that I would want to single-point that
thread.

It would be slow for sure, but the point of holding both ends with
cutter in the center is a substantial increase in rigidity compared to a
bar held from one end only.

And I left out of the calculations the fact that it would have
to be small enough to allow both the bar *and* the projection of the
tool to cut the full thread to slide into the bore before cutting
threads. And if it is *just* right in size, it makes how far you back
out of the thread prior to cranking back for the next pass more
sensitive.

I visualize it as having a small bit held in a cross hole, held by a
perpendicular setscrew. One may need to use a 1.8" bit, such as used
for jewelry lathes.


The following max-deflection formulas are from Roark, Formulas for
Stress and Strain, 4th edition, 1965, Table III, formulas 1, 11, 21, and
31.

[snip]

The conclusion is that if the bar is held in a collet at the headstock
and a live center at the tailstock, with toolbit in the center, one
achieves four times the stiffness than if the part of the bar from the
toolbit to the tailstock is removed.

If the tailstock end of the bar is instead held in a rotating chuck, we
get eight times the stiffness.

Yes -- but how do you adjust the tool protrusion for the
subsequent passes? That is the tricky part, especially with a bar small
enough to clear both the cutting tool and the bar diameter through the
bore. You *do* have to advance the tool out of the bar, you can't do it
with the cross-slide leadscrew.

Correct. The cross-slide does not move during this operation.

By loosening the setscrew and moving the bit, using a depth mike to set
the protrusion as one creeps up on the correct cut depth.


What does your nut look like? Mine looks like a plumbing Tee,
with the Acme thread through the two straight sides, and the upright
of

[ ... ]

The nut I'm talking about is a cylinder with the threaded hole
crosswise. It is part number DL-471 (Compound Slide Nut) on page 30
of
the Clausing manual.

Hmm ... how does it attach? IIRC, my Clausing manual does not
cover that style. And it is too late to dig it out to be sure.

The cylinder fits snugly into a hole in the Compound Slide (704-34), and
is held in place by a single setscrew.

O.K. So the hole is a lot shorter than it is in the "Tee"
design and the cylinder is mounted with its axis vertical? That would
interchange with the original Tee -- but would wear a lot faster with
fewer threads engaged.

So it appears - this axis is by far the loosest.

I should measure wear on the screw - perhaps all I need is to replace
the nut.


The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly)
also
on page 30.

No page 30 in my manual. Mine stops at page 20 -- exclusive of
the un-numbered lubrication chart.

Try page 19 in the 5418 manual. Both nuts are shown. The cylinder nut
is DL-471 and the T-shaped bronze nut is 990-069. The nuts on the 5914
look exactly the same.

Oh -- you are talking about the nut for the *compound*, not the
cross-slide. That looks even smaller in the drawings -- perhaps 3/8"
instead of 1/2". I thought that we were talking about the cross-slide
on the carriage, not the compound top slide.

How did we get that far apart?

I've been trying to follow the nomenclature in the Clausing manual, for
better or for worse, even when it seems counter-intuitive. But I
suspect that nomenclature isn't uniform between manufacturers, which is
why I started to give the actual part number as well.


On the 5914, the slide is flat-topped, not humped.

You mean the compound, not the cross-slide? I wonder why?

In the 5914 manual (page 30), that T-slotted part is flat-topped and is
called the "Tool Post Slide" (704-033), and is dovetailed to the
"Compound Slide" (704-034), which in turn rotates upon the "Cross Slide"
(704-032).

In the 5418 manual (page 19), that same part is humpbacked and is called
simply the "Slide" (C-330), and is dovetailed to the "Lower Compound"
(DL-460), which rotates upon the "Cross Slide" (DL-458).

So, even within Clausing, the nomenclature varies. Thus the confusion.


OK. Comparative benefits?

[ ... ]

I would probably prefer the telescoping if I were switching back
and forth a lot between taper and non, but for occasional use I prefer
the non-telescoping (which happens to be what I already have,
simplifying matters.

Sounds like non-telescoping would be best for me as well.

And -- it should cost less, too. :-)

Yep. And now to find one.


It may be a shop-made replacement.

I think I was unclear. The slotted washer appears to have been made
by
Clausing,

Why does it appear to have been made by Clausing?

Style and finish, basically. I cannot see a shopmade item going to all
that trouble, versus buying something from Armstrong.

O.K. But the only drawing of the lantern style toolpost is the
page offering "Carriage Saddle and Compound Assembly" (Page 19) in my
manual. And the drawing of the ring looks like it is fully dished -- no
hint of a single groove like yours. The ring is C-375, and the whole
lantern style toolpost, less wrench, is C-377-S. The rocker, FWIW, is
C-378.

The lantern toolpost is the same, right down to the part numbers, in the
5914 manual. I imagine that all 12" Clausing lathes got the same
lantern toolpost.

In which chase the ring shown is not the slotted ring which you
have.

Correct.


Could you do a good set of close-up photos of the ring and drop
them in the dropbox (http://www.metalworking.com). Direct e-mail to me
won't work -- there is a size limit on incoming e-mail which would
bounce it.

Will do, although it will be hard to see that the bottom of the slot is
spherical versus cylindrical.

That was not what I was trying to determine. I just wanted to
see what it looked like so I could tell whether it felt Clausing-made to
me.

OK.


By the way, I looked at the Armstrong website, and the rocker I bought
was not made by Armstrong, although it looks to be interchangeable with
Armstrong. What I have is marked with a flattened diamond and the
number "10". Any idea who makes or made this?

No clue -- unless that is an older Armstrong. The number of
toolpost parts which they currently make is a lot fewer than they used
to make. Everybody is going Aloris style or equivalent.

One assumes that the name somehow involved or implied the word "diamond".

I don't find anything useful with a Google search using the
words Diamond and toolpost. Actually, I find mostly woodworking tools
in the first hits. :-)

That was my experience too. But I've seen that trademark before on
tools.


O.K. But the slotted version is not shown in the manual
drawings for the 5418 at least. Can you find drawings showing the
slotted version in your manual?

All drawings I have show the dished washer as well. My suspicion is
that the slotted washer is a later twist, perhaps late production, or
perhaps from a later model retrofitted to the 5914.

Or even from some other brand of lathe entirely. All I really know is
that the post itself looks like what's in the Clausing manual, and that
the washer was not made by Armstrong.

O.K. But the post is a very common design -- or at least was
back then.

Maybe the cheap fix is to buy an Armstrong washer and rocker to fit the
existing lantern post. J&L carries Armstrong toolposts et al.

Or -- to turn a ring to match the rocker which you have?

That would work too.

But the toolpost ring (J&L ART-89423L) is $18 and the rocker
(ART-89443D) is $11, so maybe I'll just buy them.

By the way, their seat radius is 2-7/8 inch, which may well work with
the slotted ring I hav.


I was cutting off about 1" from the 4-jaw chuck jaws. Really
asking too much of such a light duty lathe. :-)

I'll say. Interrupted cut and all.

Actually, I was into the continuous cut point before it failed.

With the new compound top, some other part would fail first, I
think. :-)

I wouldn't make it _too_ strong, as subsequent parts are ever larger and
more expensive to replace.

Well ... it is stronger mostly thanks to the materials which I
was able to find -- a good tough tool steel instead of cheap cast iron.
I wasn't setting out to make it stronger -- that is just what happened. :-)

I think I would have made the replacement out of good quality cast iron,
not steel, so if something is to break in the future, it will be the
T-slot, not the saddle or whatever. Think of the T-Slot as a mechanical
fuse.


Joe Gwinn

On 2008-03-09, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-08, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-07, Joseph Gwinn wrote:

[ ... ]

Use a solid carbide internal threading boring bar?

Compare the price of a solid carbide internal threading tool
ground for left-hand thread 10 TPI Acme to a left-hand Acme tap at 10
TPI. :-)

But the carbide tool has more uses.

Not if if is ground to cut Acme thread profiles at the 10 TPI
size. There is not much else that it can do.

