wrote in message
...
snip--
It's boring and ID on such piece that had me worried.

Piece of cake!

Once you've used soft jaws with success, you'll wonder how the hell you got
along without them. They are, truly, the magic bullet of lathe work.

I use soft jaws in place of the hardened steel jaws with almost NO
exceptions. I have a set that is bored through for gripping bar stock. It
runs truer than the factory jaws in both concentricity and perpendicularity.

Harold

wrote in message
...
snip--


I see your point, too. OTOH you gotta love the diversity of opinions
on this group :-)

The only problem I have with that concept is that you often get advice that
isn't very good, and if you are asking the question, you may well not be
able to discern good suggestions from those that are troublesome. I face
this problem all the time with well meaning but poorly informed people that
think of themselves as machinists (yet they have no experience in the trade.
Strange!)

In many cases, they've struggled through a tough project and succeeded to
some degree, but don't have a clue that there's much better ways to approach
the problem. There's nothing quite like years of experience, especially
if they're spent running a (commercial) shop, making all of the decisions.

The biggest problem you'll face on an open discussion forum such as this is
the guy that can't resist telling you how to do a job when he doesn't know,
himself. I think it's a guy thing! :-)

Some guys just love to see their name in print.

Harold

On Dec 13, 8:40*pm, wrote:
...
Would steel jaws not do the same?
.
Michael Koblic,

Sure, but they may scratch the finished surface.

jsw

On Wed, 15 Dec 2010 07:09:20 GMT, "Harold & Susan Vordos"
wrote:


wrote in message
.. .
snip--


I see your point, too. OTOH you gotta love the diversity of opinions
on this group :-)

The only problem I have with that concept is that you often get advice that
isn't very good, and if you are asking the question, you may well not be
able to discern good suggestions from those that are troublesome. I face
this problem all the time with well meaning but poorly informed people that
think of themselves as machinists (yet they have no experience in the trade.
Strange!)

In many cases, they've struggled through a tough project and succeeded to
some degree, but don't have a clue that there's much better ways to approach
the problem. There's nothing quite like years of experience, especially
if they're spent running a (commercial) shop, making all of the decisions.

The biggest problem you'll face on an open discussion forum such as this is
the guy that can't resist telling you how to do a job when he doesn't know,
himself. I think it's a guy thing! :-)

Some guys just love to see their name in print.

So, no different from other spheres of life then...:-)

On Wed, 15 Dec 2010 06:56:03 GMT, "Harold & Susan Vordos"
wrote:


wrote in message
.. .
On Tue, 14 Dec 2010 09:48:57 GMT, "Harold & Susan Vordos"
wrote:
snip-

If you're interested in reading a document I prepared years ago,
pertaining
to the use of soft jaws, please ask and I'll provide a link. Not
promoting
myself here, just trying to share what I learned in my years of using soft
jaws.

I am very much interested.

Michael Koblic,
Campbell River, BC

Here's the link.
http://www.chaski.org/homemachinist/...hp?f=44&t=4266

There's a few pictures included, which you may not be able to view unless
you're a registered reader. We used to allow open registration, but Marty
changed board policy a few years ago to deter spamming.

Should you attempt to register, do provide the reasons you'd like access to
the board. Marty approves all registrations.

Good luck! I think you'll find the thread very enlightening.


Thank you. Read and bookmarked. Very helpful not just for the
specifics of soft jaws but also for the general principles.

I re-read all the posts in this thread as well as a thread on another
forum dealing with a similar problem and came up with an idea which:
1) Might solve the problem to some extent
2) Will not tax my limited skills
3) Will not tax my bank account

Following the principles of the soft jaws and the step collet I
thought of attaching a 5/8"+ thick aluminum plate to one of my
faceplates, turn it true and face it. Then turn a recess in the face
of this plate with the ID=OD of my work piece (well, a slip fit).
Clean the inside of the recess as well as the work piece and attach
the work piece inside this recess with double sided sticky tape. This
should allow boring ID and facing of one side of the work piece. If
all my future pieces are turned to exactly the same OD and the face
plate-aluminum plate assembly is kept intact this setup should allow
repeat work.

To be honest I think it was George McDufy who touched on this solution
but did not expand on it.

Meanwhile I shall explore the possibilities of a 5" chuck with
two-component jaws.

Michael Koblic,
Campbell River, BC

Thanks Harold, it's a pleasure reading your concise descriptions and
recommendations from your experience in various aspects of metalworking.

--
WB
..........


"Harold & Susan Vordos" wrote in message
. ..

Here's the link.
http://www.chaski.org/homemachinist/...hp?f=44&t=4266

There's a few pictures included, which you may not be able to view unless
you're a registered reader. We used to allow open registration, but
Marty changed board policy a few years ago to deter spamming.

Should you attempt to register, do provide the reasons you'd like access
to the board. Marty approves all registrations.

Good luck! I think you'll find the thread very enlightening.

Harold

"Wild_Bill" wrote in message
...
Thanks Harold, it's a pleasure reading your concise descriptions and
recommendations from your experience in various aspects of metalworking.

--
WB

Thank you, Bill. I appreciate your kind words, but, most importantly, that
you found value in my comments. There's a lot of expererience backing
those words! :-)

Harold

wrote in message
...
On Wed, 15 Dec 2010 06:56:03 GMT, "Harold & Susan Vordos"
wrote:


wrote in message
. ..
On Tue, 14 Dec 2010 09:48:57 GMT, "Harold & Susan Vordos"
wrote:
snip-

If you're interested in reading a document I prepared years ago,
pertaining
to the use of soft jaws, please ask and I'll provide a link. Not
promoting
myself here, just trying to share what I learned in my years of using
soft
jaws.

I am very much interested.

Michael Koblic,
Campbell River, BC

Here's the link.
http://www.chaski.org/homemachinist/...hp?f=44&t=4266

There's a few pictures included, which you may not be able to view unless
you're a registered reader. We used to allow open registration, but
Marty
changed board policy a few years ago to deter spamming.

Should you attempt to register, do provide the reasons you'd like access
to
the board. Marty approves all registrations.

Good luck! I think you'll find the thread very enlightening.


Thank you. Read and bookmarked. Very helpful not just for the
specifics of soft jaws but also for the general principles.

I re-read all the posts in this thread as well as a thread on another
forum dealing with a similar problem and came up with an idea which:
1) Might solve the problem to some extent
2) Will not tax my limited skills
3) Will not tax my bank account

Following the principles of the soft jaws and the step collet I
thought of attaching a 5/8"+ thick aluminum plate to one of my
faceplates, turn it true and face it. Then turn a recess in the face
of this plate with the ID=OD of my work piece (well, a slip fit).
Clean the inside of the recess as well as the work piece and attach
the work piece inside this recess with double sided sticky tape. This
should allow boring ID and facing of one side of the work piece. If
all my future pieces are turned to exactly the same OD and the face
plate-aluminum plate assembly is kept intact this setup should allow
repeat work.

While the concept appear sound, I think you'll find it doesn't work well.
For one, when you start machining, you'll generate heat---which softens the
adhesive somewhat. You will be very limited to the amount you can remove
per pass.

