I have sort of worked out the headstock which should spin things as low as
60 rpm.
I am kind of stuck with the tooling side: the carriage, crosslide etc.
One of the questions I am struggling with is the size of the tooling
appropriate for this job (turning disks up to 9" in diameter). Instinctively
I feel that a 3/16 tool is not going to cut it (sorry about the pun). But am
I right?

I have a boxful of 3/16 and 1/4" tools, toolholders with carbide inserts,
toolposts and something which I take to be a crosslide of some sort into
which all these things fit. They all look rather puny. Would they do a job
of truing up the edge of a 9"x 1/4" disk? Would they face it? Or should I
design around something more beefy? If so, how much more beefy?

--
Michael Koblic,
Campbell River, BC

Michael Koblic wrote:
I have sort of worked out the headstock which should spin things as
low as 60 rpm.
I am kind of stuck with the tooling side: the carriage, crosslide etc.
One of the questions I am struggling with is the size of the tooling
appropriate for this job (turning disks up to 9" in diameter).
Instinctively I feel that a 3/16 tool is not going to cut it (sorry
about the pun). But am I right?

I have a boxful of 3/16 and 1/4" tools, toolholders with carbide
inserts, toolposts and something which I take to be a crosslide of
some sort into which all these things fit. They all look rather puny.
Would they do a job of truing up the edge of a 9"x 1/4" disk? Would
they face it? Or should I design around something more beefy? If so,
how much more beefy?

I'm using 1/4" cutters with a lantern toolpost , they should cut anything
your lathe has the power to machine . You might want to check what the tool
bits are made of , HSS is OK , but cobalt steel is better . I'm using 5% and
8% cobalt ( M35 and M42 ?) cutters , they'll do just about everything I need
.. What they won't cut , the brazed carbides will . Start out light , low ,
and slow ... light cuts at a low feed rate and slow spindle speeds .
--
Snag
every answer
leads to another
question

"Michael Koblic" wrote in message
...
I have sort of worked out the headstock which should spin things as low as
60 rpm.
I am kind of stuck with the tooling side: the carriage, crosslide etc.
One of the questions I am struggling with is the size of the tooling
appropriate for this job (turning disks up to 9" in diameter).
Instinctively I feel that a 3/16 tool is not going to cut it (sorry about
the pun). But am I right?

One of the things of concern is a tool's ability to handle heat. Small
tools dissipate less heat, thus are prone to overheating, and failure.
Same goes for the grind of the tool. Too slender of a cutting edge can also
lead to premature tool failure (assuming HSS).

If you were to machine steel at recommended speeds and feeds, using brazed
carbide, it's possible you could actually soften the silver solder to the
point of tip failure when running small shank tools. Use the largest you
can accommodate, especially if you can move up to 1/2" sizes. They are far
more robust, and should serve better than small tools. Their greater
thickness of carbide, and larger size, are a good offset for the higher
price you will pay. The added rigidity is a bonus.

Harold

I have a boxful of 3/16 and 1/4" tools, toolholders with carbide inserts,
toolposts and something which I take to be a crosslide of some sort into
which all these things fit. They all look rather puny. Would they do a job
of truing up the edge of a 9"x 1/4" disk? Would they face it? Or should I
design around something more beefy? If so, how much more beefy?

--
Michael Koblic,
Campbell River, BC

On Feb 9, 8:51*pm, "Michael Koblic" wrote:
I have sort of worked out the headstock which should spin things as low as
60 rpm.
I am kind of stuck with the tooling side: the carriage, crosslide etc.
One of the questions I am struggling with is the size of the tooling
appropriate for this job (turning disks up to 9" in diameter). Instinctively
I feel that a 3/16 tool is not going to cut it (sorry about the pun). But am
I right?

I have a boxful of 3/16 and 1/4" tools, toolholders with carbide inserts,
toolposts and something which I take to be a crosslide of some sort into
which all these things fit. They all look rather puny. Would they do a job
of truing up the edge of a 9"x 1/4" disk? Would they face it? Or should I
design around something more beefy? If so, how much more beefy?

--
Michael Koblic,
Campbell River, BC

Context? Are you building the redneck lathe?