Right.

And solid carbide tools are *expensive*. I've got a 1/2" solid
carbide boring bar with a silver-soldered end which forms the pocket for
an insert (with flats on top and bottom to assure the proper rotational
angle and keep it from squitting out from under the clamp screws), and it
was something like $135.00 on an eBay auction -- and in catalogs it is
well over $200.00, so I figure that I got a deal at that price. And at
least that has replaceable inserts, so I can use it for boring for quite
a while. It is amazing how little chatter you see with as much as 6"
extension of that 1/2" diameter rod. So -- if you could find an Acme
insert, this would be the tool of choice for making internal threads,
except that it is too large to produce a 1/2" Acme -- and based on other
information later on, I think that the leadscrew in question is smaller
than 1/2". Hmm ... let me go down and check on that before it gets too
late.

O.K. The spare compound has a 3/8-10 Acme leadscrew. Now how
much can you do with that and a between centers bar? A 1/8" tool bit
would not have *any* meat around it after leaving clearance for the
threads. Let's see -- total height of thread is 0.060" for 10 TPI,
times 2 = 0.120" subtracted from major diameter of 0.375 gives us
0.255". For a rod to fit into that, with a transverse square broached
1/8" hole leaves us 0.065" total wall thickness -- not much for a
setscrew to hold the bit -- and that leaves no clearance for the chips or
for withdrawing from the thread between passes.

And 3/8-10 Acme is *not* a standard thread -- even right-hand,
and at least the compound leadscrew (unlike the cross-slide) is a
right-hand thread.

No -- I think that I would turn the needed thread in drill rod,
cut flutes, harden and draw it, and grind the flutes to sharpen it.

Or, mount the nut on the slide and a bar between centers with HSS
toolbit in the center of the bar, perpendicular to the bar, the bar
passing through the nut. I've seen this setup used for line boring of
bearings on electric motors.

Again -- the bar is likely to be pretty skinny. The minor
diameter for a 1/2" 10 TPI Acme (LH or RH won't make much difference)
for class 2G threads is:

Max: 0.3800"
Min: 0.3594"

so -- with a 3/8" rod, and max diameter you would have 0.0025" clearance
for the chips -- and all other options are less. Anything smaller than
3/8" diameter would be even worse in terms of rigidity (and even windup
of the rod). I don't think that I would want to single-point that
thread.

It would be slow for sure, but the point of holding both ends with
cutter in the center is a substantial increase in rigidity compared to a
bar held from one end only.

And I left out of the calculations the fact that it would have
to be small enough to allow both the bar *and* the projection of the
tool to cut the full thread to slide into the bore before cutting
threads. And if it is *just* right in size, it makes how far you back
out of the thread prior to cranking back for the next pass more
sensitive.

I visualize it as having a small bit held in a cross hole, held by a
perpendicular setscrew. One may need to use a 1.8" bit, such as used
for jewelry lathes.

Covered above -- now that we are down to a 3/8" thread, there is
not even enough meat for this -- complete with about 1/16th inch of
sidewall for the threads for the setscrew. And the setscrew could not
be allowed to stick up above the bar, either.

[ ... ]

Yes -- but how do you adjust the tool protrusion for the
subsequent passes? That is the tricky part, especially with a bar small
enough to clear both the cutting tool and the bar diameter through the
bore. You *do* have to advance the tool out of the bar, you can't do it
with the cross-slide leadscrew.

Correct. The cross-slide does not move during this operation.

By loosening the setscrew and moving the bit, using a depth mike to set
the protrusion as one creeps up on the correct cut depth.

A tricky bit of work -- especially with such a tiny setscrew. I
would rather try making a tap to serve the function.

[ ... ]

The cylinder fits snugly into a hole in the Compound Slide (704-34), and
is held in place by a single setscrew.

I missed that you said "Compound Slide" at first -- which
changes everything. The "Tee" shaped nut is for the main cross-slide,
not the compound. (Just to be sure -- which *is* it which is so loose?
My backlash was in the cross-slide -- the one which always moves at
right angles to the lathe bed, instead of the one which can be set to
different angles depending on need.

O.K. So the hole is a lot shorter than it is in the "Tee"
design and the cylinder is mounted with its axis vertical? That would
interchange with the original Tee -- but would wear a lot faster with
fewer threads engaged.

So it appears - this axis is by far the loosest.

I should measure wear on the screw - perhaps all I need is to replace
the nut.


The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly)
also
on page 30.

No page 30 in my manual. Mine stops at page 20 -- exclusive of
the un-numbered lubrication chart.

Try page 19 in the 5418 manual. Both nuts are shown. The cylinder nut
is DL-471 and the T-shaped bronze nut is 990-069. The nuts on the 5914
look exactly the same.

Oh -- you are talking about the nut for the *compound*, not the
cross-slide. That looks even smaller in the drawings -- perhaps 3/8"
instead of 1/2". I thought that we were talking about the cross-slide
on the carriage, not the compound top slide.

How did we get that far apart?

I've been trying to follow the nomenclature in the Clausing manual, for
better or for worse, even when it seems counter-intuitive. But I
suspect that nomenclature isn't uniform between manufacturers, which is
why I started to give the actual part number as well.

O.K. Let me define *my* terms so we can be talking about the
same thing:

1) The "Longitudinal leadscrew" -- leadscrew under the front lip
of the lathe bed running behind and partially through the apron.

2) The "Saddle" or "Carriage" -- that which moves along the lathe
bed either under control of the leadscrew (when threading) or a
rack under the lip of the bed and a pinion in the apron (the
front of the carriage). The pinion can be turned either by the
handwheel, or by gearing driven by a keyway in the longitudinal
leadscrew.

3) The "cross slide" -- the part which moves at right angles
to the bed via a crank on the top area of the apron, driven
either by hand on the crank, or by gearing inside the apron
driven by the keyway in the longitudinal leadscrew.

4) The "Cross Slide Leadscrew" -- the leadscrew which moves the
cross slide above the carriage. Note that the dial on the cross
slide *may* be calibrated to read twice the actual motion, so it
represents diameter removed instead of radius. This makes sense
since it only moves at right angles to the lathe bed, so it will
always remove twice its motion in diameter from the workpiece.
Whether it reads diameter or radius is at the whim of the
manufacturer -- and you need to check when moving from one lathe
to another to avoid nasty surprises. :-)

5) The "Compound assembly" or just "Compound" -- bolts to the top
of the cross slide with provisions to adjust its angle relative
to the bed. It can move at any one angle depending on setting.

6) The "Compound Assembly Leadscrew" -- Here, the dial is usually
(but not always) set up to read the actual motion, since it can
be operated at any angle -- so it may represent diameter
removed, or length of stock removed, or some combination of the
two.


On the 5914, the slide is flat-topped, not humped.

You mean the compound, not the cross-slide? I wonder why?

In the 5914 manual (page 30), that T-slotted part is flat-topped and is
called the "Tool Post Slide" (704-033), and is dovetailed to the
"Compound Slide" (704-034), which in turn rotates upon the "Cross Slide"
(704-032).

In the 5418 manual (page 19), that same part is humpbacked and is called
simply the "Slide" (C-330), and is dovetailed to the "Lower Compound"
(DL-460), which rotates upon the "Cross Slide" (DL-458).

So, even within Clausing, the nomenclature varies. Thus the confusion.

Thus my listing of my own usage of the terms above -- so we can
talk about the same thing.

And the taper attachment only works with the cross-slide
leadscrew, not the compound leadscrew.


OK. Comparative benefits?

[ ... ]

I would probably prefer the telescoping if I were switching back
and forth a lot between taper and non, but for occasional use I prefer
the non-telescoping (which happens to be what I already have,
simplifying matters.

Sounds like non-telescoping would be best for me as well.

And -- it should cost less, too. :-)

Yep. And now to find one.