As you face material that has not been previously machined, upsetting the
surface tends to relieve internal stresses, causing the material to move.
That, couple with the generated heat and the pressure of the cut will most
likely pull the part from the pocket.

Not suggesting it can't work, but I truly believe you'll just exchange one
set of problems for another set of problems.

On a positive note-----many years ago, where I was trained as a machinist
(Sperry Utah Engineering Laboratory), we were the builders of the Sergeant
Guided Missile. The missile had brakes! (Really!)
Being a ballistic missile, and solid propellant, brakes controlled the
trajectory, with an onboard computer (that used ferrite core memory).
Anyway, the bulkhead on which the brake system mounted was a large magnesium
truss. While tolerance wasn't really tight, it was difficult to accomplish
because the truss was easily deformed by holding devices. In the end, in
order to maintain the level of precision required, the faces were held to
the mill table with double sticky tape. Needless to say, cuts were VERY
light, but it provided the required restraint without distorting the part.
It can work, but it's very labor intensive.

Can you be a little specific and tell me exactly what you're trying to
accomplish, and how you start? Type of material, thickness of material,
destination sizes and tolerance, and anything that may flavor the outcome
would be nice to hear. Could be I can offer a solution----or not! :-)

Harold

On Dec 15, 11:38*pm, wrote:
...
Following the principles of the soft jaws and the step collet I
thought of attaching a 5/8"+ thick aluminum plate to one of my
faceplates, turn it true and face it. Then turn a recess in the face
of this plate with the ID=OD of my work piece (well, a slip fit).
Clean the inside of the recess as well as the work piece and attach
the work piece inside this recess with double sided sticky tape. This
should allow boring ID and facing of one side of the work piece. If
all my future pieces are turned to exactly the same OD and the face
plate-aluminum plate assembly is kept intact this setup should allow
repeat work....

Michael Koblic,

You may be remembering a similar custom wooden chuck from Holtzapfel.
There or somewhere I saw a variation with the outer lip slit and
undercut so a large sliding steel ring (hose clamp?) would wedge it
closed on the disk. I think he suggested a mix of pitch and wax,
available now as cross-country ski wax, to further hold the disk. I
use hot melt glue for such tasks, melted with a hot air gun or hair
dryer. So far it's held as long as the work doesn't become too hot to
touch.

My large thin disks are gear or pulley blanks which can tolerate extra
mounting holes, and I have 5C pot collets to hold them.
http://media.photobucket.com/image/p...chine/pot2.jpg

This (see?) second-hand pot collet had been pretty much used up for
custom jobs, so I refurbished it by boring the inside smooth and
turning a matching plug on the side of a thick aluminum disk. After
tapping the aluminum and screwing it to the collet I sawed it into
sections. The steps I've cut are as shallow as 0.020", to hold thin
spacer washers.

Some of the older pot collets have a solid shank and a tapered closer
ring at the OD like the wooden chucks. I'm trying to think of a way to
mount an inside-tapered ring on a face plate such that it would force
pie jaw plates inwards as you tightened them against the faceplate.
Perhaps a large tapered pipe thead like a drain pipe cleanout plug
would hold square while closing the jaws.

jsw

On Thu, 16 Dec 2010 07:32:14 GMT, "Harold & Susan Vordos"
wrote:

[...]

While the concept appear sound, I think you'll find it doesn't work well.
For one, when you start machining, you'll generate heat---which softens the
adhesive somewhat. You will be very limited to the amount you can remove
per pass.

As you face material that has not been previously machined, upsetting the
surface tends to relieve internal stresses, causing the material to move.
That, couple with the generated heat and the pressure of the cut will most
likely pull the part from the pocket.

Not suggesting it can't work, but I truly believe you'll just exchange one
set of problems for another set of problems.

I can't argue with that. Also cannot pretend that it was an original
idea...

[...]

Can you be a little specific and tell me exactly what you're trying to
accomplish, and how you start? Type of material, thickness of material,
destination sizes and tolerance, and anything that may flavor the outcome
would be nice to hear. Could be I can offer a solution----or not! :-)

I don't think I can add much to the OP.
The end result should look something like this:

http://www.flickr.com/photos/27683124@N07/5242609640/

Tolerances? If it looks right it's close enough...:-)

Michael Koblic,
Campbell River, BC

On Thu, 16 Dec 2010 05:26:26 -0800 (PST), Jim Wilkins
wrote:

On Dec 15, 11:38*pm, wrote:
...
Following the principles of the soft jaws and the step collet I
thought of attaching a 5/8"+ thick aluminum plate to one of my
faceplates, turn it true and face it. Then turn a recess in the face
of this plate with the ID=OD of my work piece (well, a slip fit).
Clean the inside of the recess as well as the work piece and attach
the work piece inside this recess with double sided sticky tape. This
should allow boring ID and facing of one side of the work piece. If
all my future pieces are turned to exactly the same OD and the face
plate-aluminum plate assembly is kept intact this setup should allow
repeat work....

Michael Koblic,

You may be remembering a similar custom wooden chuck from Holtzapfel.
There or somewhere I saw a variation with the outer lip slit and
undercut so a large sliding steel ring (hose clamp?) would wedge it
closed on the disk. I think he suggested a mix of pitch and wax,
available now as cross-country ski wax, to further hold the disk. I
use hot melt glue for such tasks, melted with a hot air gun or hair
dryer. So far it's held as long as the work doesn't become too hot to
touch.

Holztapfel would be the original reference. There have been at least a
dozen suggestions elsewhere for variations of the same: Many use wood
(MDF seemed particularly popular) and hold the piece variously with
wax, pitch, shellac, hot glue, double-sided sticky tape and superglue.

I have a problem with using wood: The sacrificial plate would have to
be turned on the metal lathe to get the centering just right and that
would create an unholy mess. I thought aluminum would be a reasonable
compromise. My concern with pitch, wax, hot glue etc. was that you
have to get a definite layer of the adhesive between the piece and the
plate. Making sure that it lies flat against it would be, I imagine,
difficult to achieve. How did you manage it yourself? I have tried the
double sided sticky tape in other applications and thought it an
advancement on an old idea.

My large thin disks are gear or pulley blanks which can tolerate extra
mounting holes, and I have 5C pot collets to hold them.
http://media.photobucket.com/image/p...chine/pot2.jpg

This (see?) second-hand pot collet had been pretty much used up for
custom jobs, so I refurbished it by boring the inside smooth and
turning a matching plug on the side of a thick aluminum disk. After
tapping the aluminum and screwing it to the collet I sawed it into
sections. The steps I've cut are as shallow as 0.020", to hold thin
spacer washers.

OK this would be what others called a "step collet"?

Some of the older pot collets have a solid shank and a tapered closer
ring at the OD like the wooden chucks. I'm trying to think of a way to
mount an inside-tapered ring on a face plate such that it would force
pie jaw plates inwards as you tightened them against the faceplate.
Perhaps a large tapered pipe thead like a drain pipe cleanout plug
would hold square while closing the jaws.