The 3/4 HP available on my lathe hasn't burned or broken 1/4" HSS bits
yet, possibly because I keep the belts somewhat loose.

Jim Wilkins

"Michael Koblic" wrote in message
...
I have sort of worked out the headstock which should spin things as low as
60 rpm.
I am kind of stuck with the tooling side: the carriage, crosslide etc.
One of the questions I am struggling with is the size of the tooling
appropriate for this job (turning disks up to 9" in diameter).
Instinctively I feel that a 3/16 tool is not going to cut it (sorry about
the pun). But am I right?

I have a boxful of 3/16 and 1/4" tools, toolholders with carbide inserts,
toolposts and something which I take to be a crosslide of some sort into
which all these things fit. They all look rather puny. Would they do a job
of truing up the edge of a 9"x 1/4" disk? Would they face it? Or should I
design around something more beefy? If so, how much more beefy?

--
Michael Koblic,
Campbell River, BC

It's probably related more to HP than swing, and how much of your lathes HP
are you really using. You can do a LOT of very useful work with 3/16 and
especially 1/4 tools.

If you were to machine steel at recommended speeds and feeds, using brazed
carbide, it's possible you could actually soften the silver solder to the
point of tip failure when running small shank tools. *

Been there done that. It can cause an interesting experience if the
carbide gets trapped between the stock and the remaining shank.

JW

On 2009-02-10, Michael Koblic wrote:
I have sort of worked out the headstock which should spin things as low as
60 rpm.
I am kind of stuck with the tooling side: the carriage, crosslide etc.
One of the questions I am struggling with is the size of the tooling
appropriate for this job (turning disks up to 9" in diameter). Instinctively
I feel that a 3/16 tool is not going to cut it (sorry about the pun). But am
I right?

What *material* do you expect to cut? A 3/16" tool would be
fine for aluminum or brass. A bit marginal with bronze, and quite
questionable for steel -- especially tough steel. (This is assuming
that you are talking about the shank of tools mounted in a quick-change
toolpost. In the old style lantern tool post and the forged holders,
1/4 HSS bits would probably be within reason, as the toolpost and holder
offer more give than the tool itself does.

I have a boxful of 3/16 and 1/4" tools, toolholders with carbide inserts,
toolposts and something which I take to be a crosslide of some sort into
which all these things fit. They all look rather puny. Would they do a job
of truing up the edge of a 9"x 1/4" disk? Would they face it? Or should I
design around something more beefy? If so, how much more beefy?

I would judge based on the standard tool holders for a
quick-change toolpost sized to fit the machine. A 9" lathe by South
Bend for example would use an AXA sized quick change toolpost, and the
standard holders for that accept up to 1/2" shanks. I'm using a 12"
swing Clausing, and I use the BXA toolpost which accepts 5/16" shanks in
the standard holders. Larger machines (say 15" swing) would use CXA
which will accept 3/4" shanks. These are pretty much scaled for the
load which the machine will put on them.

FWIW -- my 12" Clausing will go down to 35 RPM in back gear, and
to 210 RPM in direct drive. Most of the time, for what I do with steel,
when I'm in back gear I typically am at the middle speed -- 100 RPM,
though I am likely to go all the way down to 35 RPM when knurling steel.

But all of this assumes that the bed, the cross-slide, and the
compound are made proportional to the swing. Since you appear to be
considering making your own, you need to know how stiff these parts are
made first.

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 ---

Jim Wilkins wrote:

Context? Are you building the redneck lathe?

The 3/4 HP available on my lathe hasn't burned or broken 1/4" HSS bits
yet, possibly because I keep the belts somewhat loose.

You know me far too well!

I just had a go with a jury-rigged system just to see how things behave. I
have had good results with doing the edges by an improvised grinding post
(read: Dremel) but facing is still an issue.

Not needing a tailstock makes things considerably easier. I have an idea of
a crosslide based on $9 drill press vise but before I design it completely I
wanted to make sure that all that little tooling I have in the drawer is
useable in this application.

--
Michael Koblic,
Campbell River, BC

DoN. Nichols wrote:
What *material* do you expect to cut?