It took me two or three years, of following eBay auctions to
find one which I *thought* would work -- and then some time to figure
out how it was supposed to work (and what parts I needed to make to
complete it) once I got it. Later, I got a manual for both it and the
telescoping one and discovered that I was right -- and only slightly off
in one thing -- a washer under the clamp for the "traveling nut" which I
made on the surface grinder to be the right thickness should really have
been bent from the proper sheet steel to this shape (be sure to view
with a fixed pitch font like Courier to avoid distortion of the image):

/|_______/|
// O //
|/ |/
+--------+

Note that the hole designated by the 'O' should be centered in the
bottom plate -- but I would have to make the ASCII drawing much larger
to allow that -- and I still could not keep the scale right, so I'll
leave it as it is.

[ ... ]

Could you do a good set of close-up photos of the ring and drop
them in the dropbox (http://www.metalworking.com). Direct e-mail to me
won't work -- there is a size limit on incoming e-mail which would
bounce it.

Will do, although it will be hard to see that the bottom of the slot is
spherical versus cylindrical.

That was not what I was trying to determine. I just wanted to
see what it looked like so I could tell whether it felt Clausing-made to
me.

OK.

We may no longer need this, if we both agree that it is possible
that it was not a Clausing original.

By the way, I looked at the Armstrong website, and the rocker I bought
was not made by Armstrong, although it looks to be interchangeable with
Armstrong. What I have is marked with a flattened diamond and the
number "10". Any idea who makes or made this?

No clue -- unless that is an older Armstrong. The number of
toolpost parts which they currently make is a lot fewer than they used
to make. Everybody is going Aloris style or equivalent.

One assumes that the name somehow involved or implied the word "diamond".

I don't find anything useful with a Google search using the
words Diamond and toolpost. Actually, I find mostly woodworking tools
in the first hits. :-)

That was my experience too. But I've seen that trademark before on
tools.

O.K. My original thought when "diamond" was mentioned was about
the non-slip texturing of the surface on which the tool holder rests.

[ ... ]

Or even from some other brand of lathe entirely. All I really know is
that the post itself looks like what's in the Clausing manual, and that
the washer was not made by Armstrong.

O.K. But the post is a very common design -- or at least was
back then.

Maybe the cheap fix is to buy an Armstrong washer and rocker to fit the
existing lantern post. J&L carries Armstrong toolposts et al.

Or -- to turn a ring to match the rocker which you have?

That would work too.

But the toolpost ring (J&L ART-89423L) is $18 and the rocker
(ART-89443D) is $11, so maybe I'll just buy them.

By the way, their seat radius is 2-7/8 inch, which may well work with
the slotted ring I hav.

So -- turn a disc of that radius and see how it fits. Perhaps
start oversized so you can creep up on the proper dimension.

[ ... ]

With the new compound top, some other part would fail first, I
think. :-)

I wouldn't make it _too_ strong, as subsequent parts are ever larger and
more expensive to replace.

Well ... it is stronger mostly thanks to the materials which I
was able to find -- a good tough tool steel instead of cheap cast iron.
I wasn't setting out to make it stronger -- that is just what happened. :-)

I think I would have made the replacement out of good quality cast iron,
not steel, so if something is to break in the future, it will be the
T-slot, not the saddle or whatever. Think of the T-Slot as a mechanical
fuse.

At the time -- cast iron was not available to me. I was working
with scrap available at the local shop at work (along with the tools to
shape it) and had no idea where to order such things.

Now -- it looks so much nicer than the original (thanks to the
surface grinder final finish) that I am reluctant to change it -- and I
don't use that lathe any more, anyway. (There are enough other problems
so it is not worth the effort, and it is in the cellar, not the garage
which became the shop. For things that small, I have the 5" CNC lathe
by Emco-Maier which is a much better machine than the old
Atlas/Craftsman with the bronze spindle bearings and the worn
flat top ways.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-03-09, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-08, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-07, Joseph Gwinn wrote:

[ ... ]

Use a solid carbide internal threading boring bar?

Compare the price of a solid carbide internal threading tool
ground for left-hand thread 10 TPI Acme to a left-hand Acme tap at 10
TPI. :-)

But the carbide tool has more uses.

Not if if is ground to cut Acme thread profiles at the 10 TPI
size. There is not much else that it can do.

Right.

And solid carbide tools are *expensive*. I've got a 1/2" solid
carbide boring bar with a silver-soldered end which forms the pocket for
an insert (with flats on top and bottom to assure the proper rotational
angle and keep it from squitting out from under the clamp screws), and it
was something like $135.00 on an eBay auction -- and in catalogs it is
well over $200.00, so I figure that I got a deal at that price. And at
least that has replaceable inserts, so I can use it for boring for quite
a while. It is amazing how little chatter you see with as much as 6"
extension of that 1/2" diameter rod. So -- if you could find an Acme
insert, this would be the tool of choice for making internal threads,
except that it is too large to produce a 1/2" Acme -- and based on other
information later on, I think that the leadscrew in question is smaller
than 1/2". Hmm ... let me go down and check on that before it gets too
late.

Solid Criterion or Criterion-like bars turn up used around here for a
few dollars, but usually need some cleanup with a grinder.

And the Chinese are learning how to make these as well.


O.K. The spare compound has a 3/8-10 Acme leadscrew. Now how
much can you do with that and a between centers bar? A 1/8" tool bit
would not have *any* meat around it after leaving clearance for the
threads. Let's see -- total height of thread is 0.060" for 10 TPI,
times 2 = 0.120" subtracted from major diameter of 0.375 gives us
0.255". For a rod to fit into that, with a transverse square broached
1/8" hole leaves us 0.065" total wall thickness -- not much for a
setscrew to hold the bit -- and that leaves no clearance for the chips or
for withdrawing from the thread between passes.

There are smaller bits than 0.125", which is far larger than needed to
cut a 10 tpi acme thread. In round numbers, if the pitch is 0.100",
then the tool width is something like 0.060", which can be made from a
piece of 0.1" drill rod, leaving ample space for a small setscrew.


And 3/8-10 Acme is *not* a standard thread -- even right-hand,
and at least the compound leadscrew (unlike the cross-slide) is a
right-hand thread.

No -- I think that I would turn the needed thread in drill rod,
cut flutes, harden and draw it, and grind the flutes to sharpen it.

This is indeed the traditional approach.


Or, mount the nut on the slide and a bar between centers with HSS
toolbit in the center of the bar, perpendicular to the bar, the bar
passing through the nut. I've seen this setup used for line boring
of bearings on electric motors.

Again -- the bar is likely to be pretty skinny. The minor
diameter for a 1/2" 10 TPI Acme (LH or RH won't make much difference)
for class 2G threads is:

Max: 0.3800"
Min: 0.3594"

so -- with a 3/8" rod, and max diameter you would have 0.0025"
clearance
for the chips -- and all other options are less. Anything smaller than
3/8" diameter would be even worse in terms of rigidity (and even windup
of the rod). I don't think that I would want to single-point that
thread.

The center of the rod could be turned down for chip clearance without
badly reducing the stiffness.


It would be slow for sure, but the point of holding both ends with
cutter in the center is a substantial increase in rigidity compared to a
bar held from one end only.

And I left out of the calculations the fact that it would have
to be small enough to allow both the bar *and* the projection of the
tool to cut the full thread to slide into the bore before cutting
threads. And if it is *just* right in size, it makes how far you back
out of the thread prior to cranking back for the next pass more
sensitive.

I visualize it as having a small bit held in a cross hole, held by a
perpendicular setscrew. One may need to use a 1/8" bit, such as used
for jewelry lathes.

Covered above -- now that we are down to a 3/8" thread, there is
not even enough meat for this -- complete with about 1/16th inch of
sidewall for the threads for the setscrew. And the setscrew could not
be allowed to stick up above the bar, either.

Also covered above. Jewelers and clockmakers do this kind of stuff all
the time - same idea, but in miniature.


Yes -- but how do you adjust the tool protrusion for the
subsequent passes? That is the tricky part, especially with a bar small
enough to clear both the cutting tool and the bar diameter through the
bore. You *do* have to advance the tool out of the bar, you can't do it
with the cross-slide leadscrew.