That is getting too clever for me. Which is where the double-sided
sticky tape comes it :-)

There seems no doubt that if one did a lot of this the pie jaw
solution is the best one. A better 4-jaw chuck follows some way behind
as, if I am correct in diagnosing the problem as flexing of the part,
it would not really solve the problem. I am told that my lather is too
small for 5C collets but looking at this it may not be strictly true:

http://www.youtube.com/watch?v=zHDa707aEBQ

Either way, not much change from $500 when all is said and done, pie
jaws or 5C collets.

Fortunately the issue is neither critical nor time-sensitive.

Michael Koblic,
Campbell River, BC

wrote in message
...
snip-
I don't think I can add much to the OP.
The end result should look something like this:

http://www.flickr.com/photos/27683124@N07/5242609640/

Tolerances? If it looks right it's close enough...:-)

That part screams for soft jaws. Trust me!

Harold

On Thu, 16 Dec 2010 22:16:46 -0800, wrote:

I have a problem with using wood: The sacrificial plate would have to
be turned on the metal lathe to get the centering just right and that
would create an unholy mess.

Nah! If you don't have a dust collector, think Shop Vac, Mikey. Catch
it at the tool and there is no mess. Dust collectors are quite quiet,
while most shopvacs are noisyassed beasts. Your choice.


--
Small opportunities are often the beginning of great enterprises.
-- Demosthenes

Larry Jaques fired this volley in
:

Nah! If you don't have a dust collector, think Shop Vac, Mikey. Catch
it at the tool and there is no mess.

Larry, you'd have to do a quite workman-like job of collecting that dust.
Wood flour is the bane of metal machinery. It's also damned hard to
collect all of it with a vacuum cleaner -- there's just not enough volume
OR large enough cross-section of moving air to catch all the fugative
dust. That job really requires a high-volume dust collector.

Nahh... I don't like wood on the metal lathe, either. Were it me, I'd be
backing that thing up with a sheet of type I PVC -- something I can glue
to effectively, then later dissolve or de-bond.

LLoyd

On Dec 17, 1:16*am, wrote:
On Thu, 16 Dec 2010 05:26:26 -0800 (PST), Jim Wilkins
...
Holztapfel would be the original reference. There have been at least a
dozen suggestions elsewhere for variations of the same: Many use wood
(MDF seemed particularly popular) and hold the piece variously with
wax, pitch, shellac, hot glue, double-sided sticky tape and superglue.

I have a problem with using wood: The sacrificial plate would have to
be turned on the metal lathe to get the centering just right and that
would create an unholy mess.

I turn wood, plastic and rubber on my metal lathe. It helps to pick a
depth of cut that makes reasonable-sized chips, not huge ones or dust.

Wood chips vacuum up easily. They might cling to grease but not way
oil, which they absorb. Just yesterday I adapted a 3/4" flex tube to a
vacuum cleaner to reach into narrow spaces, in this case the bell
housing of my truck which chipmunks had filled with acorns after I
screened off the air cleaner inlet.

At several jobs they had added a short garden hose etc to the shop vac
to clean out tee slots and other recesses on machinery. The narrow
radiator attachment is too long and awkward and the others are
ineffective.

I thought aluminum would be a reasonable
compromise. My concern with pitch, wax, hot glue etc. was that you
have to get a definite layer of the adhesive between the piece and the
plate. Making sure that it lies flat against it would be, I imagine,
difficult to achieve. How did you manage it yourself?

Heat the work hot enough to melt the glue and press it firmly in place
with the tailstock center.
http://www.vintageprojects.com/machi...pipecenter.pdf
Then check for runout.

My large thin disks are gear or pulley blanks which can tolerate extra
mounting holes, and I have 5C pot collets to hold them.
http://media.photobucket.com/image/p...idaho/Machine/...
This (see?) second-hand pot collet ...

OK this would be what others called a "step collet"?

If they have steps. Photos load very slowly on dialup so I take the
first one that's close.

The collets I have were originally flat-faced disks, like the
Microcentric pie jaws in my photo. They were machined to hold specific
parts, then re-used for larger ones, until they were used up.

...I'm trying to think of a way to
mount an inside-tapered ring on a face plate such that it would force
pie jaw plates inwards as you tightened them against the faceplate.
Perhaps a large tapered pipe thead like a drain pipe cleanout plug
would hold square while closing the jaws.

That is getting too clever for me. Which is where the double-sided
sticky tape comes it :-)

There seems no doubt that if one did a lot of this the pie jaw
solution is the best one.

I haven't needed to make top jaws for my 5" Bison 3-jaw, but on
examination it doesn't look too challenging as long as you true the
clamping surface in the lathe. You can remove the inner jaws to test
the fit without removing the new top jaws from the milling vise, and
shave down the backs to barely clear the chuck body afterwards. The
crosswise tenon engages before the radial slot, so you can fit each
individually. I think you could get away with a loose fit for them, as
clamping the work will take up the slack. However the Bison ones were -
very- carefully fitted and are marked with the chuck serial number and
jaw 1, 2 and 3.

This chuck is fully 6" from the end of the mounting plate to the jaw
tips, which eats up a lot of work space and could be too much overhang
for a lathe with a thinner spindle.

A better 4-jaw chuck follows some way behind
as, if I am correct in diagnosing the problem as flexing of the part,
it would not really solve the problem. I am told that my lather is too
small for 5C collets but looking at this it may not be strictly true:

http://www.youtube.com/watch?v=zHDa707aEBQ

For me 1 minute of video takes 10 minutes to load.

Either way, not much change from $500 when all is said and done, pie
jaws or 5C collets.

Michael Koblic,
Campbell River, BC

I suggested Holtzapffel to you because it's full of ways to save that
$500, and he was also chucking ornamental objects that scratch easily,
which is really the reason for wood jaws.

I think the best way to get 5C collets is to buy a lathe made to hold
them in the spindle. They are more useful for high precision like
optical or hydraulic parts than for general use. I still do a lot
between centers or on a faceplate.

jsw

On Fri, 17 Dec 2010 07:54:17 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
:

Nah! If you don't have a dust collector, think Shop Vac, Mikey. Catch
it at the tool and there is no mess.

Larry, you'd have to do a quite workman-like job of collecting that dust.
Wood flour is the bane of metal machinery. It's also damned hard to
collect all of it with a vacuum cleaner -- there's just not enough volume
OR large enough cross-section of moving air to catch all the fugative
dust. That job really requires a high-volume dust collector.

Wood flour is created by -dull- tools. Keep 'em sharp and you get
shavings which are much larger in crossection.

--
Small opportunities are often the beginning of great enterprises.
-- Demosthenes

Larry Jaques fired this volley in
:

Wood flour is created by -dull- tools.

Fire and smoke and burned cut lines are created by dull tools. Wood dust
can be caused by an exquisitely sharp tool taking fine cuts. Wood flexes
a bit under cutting pressure. When it recovers from the first deep cut of
the tool, it gets lightly shaved by subsequent passes. Even a properly-
adjusted (and sharp, and HONED) surface plane produces a combination of
nice curls and fine dust; not _much_ dust, but some.

Cutting lightly against the backing would have that effect. So, are you
recommending he cut hard and full against the backing piece on every
pass? What about when he stops the feed. Does that last tenth the tool
takes off after it stops moving count as a "fine feed", or no?