Mild steel and brass.

A 3/16" tool would be
fine for aluminum or brass. A bit marginal with bronze, and quite
questionable for steel -- especially tough steel. (This is assuming
that you are talking about the shank of tools mounted in a
quick-change toolpost. In the old style lantern tool post and the
forged holders, 1/4 HSS bits would probably be within reason, as the
toolpost and holder offer more give than the tool itself does.

This has not been finalized by any means. This is the sort of concept I have
in mind:

http://www.majosoft.com/metalworking..._toolpost.html

Not quite sure where the "quick change" comes into it.

I have a boxful of 3/16 and 1/4" tools, toolholders with carbide
inserts, toolposts and something which I take to be a crosslide of
some sort into which all these things fit. They all look rather
puny. Would they do a job of truing up the edge of a 9"x 1/4" disk?
Would they face it? Or should I design around something more beefy?
If so, how much more beefy?

I would judge based on the standard tool holders for a
quick-change toolpost sized to fit the machine. A 9" lathe by South
Bend for example would use an AXA sized quick change toolpost, and the
standard holders for that accept up to 1/2" shanks. I'm using a 12"
swing Clausing, and I use the BXA toolpost which accepts 5/16" shanks
in the standard holders. Larger machines (say 15" swing) would use
CXA which will accept 3/4" shanks. These are pretty much scaled for
the load which the machine will put on them.

FWIW -- my 12" Clausing will go down to 35 RPM in back gear, and
to 210 RPM in direct drive. Most of the time, for what I do with
steel, when I'm in back gear I typically am at the middle speed --
100 RPM, though I am likely to go all the way down to 35 RPM when
knurling steel.

At this point my wife can crank the handle at 120 rpm but will slow down if
asked nicely.

But all of this assumes that the bed, the cross-slide, and the
compound are made proportional to the swing. Since you appear to be
considering making your own, you need to know how stiff these parts
are made first.

This is being currently determined by experiments. The small version - not
very. Produced an interesting pattern of chatter marks on the face. Perhaps
useful in future but not what I was looking for immediately.

--
Michael Koblic,
Campbell River, BC

On Feb 10, 9:03*pm, "Michael Koblic" wrote:
Jim Wilkins wrote:
Context? Are you building the redneck lathe?

The 3/4 HP available on my lathe hasn't burned or broken 1/4" HSS bits
yet, possibly because I keep the belts somewhat loose.

You know me far too well!

I just had a go with a jury-rigged system just to see how things behave. I
have had good results with doing the edges by an improvised grinding post
(read: Dremel) but facing is still an issue.

Not needing a tailstock makes things considerably easier. I have an idea of
a crosslide based on $9 drill press vise but before I design it completely I
wanted to make sure that all that little tooling I have in the drawer is
useable in this application.

--
Michael Koblic,
Campbell River, BC

I started off by milling on the drill press with a cheap X-Y vise. It
worked as poorly as others have said on metal but was OK for making
plastic electrical connector housings. The vise as bought was a flock
of crudely machined parts flying in loose formation. The cast iron was
soft enough to file and stone smooth and carefully adjust to a better
fit without tight or loose spots. I "lapped" the slides with fine SiC
sandpaper.

One of the reasons I suggested Holtzapffel was to show you how
serviceable lathes were made without accurate machined ways in the
early 1800's. The cross slide was a bolt-on accessory that was aligned
to the spindle axis with a simple jig or test bar. For instance if you
want the vise jaw opening perpendicular to the spindle to hold a tool
bit, clamp a long straight bar and tap it parallel to the face plate,
or tram it like a mill. This should align the X and Y axis with the
spindle. You could make a sheet-metal gage that rests on the ways with
a shelf at center height to set tool bits easily.

When I design a machine or a circuit or a program I break it up into
modules first and try to clearly define and minimize their
interaction, without too much concern for the internal details except
for any difficult ones, i.e. the critical path. For a machine I build
the frame and provide a nice flat solid mounting surface wherever I'll
need to add something later. Each module can be assembled and tested
in order of importance and any changes added to the spec list for the
next assembly.