Correct. The cross-slide does not move during this operation.

By loosening the setscrew and moving the bit, using a depth mike to set
the protrusion as one creeps up on the correct cut depth.

A tricky bit of work -- especially with such a tiny setscrew. I
would rather try making a tap to serve the function.

Not that tricky. But I'm coming around to the make-a-tap school as
well. One can also order taps made. I don't recall the price, but it
wasn't astronomical. This was discussed on RCM a while ago.


The cylinder fits snugly into a hole in the Compound Slide (704-34),
and is held in place by a single setscrew.

I missed that you said "Compound Slide" at first -- which
changes everything. The "Tee" shaped nut is for the main cross-slide,
not the compound. (Just to be sure -- which *is* it which is so loose?
My backlash was in the cross-slide -- the one which always moves at
right angles to the lathe bed, instead of the one which can be set to
different angles depending on need.

The looser axis is the one closest to the T-Slot, and which can be set
at various angles to the lathe bed ways.

The axis perpendicular to the bed ways is also loose, but far less so.


O.K. So the hole is a lot shorter than it is in the "Tee"
design and the cylinder is mounted with its axis vertical? That would
interchange with the original Tee -- but would wear a lot faster with
fewer threads engaged.

So it appears - this axis is by far the loosest.

I should measure wear on the screw - perhaps all I need is to replace
the nut.


The T-shaped nut is part number 5900-37 (Cross Slide Nut Assembly)
also on page 30.

No page 30 in my manual. Mine stops at page 20 -- exclusive of
the un-numbered lubrication chart.

Try page 19 in the 5418 manual. Both nuts are shown. The cylinder nut
is DL-471 and the T-shaped bronze nut is 990-069. The nuts on the 5914
look exactly the same.

Oh -- you are talking about the nut for the *compound*, not the
cross-slide. That looks even smaller in the drawings -- perhaps 3/8"
instead of 1/2". I thought that we were talking about the cross-slide
on the carriage, not the compound top slide.

How did we get that far apart?

I've been trying to follow the nomenclature in the Clausing manual, for
better or for worse, even when it seems counter-intuitive. But I
suspect that nomenclature isn't uniform between manufacturers, which is
why I started to give the actual part number as well.

O.K. Let me define *my* terms so we can be talking about the
same thing:

1) The "Longitudinal leadscrew" -- leadscrew under the front lip
of the lathe bed running behind and partially through the apron.

2) The "Saddle" or "Carriage" -- that which moves along the lathe
bed either under control of the leadscrew (when threading) or a
rack under the lip of the bed and a pinion in the apron (the
front of the carriage). The pinion can be turned either by the
handwheel, or by gearing driven by a keyway in the longitudinal
leadscrew.

3) The "cross slide" -- the part which moves at right angles
to the bed via a crank on the top area of the apron, driven
either by hand on the crank, or by gearing inside the apron
driven by the keyway in the longitudinal leadscrew.

4) The "Cross Slide Leadscrew" -- the leadscrew which moves the
cross slide above the carriage. Note that the dial on the cross
slide *may* be calibrated to read twice the actual motion, so it
represents diameter removed instead of radius. This makes sense
since it only moves at right angles to the lathe bed, so it will
always remove twice its motion in diameter from the workpiece.
Whether it reads diameter or radius is at the whim of the
manufacturer -- and you need to check when moving from one lathe
to another to avoid nasty surprises. :-)

5) The "Compound assembly" or just "Compound" -- bolts to the top
of the cross slide with provisions to adjust its angle relative
to the bed. It can move at any one angle depending on setting.

6) The "Compound Assembly Leadscrew" -- Here, the dial is usually
(but not always) set up to read the actual motion, since it can
be operated at any angle -- so it may represent diameter
removed, or length of stock removed, or some combination of the
two.

It's a logical system for sure. But honored in the breech, as discussed
below. This is why I try to say how far from the T-slot or bed way an
item is.


On the 5914, the slide is flat-topped, not humped.

You mean the compound, not the cross-slide? I wonder why?

In the 5914 manual (page 30), that T-slotted part is flat-topped and is
called the "Tool Post Slide" (704-033), and is dovetailed to the
"Compound Slide" (704-034), which in turn rotates upon the "Cross Slide"
(704-032).

In the 5418 manual (page 19), that same part is humpbacked and is called
simply the "Slide" (C-330), and is dovetailed to the "Lower Compound"
(DL-460), which rotates upon the "Cross Slide" (DL-458).

So, even within Clausing, the nomenclature varies. Thus the confusion.

Thus my listing of my own usage of the terms above -- so we can
talk about the same thing.

And the taper attachment only works with the cross-slide
leadscrew, not the compound leadscrew.

Yes. Makes sense, and the drawings support this. Any you have one and
can look at it.


OK. Comparative benefits?

[ ... ]

I would probably prefer the telescoping if I were switching back
and forth a lot between taper and non, but for occasional use I prefer
the non-telescoping (which happens to be what I already have,
simplifying matters.

Sounds like non-telescoping would be best for me as well.

And -- it should cost less, too. :-)

Yep. And now to find one.

It took me two or three years, of following eBay auctions to
find one which I *thought* would work -- and then some time to figure
out how it was supposed to work (and what parts I needed to make to
complete it) once I got it. Later, I got a manual for both it and the
telescoping one and discovered that I was right -- and only slightly off
in one thing -- a washer under the clamp for the "traveling nut" which I
made on the surface grinder to be the right thickness should really have
been bent from the proper sheet steel to this shape (be sure to view
with a fixed pitch font like Courier to avoid distortion of the image):

/|_______/|
// O //
|/ |/
+--------+

Note that the hole designated by the 'O' should be centered in the
bottom plate -- but I would have to make the ASCII drawing much larger
to allow that -- and I still could not keep the scale right, so I'll
leave it as it is.

I assume that anti-rotation is the intent, and that one could make this
washer with a vertical mill as well.


Could you do a good set of close-up photos of the ring and drop
them in the dropbox (http://www.metalworking.com). Direct e-mail to me
won't work -- there is a size limit on incoming e-mail which would
bounce it.

Will do, although it will be hard to see that the bottom of the slot is
spherical versus cylindrical.

That was not what I was trying to determine. I just wanted to
see what it looked like so I could tell whether it felt Clausing-made to
me.

OK.

We may no longer need this, if we both agree that it is possible
that it was not a Clausing original.

OK. Yes - no proof either way.

It would make sense for Clausing to buy the toolpost assembly, versus
making it themselves.


By the way, I looked at the Armstrong website, and the rocker I
bought
was not made by Armstrong, although it looks to be interchangeable
with
Armstrong. What I have is marked with a flattened diamond and the
number "10". Any idea who makes or made this?

No clue -- unless that is an older Armstrong. The number of
toolpost parts which they currently make is a lot fewer than they used
to make. Everybody is going Aloris style or equivalent.

One assumes that the name somehow involved or implied the word
"diamond".

I don't find anything useful with a Google search using the
words Diamond and toolpost. Actually, I find mostly woodworking tools
in the first hits. :-)

That was my experience too. But I've seen that trademark before on
tools.

O.K. My original thought when "diamond" was mentioned was about
the non-slip texturing of the surface on which the tool holder rests.

It has those to, but this is clearly a trademark symbol, not a
functional feature.

I'm going to Aloris as well.


Or even from some other brand of lathe entirely. All I really know is
that the post itself looks like what's in the Clausing manual, and that
the washer was not made by Armstrong.

O.K. But the post is a very common design -- or at least was
back then.

Maybe the cheap fix is to buy an Armstrong washer and rocker to fit the
existing lantern post. J&L carries Armstrong toolposts et al.

Or -- to turn a ring to match the rocker which you have?

That would work too.

But the toolpost ring (J&L ART-89423L) is $18 and the rocker
(ART-89443D) is $11, so maybe I'll just buy them.