I'm a so-so home shop machinist, but a _very_ competent furniture maker.
There's not much about the machinability of wood (from the common to
poisonous exotics) you could teach me. And I'll hold to my first -- wood
particles of quite nearly any size are persona non grata around
metalworking equipment. Even _shavings_ will absorb oil.

LLoyd

On Fri, 17 Dec 2010 10:22:31 -0600, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Larry Jaques fired this volley in
:

Wood flour is created by -dull- tools.

Fire and smoke and burned cut lines are created by dull tools. Wood dust
can be caused by an exquisitely sharp tool taking fine cuts. Wood flexes
a bit under cutting pressure. When it recovers from the first deep cut of
the tool, it gets lightly shaved by subsequent passes. Even a properly-
adjusted (and sharp, and HONED) surface plane produces a combination of
nice curls and fine dust; not _much_ dust, but some.

OK, 99.6% shavings, 0.4% flour. But fine dust is most easily picked
up by the dust collector (if you have HEPA sub-micron bags.)


Cutting lightly against the backing would have that effect. So, are you
recommending he cut hard and full against the backing piece on every
pass? What about when he stops the feed. Does that last tenth the tool
takes off after it stops moving count as a "fine feed", or no?

Oui.


I'm a so-so home shop machinist, but a _very_ competent furniture maker.
There's not much about the machinability of wood (from the common to
poisonous exotics) you could teach me. And I'll hold to my first -- wood
particles of quite nearly any size are persona non grata around
metalworking equipment. Even _shavings_ will absorb oil.

OK, I catch your drift, but on a limited basis, a bit of wooddorking
on a metalworking machine won't do it any harm. Just wipe and reoil
the ways afterward if you need to. How much harm does wood do to the
ways, anyway? It's MUCH softer than iron/steel. Bamboo (seldom
machined) has lots of tough silicates, but most wood is primarily a
soft cellulose.

--
The art of life lies in a constant readjustment to our surroundings.
-- Okakura Kakuzo

On Dec 17, 11:44*am, Larry Jaques
wrote:
...
OK, I catch your drift, but on a limited basis, a bit of wooddorking
on a metalworking machine won't do it any harm. Just wipe and reoil
the ways afterward if you need to. How much harm does wood do to the
ways, anyway? *...

Maybe the results depend on the species of wood. I use red oak and see
hardly any dust, either turning or planing. And my lathe has felt way
wipes.

How did pattern makers manage wood on metal lathes?

jsw

On Fri, 17 Dec 2010 06:47:53 -0800 (PST), Jim Wilkins
wrote:

[...]

This chuck is fully 6" from the end of the mounting plate to the jaw
tips, which eats up a lot of work space and could be too much overhang
for a lathe with a thinner spindle.

That is has been my concern all along. I shall check with other 9x20
owners.

[...]

Michael Koblic,
Campbell River, BC

Another option might be to fabricate some better/new jaws for your existing
"basic" 4-jaw chuck that comes with 9x20 lathes, or to modify the present
jaws.

Pie jaw descriptions (and the pot collets) that have been discussed have
essentially been nearly full circle support for the workpiece.

You may be able to fabricate some jaws that have more support/grip surface
area (or modify the existing jaws) so that the perimeter workpiece contact
area is significantly much greater, but not an entire full circle.

I'm not sure about the jaw treatment on the "basic" chucks, but I would
expect them to be fairly soft mild steel, but possibly case hardened,
although not likely to be anywhere near as hard as typical/conventional
precision chuck jaws.

If the jaws are soft enough to easily drill and tap, fabricating a bolt-on
solution could result in a fully customizable workholding fixture.

As for penetrating a case hardening, if it exists, several methods should
allow you to anneal a couple of spots for fasteners.. spot annealing heat
generated with a dowel in a drillpress, torch heat, colbalt/HSS or carbide
drill etc.

I believe that keeping the workpieces near the spindle nose bearing will
minimize chatter problems.

--
WB
..........


wrote in message
...
On Fri, 17 Dec 2010 06:47:53 -0800 (PST), Jim Wilkins
wrote:

[...]

This chuck is fully 6" from the end of the mounting plate to the jaw
tips, which eats up a lot of work space and could be too much overhang
for a lathe with a thinner spindle.

That is has been my concern all along. I shall check with other 9x20
owners.

[...]

Michael Koblic,
Campbell River, BC

On Dec 18, 12:58*am, "Wild_Bill" wrote:
Another option might be to fabricate some better/new jaws for your existing
"basic" 4-jaw chuck that comes with 9x20 lathes, or to modify the present
jaws.
...

I don't know exactly what your lathe is like with and can only
extrapolate from industrial lathe methods that may not be appropriate
on a simpler hobby lathe.

Considering the problems with small pie chuck jaws I still think my
earlier suggestion of a wooden block on a faceplate may be worth the
nuisance it brings.That was to glue the disk blank to the wood and
screw on temporary clamps to either the OD or ID while turning the
other. The glue mostly has to hold the disk in place while you move
the clamps.

You could make dog clamps to keep it centered while facing. These are
blocks that attach to the faceplate, with screws at a right angle to
press in radially on the work. The other clamps are woodscrews with
steel and faucet washers.

Standard practice for turning wood bowls is to glue the blank to a
wood faceplate overlay with one layer of newspaper in the glue joint.
It holds very well and then breaks cleanly when you tap a chisel into
the joint.

jsw

He certainly has options available with his existing tooling/accessories.

Double-sided tape (not the thick stuff, with foam in the center) is somewhat
commonly available in 1/2" and 2" widths. I've seen 1/2" DST available in
stores that stock winterizing/weatherproofing products as a method of
applying plastic film to window openings, and the 2" width is often
available as a product for working with carpeting.

Enco and various other suppliers generally have DST in larger length rolls,
and made by 3M.
The DST method of securing thin workpieces should be adequate (it's a fairly
common shop practice) as long as the workpieces don't get too hot, as the
adhesive grip will weaken at elevated temperatures.

As Michael has mentioned that he has (I think) 2 faceplates available, each
of them could be adapted for sundial plate machining, if they're not
frequently used for other purposes.

I think we've been discussing the generic 9x20 lathe in this instance. My
experience with owning one of these light duty lathes, is that it doesn't
take much to induce chatter with these models.
That's why I've been making suggestions for faceplate or the supplied 4-jaw
chuck for turning/facing the sundial plates, as the working diameters are
relatively large for these lathes.
These existing accessories will keep the workpieces close to the spindle
nose bearing, which will likely minimize the risk of chatter, whereas I
believe the addition of a new chuck will likely increase the likelyhood of
chatter due to the extended overhang distance from the spindle nose bearing.

Machining these sundial workpieces seems as though it would be very much
like working a bowl on a wood lathe, since the workpiece is free-hanging
from the spindle/workholding accessory.

Protecting the precision lathe parts from wood debris isn't very troublesome
by just using some disposable material such as newspaper or aluminum foil
and possibly some masking tape. Paper products covering the lathe bed
wouldn't be especially suitable if hot metal chips are present.

--
WB
..........


"Jim Wilkins" wrote in message
...
On Dec 18, 12:58 am, "Wild_Bill" wrote:
Another option might be to fabricate some better/new jaws for your
existing
"basic" 4-jaw chuck that comes with 9x20 lathes, or to modify the present
jaws.
...

I don't know exactly what your lathe is like with and can only
extrapolate from industrial lathe methods that may not be appropriate
on a simpler hobby lathe.

Considering the problems with small pie chuck jaws I still think my
earlier suggestion of a wooden block on a faceplate may be worth the
nuisance it brings.That was to glue the disk blank to the wood and
screw on temporary clamps to either the OD or ID while turning the
other. The glue mostly has to hold the disk in place while you move
the clamps.

You could make dog clamps to keep it centered while facing. These are
blocks that attach to the faceplate, with screws at a right angle to
press in radially on the work. The other clamps are woodscrews with
steel and faucet washers.

Standard practice for turning wood bowls is to glue the blank to a
wood faceplate overlay with one layer of newspaper in the glue joint.
It holds very well and then breaks cleanly when you tap a chisel into
the joint.

jsw

On Sun, 19 Dec 2010 13:56:29 -0500, "Wild_Bill"
wrote:

He certainly has options available with his existing tooling/accessories.

Double-sided tape (not the thick stuff, with foam in the center) is somewhat
commonly available in 1/2" and 2" widths. I've seen 1/2" DST available in
stores that stock winterizing/weatherproofing products as a method of
applying plastic film to window openings, and the 2" width is often
available as a product for working with carpeting.

Enco and various other suppliers generally have DST in larger length rolls,
and made by 3M.
The DST method of securing thin workpieces should be adequate (it's a fairly
common shop practice) as long as the workpieces don't get too hot, as the
adhesive grip will weaken at elevated temperatures.

As Michael has mentioned that he has (I think) 2 faceplates available, each
of them could be adapted for sundial plate machining, if they're not
frequently used for other purposes.

Right now if (and it is a big if) I continue with this line there are
three sizes I make. The miniatures are no problem, they get done on
the Taig and bored in the 3-jaw on the 9x20. The 4.5" and 5.5" could
be standardized and each face plate dedicated to one size. If I can
make it work it would be far and away the cheapest solution even if I
had to buy more face plates.

I think we've been discussing the generic 9x20 lathe in this instance. My
experience with owning one of these light duty lathes, is that it doesn't
take much to induce chatter with these models.
That's why I've been making suggestions for faceplate or the supplied 4-jaw
chuck for turning/facing the sundial plates, as the working diameters are
relatively large for these lathes.
These existing accessories will keep the workpieces close to the spindle
nose bearing, which will likely minimize the risk of chatter, whereas I
believe the addition of a new chuck will likely increase the likelyhood of
chatter due to the extended overhang distance from the spindle nose bearing.

That is a consideration. I did check with other 9x20 users and some
seem to like 5" chucks better than 4" chucks, however, this may be
related to the quality of the manufacture. None reported any problems.
One even run a 6" 3-jaw.

Either way the cost of a Polish 5" 3-jaw, back plate and pie jaws is
$500 give or take. Not something to undertake lightly.

An interesting point: I see that many manufacturers make the chucks
with plain backs but also with threaded backs. I can see the need to
turn the back plate to fit one's particular lathe to make the chuck
run true but I am not sure how this works with a chuck that has
already been threaded unless it is a "Set-through" chuck which these
are not.

Machining these sundial workpieces seems as though it would be very much
like working a bowl on a wood lathe, since the workpiece is free-hanging
from the spindle/workholding accessory.

Protecting the precision lathe parts from wood debris isn't very troublesome
by just using some disposable material such as newspaper or aluminum foil
and possibly some masking tape. Paper products covering the lathe bed
wouldn't be especially suitable if hot metal chips are present.

I use cling film when working with abrasives. One would hope that wood
chips would not be *that* hot...

I shall be looking at this in the New year. Right now it's the turn of
other manufacturing processes.

Michael Koblic,
Campbell River, BC

While checking about what other 9x20 lathe users who have implemented larger
sizes of (heavier) conventional chucks, you might inquire if they are making
chatter-free facing cuts on fairly large diameter workpieces, without the
use of the tailstock for support.

An additional factor could be if the other users have variable speed motors,
which can be a significant factor in chatter-free finishes.

I haven't priced the cheap generic lathe chucks recently, but the last cheap
chuck I bought was a 6" 4-jaw for about $55 +s/h from JTS Machine(?) in
Mentor/Cleveland Ohio.
I bought that chuck for a different machine that had a 8" 4-jaw, which was
much larger than I normally needed.

I don't doubt that the 9x20 could handle running a heavier 5" or 6" chuck,
however, I doubt that with the additional distance from the spindle nose
bearing (2-3" more overhang) it would be trouble-free to face moderately
large diameter workpieces without chatter.

A variable speed drive (AC or DC) would give the operator a better chance of
tuning the cutting speed to avoid chatter, but otherwise I would be
expecting to have problems attaining smooth finishes.
I expect that many, more experienced (than I) lathe operators would adjust
the angles on the cutting tool and have everything dialed in rather quickly.

I guess the YMMV comment applies here.

What I was thinking is "that'll be the day".. when I buy a $500 chuck to put
on a ($600 when bought) Chinese lathe.
The chucks don't necessarily assure better quality parts.. they're mainly
just a convenience, easier than working with only a faceplate, dog and
centers, and a mandrel for items like the sundial faces.

I think it mat have been Harold that commented that just about any 3-jaw
chuck would be suitable for using pie jaws with.. since the workholding
surfaces are cut in place, they're already concentric with and perpendicular
to, the spindle's centerline (even if the chuck itself had previous accuracy
problems).

The best to you and yours this season, Michael

--
WB
..........


wrote in message
...

Right now if (and it is a big if) I continue with this line there are
three sizes I make. The miniatures are no problem, they get done on
the Taig and bored in the 3-jaw on the 9x20. The 4.5" and 5.5" could
be standardized and each face plate dedicated to one size. If I can
make it work it would be far and away the cheapest solution even if I
had to buy more face plates.


That is a consideration. I did check with other 9x20 users and some
seem to like 5" chucks better than 4" chucks, however, this may be
related to the quality of the manufacture. None reported any problems.
One even run a 6" 3-jaw.

Either way the cost of a Polish 5" 3-jaw, back plate and pie jaws is
$500 give or take. Not something to undertake lightly.

An interesting point: I see that many manufacturers make the chucks
with plain backs but also with threaded backs. I can see the need to
turn the back plate to fit one's particular lathe to make the chuck
run true but I am not sure how this works with a chuck that has
already been threaded unless it is a "Set-through" chuck which these
are not.

Machining these sundial workpieces seems as though it would be very much
like working a bowl on a wood lathe, since the workpiece is free-hanging
from the spindle/workholding accessory.

Protecting the precision lathe parts from wood debris isn't very
troublesome
by just using some disposable material such as newspaper or aluminum foil
and possibly some masking tape. Paper products covering the lathe bed
wouldn't be especially suitable if hot metal chips are present.