By the way, their seat radius is 2-7/8 inch, which may well work with
the slotted ring I hav.

So -- turn a disc of that radius and see how it fits. Perhaps
start oversized so you can creep up on the proper dimension.

Yep.


With the new compound top, some other part would fail first, I
think. :-)

I wouldn't make it _too_ strong, as subsequent parts are ever larger and
more expensive to replace.

Well ... it is stronger mostly thanks to the materials which I
was able to find -- a good tough tool steel instead of cheap cast iron.
I wasn't setting out to make it stronger -- that is just what happened.
:-)

I think I would have made the replacement out of good quality cast iron,
not steel, so if something is to break in the future, it will be the
T-slot, not the saddle or whatever. Think of the T-Slot as a mechanical
fuse.

At the time -- cast iron was not available to me. I was working
with scrap available at the local shop at work (along with the tools to
shape it) and had no idea where to order such things.

Now -- it looks so much nicer than the original (thanks to the
surface grinder final finish) that I am reluctant to change it -- and I
don't use that lathe any more, anyway. (There are enough other problems
so it is not worth the effort, and it is in the cellar, not the garage
which became the shop. For things that small, I have the 5" CNC lathe
by Emco-Maier which is a much better machine than the old
Atlas/Craftsman with the bronze spindle bearings and the worn
flat top ways.

OK. That makes sense.

I suppose I will outgrow the Clausing someday, but it won't be that soon.

Joe Gwinn

On 2008-03-10, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-09, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-08, Joseph Gwinn wrote:

[ ... ]

But the carbide tool has more uses.

Not if if is ground to cut Acme thread profiles at the 10 TPI
size. There is not much else that it can do.

Right.

And solid carbide tools are *expensive*. I've got a 1/2" solid
carbide boring bar with a silver-soldered end which forms the pocket for
an insert (with flats on top and bottom to assure the proper rotational
angle and keep it from squitting out from under the clamp screws), and it
was something like $135.00 on an eBay auction -- and in catalogs it is
well over $200.00, so I figure that I got a deal at that price. And at
least that has replaceable inserts, so I can use it for boring for quite
a while. It is amazing how little chatter you see with as much as 6"
extension of that 1/2" diameter rod. So -- if you could find an Acme
insert, this would be the tool of choice for making internal threads,
except that it is too large to produce a 1/2" Acme -- and based on other
information later on, I think that the leadscrew in question is smaller
than 1/2". Hmm ... let me go down and check on that before it gets too
late.

Solid Criterion or Criterion-like bars turn up used around here for a
few dollars, but usually need some cleanup with a grinder.

O.K. I wish that *I* could come up with such steals.

And the Chinese are learning how to make these as well.

But -- are they learning to make them *well*?

O.K. The spare compound has a 3/8-10 Acme leadscrew. Now how
much can you do with that and a between centers bar? A 1/8" tool bit
would not have *any* meat around it after leaving clearance for the
threads. Let's see -- total height of thread is 0.060" for 10 TPI,
times 2 = 0.120" subtracted from major diameter of 0.375 gives us
0.255". For a rod to fit into that, with a transverse square broached
1/8" hole leaves us 0.065" total wall thickness -- not much for a
setscrew to hold the bit -- and that leaves no clearance for the chips or
for withdrawing from the thread between passes.

There are smaller bits than 0.125", which is far larger than needed to
cut a 10 tpi acme thread. In round numbers, if the pitch is 0.100",
then the tool width is something like 0.060", which can be made from a
piece of 0.1" drill rod, leaving ample space for a small setscrew.

With round, you have the problem of rotational positioning which is
locked in nicely with square tool bit. Of course, you could grind a
flat on top prior to grinding the Acme profile on the end.

[ ... ]

No -- I think that I would turn the needed thread in drill rod,
cut flutes, harden and draw it, and grind the flutes to sharpen it.

This is indeed the traditional approach.

For good reason with smaller internal threads.


[ ... ]

so -- with a 3/8" rod, and max diameter you would have 0.0025"
clearance
for the chips -- and all other options are less. Anything smaller than
3/8" diameter would be even worse in terms of rigidity (and even windup
of the rod). I don't think that I would want to single-point that
thread.

The center of the rod could be turned down for chip clearance without
badly reducing the stiffness.

As long as you have the diameter small enough to fit into the
pre-threading bore. And since it turns out that the thread is a 3/8",
the bore is noticeably smaller.

Hmm ... since it is also a right-hand thread -- can I find a
3/8-10 standard thread to use as a roughing tap? Hmm ... looks as
though that is a special, too. I guess that we make both the roughing
and finishing tap.

[ ... ]

I visualize it as having a small bit held in a cross hole, held by a
perpendicular setscrew. One may need to use a 1/8" bit, such as used
for jewelry lathes.

Covered above -- now that we are down to a 3/8" thread, there is
not even enough meat for this -- complete with about 1/16th inch of
sidewall for the threads for the setscrew. And the setscrew could not
be allowed to stick up above the bar, either.

Also covered above. Jewelers and clockmakers do this kind of stuff all
the time - same idea, but in miniature.

I could picture them doing it for small boring, but not for
internal threading, since jeweler's lathes typically don't have power
feed, let alone threading feeds.

[ ... ]

By loosening the setscrew and moving the bit, using a depth mike to set
the protrusion as one creeps up on the correct cut depth.

A tricky bit of work -- especially with such a tiny setscrew. I
would rather try making a tap to serve the function.

Not that tricky. But I'm coming around to the make-a-tap school as
well. One can also order taps made. I don't recall the price, but it
wasn't astronomical. This was discussed on RCM a while ago.

Yes -- it all depends on how many of the threads you need to
cut.

[ ... ]

I missed that you said "Compound Slide" at first -- which
changes everything. The "Tee" shaped nut is for the main cross-slide,
not the compound. (Just to be sure -- which *is* it which is so loose?
My backlash was in the cross-slide -- the one which always moves at
right angles to the lathe bed, instead of the one which can be set to
different angles depending on need.

The looser axis is the one closest to the T-Slot, and which can be set
at various angles to the lathe bed ways.

O.K.

The axis perpendicular to the bed ways is also loose, but far less so.

While my compound leadscrew was quite tight (and still is),
while the cross-slide was the one with 0.075" backlash (3/4 of a turn of
the crank).

[ ... ]

Oh -- you are talking about the nut for the *compound*, not the
cross-slide. That looks even smaller in the drawings -- perhaps 3/8"
instead of 1/2". I thought that we were talking about the cross-slide
on the carriage, not the compound top slide.

How did we get that far apart?

I've been trying to follow the nomenclature in the Clausing manual, for
better or for worse, even when it seems counter-intuitive. But I
suspect that nomenclature isn't uniform between manufacturers, which is
why I started to give the actual part number as well.

O.K. Let me define *my* terms so we can be talking about the
same thing:

[ ... ]

It's a logical system for sure. But honored in the breech, as discussed
below. This is why I try to say how far from the T-slot or bed way an
item is.

O.K. Most of the "breech" which I have experienced was in UK
references to lathes -- which would also call a 12" lathe (like my 5418
or your 5914) a 6" lathe -- rating it by the radius from the center of
the spindle to the lathe bed.

They would also be likely to call a "compound" a "top-slide" --
in part because some common lathes had the compound only as an optional
fitting, not as a standard part of the lathe.

On the 5914, the slide is flat-topped, not humped.

You mean the compound, not the cross-slide? I wonder why?

In the 5914 manual (page 30), that T-slotted part is flat-topped and is
called the "Tool Post Slide" (704-033), and is dovetailed to the
"Compound Slide" (704-034), which in turn rotates upon the "Cross Slide"
(704-032).

In the 5418 manual (page 19), that same part is humpbacked and is called
simply the "Slide" (C-330), and is dovetailed to the "Lower Compound"
(DL-460), which rotates upon the "Cross Slide" (DL-458).

So, even within Clausing, the nomenclature varies. Thus the confusion.