I use cling film when working with abrasives. One would hope that wood
chips would not be *that* hot...

I shall be looking at this in the New year. Right now it's the turn of
other manufacturing processes.

Michael Koblic,
Campbell River, BC

"Wild_Bill" wrote in message
...
snip--

I think it mat have been Harold that commented that just about any 3-jaw
chuck would be suitable for using pie jaws with.. since the workholding
surfaces are cut in place, they're already concentric with and
perpendicular to, the spindle's centerline (even if the chuck itself had
previous accuracy problems).

That's correct! (Assuming the chuck has master jaws). The precision is
established by technique, it's not a function of the quality or condition of
the chuck. Even a lousy three jaw with sprung slides is capable of decent
work, assuming you follow "the rules" when preparing soft jaws. In the
hands of a fool, they can, and will, disappoint----but when applied
properly, they can be salvation when all other attempts fail.

Harold

On Dec 20, 12:15*am, "Harold & Susan Vordos" wrote:
...Even a lousy three jaw with sprung slides is capable of decent
work, assuming you follow "the rules" when preparing soft jaws. * In the
hands of a fool, they can, and will, disappoint----but when applied
properly, they can be salvation when all other attempts fail.

Harold

How do you preload the jaws to turn the clamping surfaces when they
will expand outwards? I don't have an expensive ring set and was
wondering about wrapping a strap around the jaws.

jsw

On Sun, 19 Dec 2010 22:41:32 -0500, "Wild_Bill"
wrote:

While checking about what other 9x20 lathe users who have implemented larger
sizes of (heavier) conventional chucks, you might inquire if they are making
chatter-free facing cuts on fairly large diameter workpieces, without the
use of the tailstock for support.

If you ask a male golfer how far he hits his driver the answer is
never less than 240 yards.

If you ask a fellow 9x20-er if his pieces chatter the answer is never.
Under any circumstances!

When I had issues with the finish of my disks I was sent photos of
similar items to show me "how to do it". The finish was worse than
mine :-)

An additional factor could be if the other users have variable speed motors,
which can be a significant factor in chatter-free finishes.

Indeed. Many do have them.

I haven't priced the cheap generic lathe chucks recently, but the last cheap
chuck I bought was a 6" 4-jaw for about $55 +s/h from JTS Machine(?) in
Mentor/Cleveland Ohio.
I bought that chuck for a different machine that had a 8" 4-jaw, which was
much larger than I normally needed.

But then a 4-jaw independent would defeat the purpose of the pie jaws.

I don't doubt that the 9x20 could handle running a heavier 5" or 6" chuck,
however, I doubt that with the additional distance from the spindle nose
bearing (2-3" more overhang) it would be trouble-free to face moderately
large diameter workpieces without chatter.

A variable speed drive (AC or DC) would give the operator a better chance of
tuning the cutting speed to avoid chatter, but otherwise I would be
expecting to have problems attaining smooth finishes.
I expect that many, more experienced (than I) lathe operators would adjust
the angles on the cutting tool and have everything dialed in rather quickly.

I guess the YMMV comment applies here.

I have learned some of that, not being able to go lower than 150 rpm.
In fact the differences from tool to tool can be striking. I am still
struggling with consistency.

Oddly enough the finish matters less on these pieces: Some get a brass
face anyway which covers a multitude of sins underneath, others get
sanded anyway as I found that unless the face is absolutely smooth,
the transfer of patterns is only partially successful.

What I was thinking is "that'll be the day".. when I buy a $500 chuck to put
on a ($600 when bought) Chinese lathe.
The chucks don't necessarily assure better quality parts.. they're mainly
just a convenience, easier than working with only a faceplate, dog and
centers, and a mandrel for items like the sundial faces.

I think it mat have been Harold that commented that just about any 3-jaw
chuck would be suitable for using pie jaws with.. since the workholding
surfaces are cut in place, they're already concentric with and perpendicular
to, the spindle's centerline (even if the chuck itself had previous accuracy
problems).

As Harold is about to say: "Only if they have two-piece jaws".

The best to you and yours this season, Michael

And yourself.

Michael Koblic,
Campbell River, BC

On Mon, 20 Dec 2010 05:15:30 GMT, "Harold & Susan Vordos"
wrote:


"Wild_Bill" wrote in message
...
snip--

I think it mat have been Harold that commented that just about any 3-jaw
chuck would be suitable for using pie jaws with.. since the workholding
surfaces are cut in place, they're already concentric with and
perpendicular to, the spindle's centerline (even if the chuck itself had
previous accuracy problems).

That's correct! (Assuming the chuck has master jaws). The precision is
established by technique, it's not a function of the quality or condition of
the chuck. Even a lousy three jaw with sprung slides is capable of decent
work, assuming you follow "the rules" when preparing soft jaws. In the
hands of a fool, they can, and will, disappoint----but when applied
properly, they can be salvation when all other attempts fail.

To be fair the guys who preferred their 5" chucks liked them better
for general work, pie jaws were not discussed. Surely there must be
some difference between the chuck that is thrown in with the machine
and something you spend $$$s on?

Michael Koblic,
Campbell River, BC

On Mon, 20 Dec 2010 05:27:49 -0800 (PST), Jim Wilkins
wrote:

On Dec 20, 12:15*am, "Harold & Susan Vordos" wrote:
...Even a lousy three jaw with sprung slides is capable of decent
work, assuming you follow "the rules" when preparing soft jaws. * In the
hands of a fool, they can, and will, disappoint----but when applied
properly, they can be salvation when all other attempts fail.

Harold

How do you preload the jaws to turn the clamping surfaces when they
will expand outwards? I don't have an expensive ring set and was
wondering about wrapping a strap around the jaws.


FWIW, I put a cable tie around the outside of my Taig aluminum jaws
and then turned a couple of steps on them.

Michael Koblic,
Campbell River, BC

On Dec 20, 7:21*pm, wrote:
On Sun, 19 Dec 2010 22:41:32 -0500, "Wild_Bill"

If you ask a fellow 9x20-er if his pieces chatter the answer is never.
Under any circumstances!

My South Bend certainly chatters if the surface speed is too high.
Then I slap it into back gear and watch the work slowly revolve like a
cement mixer.

But then a 4-jaw independent would defeat the purpose of the pie jaws.

Maybe not. You could turn the outside smooth and indicate on it. When
I need to temporarily remove the work I loosen the jaws on either side
of the label and then tighten only them to put it back. Usually a cut
less than 0.005" deep removes metal all the way around.

[cut & paste]
To be fair the guys who preferred their 5" chucks liked them better
for general work, pie jaws were not discussed. Surely there must be
some difference between the chuck that is thrown in with the machine
and something you spend $$$s on?
What I was thinking is "that'll be the day".. when I buy a $500 chuck to put
on a ($600 when bought) Chinese lathe.

I really do like that $500 Bison Set-Tru, though. You could think of
one as the first installment on a larger lathe.

jsw

On 2010-12-20, wrote:

[ ... ]

That is a consideration. I did check with other 9x20 users and some
seem to like 5" chucks better than 4" chucks, however, this may be
related to the quality of the manufacture. None reported any problems.
One even run a 6" 3-jaw.