O.K. if you are in doubt as to the correct term -- *ask* so we
can know that there is a possibility of difference.

Thus my listing of my own usage of the terms above -- so we can
talk about the same thing.

And the taper attachment only works with the cross-slide
leadscrew, not the compound leadscrew.

Yes. Makes sense, and the drawings support this. Any you have one and
can look at it.

That does help -- but it would have been nice to have the manual
pages too as I was trying to make sense of what was missing.

[ ... ]

Yep. And now to find one.

It took me two or three years, of following eBay auctions to
find one which I *thought* would work -- and then some time to figure
out how it was supposed to work (and what parts I needed to make to
complete it) once I got it. Later, I got a manual for both it and the
telescoping one and discovered that I was right -- and only slightly off
in one thing -- a washer under the clamp for the "traveling nut" which I
made on the surface grinder to be the right thickness should really have
been bent from the proper sheet steel to this shape (be sure to view
with a fixed pitch font like Courier to avoid distortion of the image):

/|_______/|
// O //
|/ |/
+--------+

Note that the hole designated by the 'O' should be centered in the
bottom plate -- but I would have to make the ASCII drawing much larger
to allow that -- and I still could not keep the scale right, so I'll
leave it as it is.

I assume that anti-rotation is the intent, and that one could make this
washer with a vertical mill as well.

The primary function is spacing the traveling nut down from the
bottom of the cross slide -- especially when the clamp is tightened, so
you don't have the leadscrew bent up at the tail and getting tighter the
closer to the nut the handwheel gets.

Remember that the traveling nut is shaped like a narrow but tall
quonset hut, and has a square bar bent into a very long and narrow 'U'
brazed to the bottom. The bar is inset into the base of the hut to
define the width like this (view with Courier again):

/// ///
____/// ///
/ /\/ /// -- part of long 'U' shape. U-turn is at the
/ / \ /// upper right and cut off in the drawing
/__ / \//
/ \ /|
/ () \ // -- this is the nut, and the top is not a meeting
/__ __\// of planes as shown, but rather a smooth curve
|__|__|__|/ which I can't draw with ASCII. Also the hole
shows as way too small.


Anyway -- the nut is shown upside down (for ease of drawing) and
the washer from above (also shown upside down) reaches down beside the
'U' while the thickness of the washer holds the centerline of the nut's
thread at the right distance below the cross-slide itself. (And the
normal tail cover of the cross-slide is replaced by a very long one with
a slot in it which extends over the follower on the taper bar.

Below the washer and the 'U' bar is a nut which is round, with a
pair of steps milled to either side of the threaded hole. This extends
down between the arms of the 'U' and prevents the nut from turning. A
square-headed screw (made to match the wrench which comes with the lathe
and the various other square-headed screws as part of the taper
attachment) pulls it up tight against the 'U' and the bent winged washer
when you wish to lock the nut to the cross slide for normal turning
using the leadscrew. When turning tapers, this is loosened, and another
square-headed screw is tightened down to lock the follower which
straddles the taper bar to the extension of the tail of the cross-slide,
and this pushes the tool back and forth instead of the leadscrew. The
taper bar pivots on a block which slides in dovetails on an extension
bolted to the back of the lathe carriage, and which normally travels
with the carriage -- until you clamp an extension towards the tailstock
to grip the back way of the bed so it stays stationary and the taper bar
(if not set parallel to the ways) will move the block and the
cross-slide back and forth as the carriage moves along the bed.

[ ... ]

I don't find anything useful with a Google search using the
words Diamond and toolpost. Actually, I find mostly woodworking tools
in the first hits. :-)

That was my experience too. But I've seen that trademark before on
tools.

O.K. My original thought when "diamond" was mentioned was about
the non-slip texturing of the surface on which the tool holder rests.

It has those to, but this is clearly a trademark symbol, not a
functional feature.

Understood.

I'm going to Aloris as well.

The better way for almost everything. Unless you get to one of
those really expensive toolposts which let the tool holders lock at 15
degree intervals. :-)

[ ... 6x18" Atlas/Craftsman lathe ... ]

I think I would have made the replacement out of good quality cast iron,
not steel, so if something is to break in the future, it will be the
T-slot, not the saddle or whatever. Think of the T-Slot as a mechanical
fuse.

At the time -- cast iron was not available to me. I was working
with scrap available at the local shop at work (along with the tools to
shape it) and had no idea where to order such things.

Now -- it looks so much nicer than the original (thanks to the
surface grinder final finish) that I am reluctant to change it -- and I
don't use that lathe any more, anyway. (There are enough other problems
so it is not worth the effort, and it is in the cellar, not the garage
which became the shop. For things that small, I have the 5" CNC lathe
by Emco-Maier which is a much better machine than the old
Atlas/Craftsman with the bronze spindle bearings and the worn
flat top ways.

OK. That makes sense.

I suppose I will outgrow the Clausing someday, but it won't be that soon.

I don't think that I will -- unless someone gives me a Monarch
10EE or a Hardinge toolroom lathe -- and even so, I would probably keep
this for the turret and just keep the turret set up full time, instead
of the tailstock being set up most of the time.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

In article ,
"DoN. Nichols" wrote:

On 2008-03-10, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-09, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-08, Joseph Gwinn wrote:

[ ... ]

But the carbide tool has more uses.

Not if if is ground to cut Acme thread profiles at the 10 TPI
size. There is not much else that it can do.

Right.

And solid carbide tools are *expensive*. I've got a 1/2" solid
carbide boring bar with a silver-soldered end which forms the pocket for
an insert (with flats on top and bottom to assure the proper rotational
angle and keep it from squitting out from under the clamp screws), and it
was something like $135.00 on an eBay auction -- and in catalogs it is
well over $200.00, so I figure that I got a deal at that price. And at
least that has replaceable inserts, so I can use it for boring for quite
a while. It is amazing how little chatter you see with as much as 6"
extension of that 1/2" diameter rod. So -- if you could find an Acme
insert, this would be the tool of choice for making internal threads,
except that it is too large to produce a 1/2" Acme -- and based on other
information later on, I think that the leadscrew in question is smaller
than 1/2". Hmm ... let me go down and check on that before it gets too
late.

Solid Criterion or Criterion-like bars turn up used around here for a
few dollars, but usually need some cleanup with a grinder.

O.K. I wish that *I* could come up with such steals.

It's a city thing, as we live off the residue of what had been a
technological civilization.


And the Chinese are learning how to make these as well.

But -- are they learning to make them *well*?

Not yet, but they will soon enough. You remember when Made in Japan
meant junk. Now it's the good stuff.


O.K. The spare compound has a 3/8-10 Acme leadscrew. Now how
much can you do with that and a between centers bar? A 1/8" tool bit
would not have *any* meat around it after leaving clearance for the
threads. Let's see -- total height of thread is 0.060" for 10 TPI,
times 2 = 0.120" subtracted from major diameter of 0.375 gives us
0.255". For a rod to fit into that, with a transverse square broached
1/8" hole leaves us 0.065" total wall thickness -- not much for a
setscrew to hold the bit -- and that leaves no clearance for the chips or
for withdrawing from the thread between passes.

There are smaller bits than 0.125", which is far larger than needed to
cut a 10 tpi acme thread. In round numbers, if the pitch is 0.100",
then the tool width is something like 0.060", which can be made from a
piece of 0.1" drill rod, leaving ample space for a small setscrew.

With round, you have the problem of rotational positioning which is
locked in nicely with square tool bit. Of course, you could grind a
flat on top prior to grinding the Acme profile on the end.

Well, file a flat, before hardening.


so -- with a 3/8" rod, and max diameter you would have 0.0025"
clearance
for the chips -- and all other options are less. Anything smaller
than
3/8" diameter would be even worse in terms of rigidity (and even
windup
of the rod). I don't think that I would want to single-point that
thread.

The center of the rod could be turned down for chip clearance without
badly reducing the stiffness.

As long as you have the diameter small enough to fit into the
pre-threading bore. And since it turns out that the thread is a 3/8",
the bore is noticeably smaller.

Hmm ... since it is also a right-hand thread -- can I find a
3/8-10 standard thread to use as a roughing tap? Hmm ... looks as
though that is a special, too. I guess that we make both the roughing
and finishing tap.

Or throw the towel in, and just buy the damn nut from Clausing.


I visualize it as having a small bit held in a cross hole, held by a
perpendicular setscrew. One may need to use a 1/8" bit, such as used
for jewelry lathes.

Covered above -- now that we are down to a 3/8" thread, there is
not even enough meat for this -- complete with about 1/16th inch of
sidewall for the threads for the setscrew. And the setscrew could not
be allowed to stick up above the bar, either.

Also covered above. Jewelers and clockmakers do this kind of stuff all
the time - same idea, but in miniature.

I could picture them doing it for small boring, but not for
internal threading, since jeweler's lathes typically don't have power
feed, let alone threading feeds.

All we want are their bits, not their lathes.

Jewelers lathes are set up as for woodworking, but writ small.


The axis perpendicular to the bed ways is also loose, but far less so.

While my compound leadscrew was quite tight (and still is),
while the cross-slide was the one with 0.075" backlash (3/4 of a turn of
the crank).

Wonder why. Demands of production, I sup[pose.


Oh -- you are talking about the nut for the *compound*, not the
cross-slide. That looks even smaller in the drawings -- perhaps 3/8"
instead of 1/2". I thought that we were talking about the cross-slide
on the carriage, not the compound top slide.

How did we get that far apart?

I've been trying to follow the nomenclature in the Clausing manual, for
better or for worse, even when it seems counter-intuitive. But I
suspect that nomenclature isn't uniform between manufacturers, which is
why I started to give the actual part number as well.

O.K. Let me define *my* terms so we can be talking about the
same thing:

[ ... ]

It's a logical system for sure. But honored in the breech, as discussed
below. This is why I try to say how far from the T-slot or bed way an
item is.

O.K. Most of the "breech" which I have experienced was in UK
references to lathes -- which would also call a 12" lathe (like my 5418
or your 5914) a 6" lathe -- rating it by the radius from the center of
the spindle to the lathe bed.

They would also be likely to call a "compound" a "top-slide" --
in part because some common lathes had the compound only as an optional
fitting, not as a standard part of the lathe.

Ahh. Interestingly, the Dorian Tool catalog of toolposts has an
annotated drawing of a lathe naming the various parts of said lathe.


On the 5914, the slide is flat-topped, not humped.

You mean the compound, not the cross-slide? I wonder why?

In the 5914 manual (page 30), that T-slotted part is flat-topped and is
called the "Tool Post Slide" (704-033), and is dovetailed to the
"Compound Slide" (704-034), which in turn rotates upon the "Cross Slide"
(704-032).

In the 5418 manual (page 19), that same part is humpbacked and is called
simply the "Slide" (C-330), and is dovetailed to the "Lower Compound"
(DL-460), which rotates upon the "Cross Slide" (DL-458).

So, even within Clausing, the nomenclature varies. Thus the confusion.

O.K. if you are in doubt as to the correct term -- *ask* so we
can know that there is a possibility of difference.

Yep. Well, describe. What we have learned is that the nomenclature is
not uniform, so it is never enough to use the name; one must also
describe the part.


Thus my listing of my own usage of the terms above -- so we can
talk about the same thing.

And the taper attachment only works with the cross-slide
leadscrew, not the compound leadscrew.

Yes. Makes sense, and the drawings support this. Any you have one and
can look at it.

That does help -- but it would have been nice to have the manual
pages too as I was trying to make sense of what was missing.

Someday I'll get a scanner...


Yep. And now to find [a taper attachment].

It took me two or three years, of following eBay auctions to
find one which I *thought* would work -- and then some time to figure
out how it was supposed to work (and what parts I needed to make to
complete it) once I got it. Later, I got a manual for both it and the
telescoping one and discovered that I was right -- and only slightly off
in one thing -- a washer under the clamp for the "traveling nut" which I
made on the surface grinder to be the right thickness should really have
been bent from the proper sheet steel to this shape (be sure to view
with a fixed pitch font like Courier to avoid distortion of the image):

/|_______/|
// O //
|/ |/
+--------+

Note that the hole designated by the 'O' should be centered in the
bottom plate -- but I would have to make the ASCII drawing much larger
to allow that -- and I still could not keep the scale right, so I'll
leave it as it is.

I assume that anti-rotation is the intent, and that one could make this
washer with a vertical mill as well.

The primary function is spacing the traveling nut down from the
bottom of the cross slide -- especially when the clamp is tightened, so
you don't have the leadscrew bent up at the tail and getting tighter the
closer to the nut the handwheel gets.

Remember that the traveling nut is shaped like a narrow but tall
quonset hut, and has a square bar bent into a very long and narrow 'U'
brazed to the bottom. The bar is inset into the base of the hut to
define the width like this (view with Courier again):

/// ///
____/// ///
/ /\/ /// -- part of long 'U' shape. U-turn is at the
/ / \ /// upper right and cut off in the drawing
/__ / \//
/ \ /|
/ () \ // -- this is the nut, and the top is not a meeting
/__ __\// of planes as shown, but rather a smooth curve
|__|__|__|/ which I can't draw with ASCII. Also the hole
shows as way too small.

And the bronze nut is silver brazed to the steel U shape.


Anyway -- the nut is shown upside down (for ease of drawing) and
the washer from above (also shown upside down) reaches down beside the
'U' while the thickness of the washer holds the centerline of the nut's
thread at the right distance below the cross-slide itself. (And the
normal tail cover of the cross-slide is replaced by a very long one with
a slot in it which extends over the follower on the taper bar.

Below the washer and the 'U' bar is a nut which is round, with a
pair of steps milled to either side of the threaded hole. This extends
down between the arms of the 'U' and prevents the nut from turning. A
square-headed screw (made to match the wrench which comes with the lathe
and the various other square-headed screws as part of the taper
attachment) pulls it up tight against the 'U' and the bent winged washer
when you wish to lock the nut to the cross slide for normal turning
using the leadscrew. When turning tapers, this is loosened, and another
square-headed screw is tightened down to lock the follower which
straddles the taper bar to the extension of the tail of the cross-slide,
and this pushes the tool back and forth instead of the leadscrew. The
taper bar pivots on a block which slides in dovetails on an extension
bolted to the back of the lathe carriage, and which normally travels
with the carriage -- until you clamp an extension towards the tailstock
to grip the back way of the bed so it stays stationary and the taper bar
(if not set parallel to the ways) will move the block and the
cross-slide back and forth as the carriage moves along the bed.

I think I visualize this correctly.


I'm going to Aloris as well.

The better way for almost everything. Unless you get to one of
those really expensive toolposts which let the tool holders lock at 15
degree intervals. :-)

I'm sorely tempted by a #22, the theory being that this replaces a
number of individual toolholders, and I'm more interested in flexibility
than simplicity.

I'm also sore tempted by a #5C, which accepts 5C collets and allows me
to utilize all those round shank tools.


I suppose I will outgrow the Clausing someday, but it won't be that soon.

I don't think that I will -- unless someone gives me a Monarch
10EE or a Hardinge toolroom lathe -- and even so, I would probably keep
this for the turret and just keep the turret set up full time, instead
of the tailstock being set up most of the time.

It'll be a few years before the issue becomes salient for me. I'm still
chasing down causes of and cures for chatter.

Joe Gwinn

On 2008-03-11, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

On 2008-03-10, Joseph Gwinn wrote:
In article ,
"DoN. Nichols" wrote:

[ ... ]

And solid carbide tools are *expensive*. I've got a 1/2" solid
carbide boring bar with a silver-soldered end which forms the pocket for

[ ... ]

Solid Criterion or Criterion-like bars turn up used around here for a
few dollars, but usually need some cleanup with a grinder.

O.K. I wish that *I* could come up with such steals.