The main thing to worry about when using a 3-jaw chuck larger
than approximately half the swing of the lathe is that you have to be
*very* careful to always turn the chuck by hand through a full turn
after griping something larger. The back end of the jaws can stick out
far enough to hit the bed ways -- damaging both the jaws and the ways.

Either way the cost of a Polish 5" 3-jaw, back plate and pie jaws is
$500 give or take. Not something to undertake lightly.

Depends on the size of your lathe. With some sizes, that is
beyond dirt cheap. :-)

An interesting point: I see that many manufacturers make the chucks
with plain backs but also with threaded backs. I can see the need to
turn the back plate to fit one's particular lathe to make the chuck
run true but I am not sure how this works with a chuck that has
already been threaded unless it is a "Set-through" chuck which these
are not.

Wrong term there. The usual spelling of one maker's name for
the chuck is "set-tru" which is short for "set true" (*not* through).
There is someone else here who frequently uses that wrong term -- though
usually spelled "adjust-thru" IIRC.

However, if the chuck has already been threaded, it may be that
the jaws have been ground true while mounted in the chuck. The thing
that turning your own backplate does is to compensate for errors in the
spindle of *your* machine -- and make it less accurate on somebody
else's machine. A friend had a 10" lathe with two adjust-tru (another
manufacturer's trademarked name for the same feature) chucks, which ran
fine -- but every time I tried to adapt something else to it it had lots
of runout. It turns out that somewhen in its past, someone had
seriously crashed the machine, and the threaded part of the spindle nose
was bent -- not enough to see easily, but enough to introduce
progressively worse runout as you moved the indicator away from the
headstock.

We eventually got a replacement spindle via eBay.

But -- a pre-threaded chuck is a convenient think -- *if* you
can trust your spindle nose to be true.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
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 ---

"Jim Wilkins" wrote in message
...
On Dec 20, 12:15 am, "Harold & Susan Vordos" wrote:
...Even a lousy three jaw with sprung slides is capable of decent
work, assuming you follow "the rules" when preparing soft jaws. In the
hands of a fool, they can, and will, disappoint----but when applied
properly, they can be salvation when all other attempts fail.

Harold

How do you preload the jaws to turn the clamping surfaces when they
will expand outwards? I don't have an expensive ring set and was
wondering about wrapping a strap around the jaws.

jsw

In all my years, I ran only one job that required that setup. *Really!*
:-)
If you took a look at the link I provided, think about the "spider" I talked
about. You can make a ring with tapped holes located precisely @ 120
degrees so you can load the jaws upon expansion. As long as you're in front
of the scroll, you'll achieve success of sorts, but the closer you load the
jaws to the location where the part will ride, the better.

With tapped holes and some all thread, you should be able to adjust jaws to
any position, which is the purpose of the spider.

As in all cases, be certain you use the same socket when tightening the
chuck---it makes a huge difference in how the chuck responds, especially if
it's worn.

The strap would work, assuming you can get it on at the desired diameter.
A ring with tapped holes would be better.

Harold

wrote in message
...
On Mon, 20 Dec 2010 05:15:30 GMT, "Harold & Susan Vordos"
wrote:


"Wild_Bill" wrote in message
...
snip--

I think it mat have been Harold that commented that just about any 3-jaw
chuck would be suitable for using pie jaws with.. since the workholding
surfaces are cut in place, they're already concentric with and
perpendicular to, the spindle's centerline (even if the chuck itself had
previous accuracy problems).

That's correct! (Assuming the chuck has master jaws). The precision is
established by technique, it's not a function of the quality or condition
of
the chuck. Even a lousy three jaw with sprung slides is capable of decent
work, assuming you follow "the rules" when preparing soft jaws. In the
hands of a fool, they can, and will, disappoint----but when applied
properly, they can be salvation when all other attempts fail.

To be fair the guys who preferred their 5" chucks liked them better
for general work, pie jaws were not discussed. Surely there must be
some difference between the chuck that is thrown in with the machine
and something you spend $$$s on?

Michael Koblic,
Campbell River, BC

No doubt, but you can wring some decent precision from a less than perfect
chuck by proper application. That's the point.

Harold

On 21 Dec 2010 05:19:41 GMT, "DoN. Nichols"
wrote:

On 2010-12-20, wrote:

[ ... ]

That is a consideration. I did check with other 9x20 users and some
seem to like 5" chucks better than 4" chucks, however, this may be
related to the quality of the manufacture. None reported any problems.
One even run a 6" 3-jaw.

The main thing to worry about when using a 3-jaw chuck larger
than approximately half the swing of the lathe is that you have to be
*very* careful to always turn the chuck by hand through a full turn
after griping something larger. The back end of the jaws can stick out
far enough to hit the bed ways -- damaging both the jaws and the ways.

I thought there was an issue with the bearings and the size of the
spindle. Also the biggies take longer to stop. The chatter issue
should be alleviated by the soft pie jaws which would be the point of
getting a new chuck in the first place.

Either way the cost of a Polish 5" 3-jaw, back plate and pie jaws is
$500 give or take. Not something to undertake lightly.

Depends on the size of your lathe. With some sizes, that is
beyond dirt cheap. :-)

No. Depends on the size of your bank account.

An interesting point: I see that many manufacturers make the chucks
with plain backs but also with threaded backs. I can see the need to
turn the back plate to fit one's particular lathe to make the chuck
run true but I am not sure how this works with a chuck that has
already been threaded unless it is a "Set-through" chuck which these
are not.

Wrong term there. The usual spelling of one maker's name for
the chuck is "set-tru" which is short for "set true" (*not* through).
There is someone else here who frequently uses that wrong term -- though
usually spelled "adjust-thru" IIRC.

That is tru.

However, if the chuck has already been threaded, it may be that
the jaws have been ground true while mounted in the chuck. The thing
that turning your own backplate does is to compensate for errors in the
spindle of *your* machine -- and make it less accurate on somebody
else's machine. A friend had a 10" lathe with two adjust-tru (another
manufacturer's trademarked name for the same feature) chucks, which ran
fine -- but every time I tried to adapt something else to it it had lots
of runout. It turns out that somewhen in its past, someone had
seriously crashed the machine, and the threaded part of the spindle nose
was bent -- not enough to see easily, but enough to introduce
progressively worse runout as you moved the indicator away from the
headstock.

We eventually got a replacement spindle via eBay.

But -- a pre-threaded chuck is a convenient think -- *if* you
can trust your spindle nose to be true.

Also much more expensive. OTOH others tell me that they had problems
with some of the back plates.

Michael Koblic,
Campbell River, BC

On Mon, 20 Dec 2010 17:01:31 -0800 (PST), Jim Wilkins
wrote:

On Dec 20, 7:21*pm, wrote:
On Sun, 19 Dec 2010 22:41:32 -0500, "Wild_Bill"

If you ask a fellow 9x20-er if his pieces chatter the answer is never.
Under any circumstances!

My South Bend certainly chatters if the surface speed is too high.
Then I slap it into back gear and watch the work slowly revolve like a
cement mixer.