It's a city thing, as we live off the residue of what had been a
technological civilization.

Well ... I'm pretty close to a city -- but not one engaged in
manufacturing of anything other than legislation. :-)

And the Chinese are learning how to make these as well.

But -- are they learning to make them *well*?

Not yet, but they will soon enough. You remember when Made in Japan
meant junk. Now it's the good stuff.

Oh yes -- I remember my set of butter-steel drill bits. :-) This
was around 1961 or so, IIRC. But since I was driving them with a
hand-cranked eggbeater drill, they still served fairly well for my needs
at the time.

[ ... ]

There are smaller bits than 0.125", which is far larger than needed to
cut a 10 tpi acme thread. In round numbers, if the pitch is 0.100",
then the tool width is something like 0.060", which can be made from a
piece of 0.1" drill rod, leaving ample space for a small setscrew.

With round, you have the problem of rotational positioning which is
locked in nicely with square tool bit. Of course, you could grind a
flat on top prior to grinding the Acme profile on the end.

Well, file a flat, before hardening.

Or -- use my surface grinder to grind the flat -- since I used
the surface grinder to grind the Acme profile with custom relief angles
for the particular thread pitch and diameter which I was cutting. The
final pass was grinding back the tip until it fit the Acme thread gauge
for width.

[ ... ]

The center of the rod could be turned down for chip clearance without
badly reducing the stiffness.

As long as you have the diameter small enough to fit into the
pre-threading bore. And since it turns out that the thread is a 3/8",
the bore is noticeably smaller.

Hmm ... since it is also a right-hand thread -- can I find a
3/8-10 standard thread to use as a roughing tap? Hmm ... looks as
though that is a special, too. I guess that we make both the roughing
and finishing tap.

Or throw the towel in, and just buy the damn nut from Clausing.

Yep. That is what I did with the Tee shaped nut for the
cross-slide.

BTW I think that the "slide" term is sufficiently disambiguated by
prefixing either "cross" (closest to the bed on top of the carriage) or
"top" or "compound" for the compound (top-most slideway).

[ ... ]

Also covered above. Jewelers and clockmakers do this kind of stuff all
the time - same idea, but in miniature.

I could picture them doing it for small boring, but not for
internal threading, since jeweler's lathes typically don't have power
feed, let alone threading feeds.

All we want are their bits, not their lathes.

But you were saying "Jewelers and clockmakers do this kind of
stuff all the time" -- suggesting that "this kind of stuff" meant
internal threading -- and I was pointing out that they were unlikely
to be threading -- internal or external -- on their lathes.

Jewelers lathes are set up as for woodworking, but writ small.

I know -- I have one. I also have the WW collet spindles for
both the Unimat SL-1000 and the Taig/Peatol. Those are really nice for
the kind of work that I do there.

The axis perpendicular to the bed ways is also loose, but far less so.

While my compound leadscrew was quite tight (and still is),
while the cross-slide was the one with 0.075" backlash (3/4 of a turn of
the crank).

Wonder why. Demands of production, I sup[pose.

Certainly. Remember that the lathe had a bed turret, so most
cutting was done with the tooling on the turret. The cross-slide was
power feed and used for parting off -- and probably nothing else -- so
it got used a lot, while the crank on the compound was likely used only
for fine tuning of cutter position vs a bed stop. Probably set up
parallel to the ways.

[ ... ]

O.K. Let me define *my* terms so we can be talking about the
same thing:

[ ... ]

It's a logical system for sure. But honored in the breech, as discussed
below. This is why I try to say how far from the T-slot or bed way an
item is.

O.K. Most of the "breech" which I have experienced was in UK
references to lathes -- which would also call a 12" lathe (like my 5418
or your 5914) a 6" lathe -- rating it by the radius from the center of
the spindle to the lathe bed.

They would also be likely to call a "compound" a "top-slide" --
in part because some common lathes had the compound only as an optional
fitting, not as a standard part of the lathe.

Ahh. Interestingly, the Dorian Tool catalog of toolposts has an
annotated drawing of a lathe naming the various parts of said lathe.

And what names do *they* use? I don't have that catalog.

On the 5914, the slide is flat-topped, not humped.

You mean the compound, not the cross-slide? I wonder why?

In the 5914 manual (page 30), that T-slotted part is flat-topped and is
called the "Tool Post Slide" (704-033), and is dovetailed to the
"Compound Slide" (704-034), which in turn rotates upon the "Cross Slide"
(704-032).

In the 5418 manual (page 19), that same part is humpbacked and is called
simply the "Slide" (C-330), and is dovetailed to the "Lower Compound"
(DL-460), which rotates upon the "Cross Slide" (DL-458).

So, even within Clausing, the nomenclature varies. Thus the confusion.

I think that the "cross slide" is a stable term, and anything
else is presumed to be the compound.

O.K. if you are in doubt as to the correct term -- *ask* so we
can know that there is a possibility of difference.

Yep. Well, describe. What we have learned is that the nomenclature is
not uniform, so it is never enough to use the name; one must also
describe the part.

I still think that "cross slide" is sufficiently unambiguous.

Thus my listing of my own usage of the terms above -- so we can
talk about the same thing.

And the taper attachment only works with the cross-slide
leadscrew, not the compound leadscrew.

Yes. Makes sense, and the drawings support this. Any you have one and
can look at it.

That does help -- but it would have been nice to have the manual
pages too as I was trying to make sense of what was missing.

Someday I'll get a scanner...

Well ... I now have the manuals -- once I knew what to ask
Clausing for. I got a PDF scan of a catalog from the period and then
had model numbers to ask for. (The model number was polished off in
de-rusting what I had, I think -- before I got it.)

[ ... lots of description trimmed ... ]

Remember that the traveling nut is shaped like a narrow but tall
quonset hut, and has a square bar bent into a very long and narrow 'U'
brazed to the bottom. The bar is inset into the base of the hut to
define the width like this (view with Courier again):

/// ///
____/// ///
/ /\/ /// -- part of long 'U' shape. U-turn is at the
/ / \ /// upper right and cut off in the drawing
/__ / \//
/ \ /|
/ () \ // -- this is the nut, and the top is not a meeting
/__ __\// of planes as shown, but rather a smooth curve
|__|__|__|/ which I can't draw with ASCII. Also the hole
shows as way too small.

And the bronze nut is silver brazed to the steel U shape.

Yes.

[ ... more trimmed ... ]

I think I visualize this correctly.


I'm going to Aloris as well.

The better way for almost everything. Unless you get to one of
those really expensive toolposts which let the tool holders lock at 15
degree intervals. :-)

I'm sorely tempted by a #22, the theory being that this replaces a
number of individual toolholders, and I'm more interested in flexibility
than simplicity.

Hmmm ... I would have to dig into the MSC catalog to figure out
a #22.

O.K. I see what it is now. It might be nice for occasional
tasks where a weird angle is needed, but for most purposes, I find the
BXA-16N to handle things nicely, with a pair of holders with straight
ahead mounted tools to cut bevels. The BXA-22 looks like a pain to
re-set in the middle of a task, so having it as the only one is not what
makes sense to me -- kind of like having a 3-in-1 machine where you have
to tear down the milling setup to turn a part needed for completing the
milling. :-)

I'm also sore tempted by a #5C, which accepts 5C collets and allows me
to utilize all those round shank tools.

Hmm ... I've got whatever the holder is which offers a 3MT
socket (matching the tailstock socket) which lets me put in anything
which I can use in the tailstock -- including drill chucks, of course.

I suppose I will outgrow the Clausing someday, but it won't be that soon.

I don't think that I will -- unless someone gives me a Monarch
10EE or a Hardinge toolroom lathe -- and even so, I would probably keep
this for the turret and just keep the turret set up full time, instead
of the tailstock being set up most of the time.

It'll be a few years before the issue becomes salient for me. I'm still
chasing down causes of and cures for chatter.

Interestingly enough, the 5418 does not seem to experience much
chatter.

Enjoy,
DoN.

--
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