I thought that's what the big handle was for. Admittedly coordinating
the left hand cranking the spindle and the right hand turning the
cross-feed is a bit tricky.

But then a 4-jaw independent would defeat the purpose of the pie jaws.

Maybe not. You could turn the outside smooth and indicate on it. When
I need to temporarily remove the work I loosen the jaws on either side
of the label and then tighten only them to put it back. Usually a cut
less than 0.005" deep removes metal all the way around.

If one is going to go through the hassle of getting a new chuck it may
as well be one that is the least hassle in use.

[cut & paste]
To be fair the guys who preferred their 5" chucks liked them better
for general work, pie jaws were not discussed. Surely there must be
some difference between the chuck that is thrown in with the machine
and something you spend $$$s on?
What I was thinking is "that'll be the day".. when I buy a $500 chuck to put
on a ($600 when bought) Chinese lathe.

I really do like that $500 Bison Set-Tru, though. You could think of
one as the first installment on a larger lathe.

And the larger lathe the first installment on a bigger house...

Michael Koblic,
Campbell River, BC

On Dec 21, 11:37*pm, wrote:
On Mon, 20 Dec 2010 17:01:31 -0800 (PST), Jim Wilkins

wrote:
On Dec 20, 7:21*pm, wrote:
On Sun, 19 Dec 2010 22:41:32 -0500, "Wild_Bill"

If you ask a fellow 9x20-er if his pieces chatter the answer is never.
Under any circumstances!

My South Bend certainly chatters if the surface speed is too high.
Then I slap it into back gear and watch the work slowly revolve like a
cement mixer.

I thought that's what the big handle was for. Admittedly coordinating
the left hand cranking the spindle and the right hand turning the
cross-feed is a bit tricky.

But then a 4-jaw independent would defeat the purpose of the pie jaws.

Maybe not. You could turn the outside smooth and indicate on it. When
I need to temporarily remove the work I loosen the jaws on either side
of the label and then tighten only them to put it back. Usually a cut
less than 0.005" deep removes metal all the way around.

If one is going to go through the hassle of getting a new chuck it may
as well be one that is the least hassle in use.

[cut & paste]
To be fair the guys who preferred their 5" chucks liked them better
for general work, pie jaws were not discussed. Surely there must be
some difference between the chuck that is thrown in with the machine
and something you spend $$$s on?
What I was thinking is "that'll be the day".. when I buy a $500 chuck to put
on a ($600 when bought) Chinese lathe.

I really do like that $500 Bison Set-Tru, though. You could think of
one as the first installment on a larger lathe.

And the larger lathe the first installment on a bigger house...

Michael Koblic,
Campbell River, BC

If you don't require the precision to make machine parts you might
consider an old worn engine lathe, now that you know how they work and
what you need. Threaded spindles and leather drive belts are fine for
a home shop lathe.

My $100 surface grinder for example is worn beyond usefulness for
precision flat grinding, but still serves well to resharpen tools.

The first small lathe I bought had ways that dipped about half a
millimeter near the chuck. Nevertheless it was good enough for the
small brass and aluminum parts I wanted to make, and could still
thread accurately enough at the tailstock end.

jsw

On 2010-12-22, wrote:
On 21 Dec 2010 05:19:41 GMT, "DoN. Nichols"
wrote:

[ ... ]

The main thing to worry about when using a 3-jaw chuck larger
than approximately half the swing of the lathe is that you have to be
*very* careful to always turn the chuck by hand through a full turn
after griping something larger. The back end of the jaws can stick out
far enough to hit the bed ways -- damaging both the jaws and the ways.

I thought there was an issue with the bearings and the size of the
spindle.

A consideration -- especially with a small diameter spindle
which is easy to bend. But that is something which either is or is not
a problem to be determined once. The jaws hitting the bed are something
to be considered every time you use the chuck.

I've got a 10" 4-jaw on my 12x24" Clausing, but only a 6-1/4"
3-jaw.

Also the biggies take longer to stop. The chatter issue
should be alleviated by the soft pie jaws which would be the point of
getting a new chuck in the first place.

The chatter might be damped by the greater mass, (and certainly
by the pie jaws), but you still have the problem of flexing of a skinny
spindle.

Craftsman has sold (in the past) two flavors of 6" lathe. The
better one is the one made by Atlas, with (IIRC) a 1"-10 spindle nose
thread, while they also had one made by Ann Arbor machine tools which
only had a 1/2"-20 spindle nose -- and those were notorious for getting
bent the first time you took a heavy cut.

Either way the cost of a Polish 5" 3-jaw, back plate and pie jaws is
$500 give or take. Not something to undertake lightly.

Depends on the size of your lathe. With some sizes, that is
beyond dirt cheap. :-)

No. Depends on the size of your bank account.

"Dirt cheap" in terms of what is available to fit your lathe.
There are lathes which have chucks 40" diameter or larger.

[ ... ]

But -- a pre-threaded chuck is a convenient thing -- *if* you
can trust your spindle nose to be true.

Also much more expensive. OTOH others tell me that they had problems
with some of the back plates.

The pre-threaded ones, or the ones which they had to machine to
fit their lathe?

My Clausing came with a 2-1/4x8 spindle nose, and I had to make
some backplates to fit (sometimes enlarging the hole in existing
backplates which had been used on 1-1/2x8 spindles or the like.
Overall, I had no problems with those. The trick for turning the bore
to clear the register was to mount the backplate backwards with a spacer
ring to hold it far enough out so I could bore the threads off at that
end.

Enjoy,
DoN.

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On 2010-12-22, wrote:
On Mon, 20 Dec 2010 17:01:31 -0800 (PST), Jim Wilkins
wrote:

On Dec 20, 7:21*pm, wrote:
On Sun, 19 Dec 2010 22:41:32 -0500, "Wild_Bill"

If you ask a fellow 9x20-er if his pieces chatter the answer is never.
Under any circumstances!

My South Bend certainly chatters if the surface speed is too high.
Then I slap it into back gear and watch the work slowly revolve like a
cement mixer.

I thought that's what the big handle was for. Admittedly coordinating
the left hand cranking the spindle and the right hand turning the
cross-feed is a bit tricky.

The crank on the spindle is for lathes which don't *have* back
gears -- or do have them, but still can't go slow enough. I think that
the 9x and 7x import lathes don't have real back gears, and thus can't
get really slow enough.

Enjoy,
DoN.

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On 23 Dec 2010 04:18:52 GMT, "DoN. Nichols"
wrote:



[ ... ]


The pre-threaded ones, or the ones which they had to machine to
fit their lathe?

My Clausing came with a 2-1/4x8 spindle nose, and I had to make
some backplates to fit (sometimes enlarging the hole in existing
backplates which had been used on 1-1/2x8 spindles or the like.
Overall, I had no problems with those. The trick for turning the bore
to clear the register was to mount the backplate backwards with a spacer
ring to hold it far enough out so I could bore the threads off at that
end.

The pre-threaded, semi-finished back plates. If I remember correctly
the threads were cut at an angle to the spindle axis. I understand
that it was correctable though.

Michael Koblic,
Campbell River, BC