Sometimes a wooden model helps. I made one for my front end loader's
frame to determine clearance for the front wheels and steering
linkage, and assembled the sawmill wheels on 2X4s first before welding
the steel frame.

Jim Wilkins

Jim Wilkins wrote:
... The vise as bought was a flock
of crudely machined parts flying in loose formation. ...

I love it! What wonderful imagery.

Bob

Jim Wilkins wrote:
I started off by milling on the drill press with a cheap X-Y vise. It
worked as poorly as others have said on metal but was OK for making
plastic electrical connector housings. The vise as bought was a flock
of crudely machined parts flying in loose formation. The cast iron was
soft enough to file and stone smooth and carefully adjust to a better
fit without tight or loose spots. I "lapped" the slides with fine SiC
sandpaper.

For $9 I am expecting something very similar. As usual, it has to come from
Calgary...

One of the reasons I suggested Holtzapffel was to show you how
serviceable lathes were made without accurate machined ways in the
early 1800's. The cross slide was a bolt-on accessory that was aligned
to the spindle axis with a simple jig or test bar. For instance if you
want the vise jaw opening perpendicular to the spindle to hold a tool
bit, clamp a long straight bar and tap it parallel to the face plate,
or tram it like a mill. This should align the X and Y axis with the
spindle. You could make a sheet-metal gage that rests on the ways with
a shelf at center height to set tool bits easily.

Great minds (and mine, sometimes) think alike! That is the sort of thing I
am planning. The additional advantages I have over proper machinists are the
absence of necessity to do things to tight tolerances (BTW what are all
those zeros after the decimal point on my calipers for?) and sufficient time
to work on a piece.

BTW Holztapffel is a source of constant inspiration.

When I design a machine or a circuit or a program I break it up into
modules first and try to clearly define and minimize their
interaction, without too much concern for the internal details except
for any difficult ones, i.e. the critical path. For a machine I build
the frame and provide a nice flat solid mounting surface wherever I'll
need to add something later. Each module can be assembled and tested
in order of importance and any changes added to the spec list for the
next assembly.

I am trying to follow a similar path: However, one needs to keep in mind the
project as a whole, all aspects of it, physical, social and economical
included. As I mentioned I think the headstock concept is sorted *but* I do
not want to spend a lot of time and money on it if the concept of tool
application is vague. To exaggerate somewhat, it would make no sense to go
ahead and build the headstock for $100 only to realize that the crosslide
etc. will require additional $500 to complete. I might as well save me some
time and buy the whole thing ready made. Interestingly, I saw some economic
analysis of home-built machine tooling and the sums were more or less
identical to the cost of lower end commercially available machinery. I am
hoping to avoid that pitfall through my incredible ingenuity and foresight.
Failing that, denial.

Sometimes a wooden model helps. I made one for my front end loader's
frame to determine clearance for the front wheels and steering
linkage, and assembled the sawmill wheels on 2X4s first before welding
the steel frame.

The wooden version 1.01 is in operation, version 1.02 should be in progress
tomorrow depending on supplies delivery. BTW has anyone noticed lack of
scrap at local scrap yards? Ours was nearly empty today.

When your wife begins to scream at you: "For God's sake buy the bloody lathe
already!" you know you have become a bit of a bore on the subject (of course
the threat of being asked to turn various handles and her need for a new
iPod go some way to explain this laxity of fiscal policy). Still, I propose
to give it the last shot before I cave in.

--
Michael Koblic,
Campbell River, BC

On 2009-02-11, Michael Koblic wrote:
DoN. Nichols wrote:
What *material* do you expect to cut?

Mild steel and brass.

A 3/16" tool would be
fine for aluminum or brass. A bit marginal with bronze, and quite
questionable for steel -- especially tough steel. (This is assuming
that you are talking about the shank of tools mounted in a
quick-change toolpost. In the old style lantern tool post and the
forged holders, 1/4 HSS bits would probably be within reason, as the
toolpost and holder offer more give than the tool itself does.

This has not been finalized by any means. This is the sort of concept I have
in mind:

http://www.majosoft.com/metalworking..._toolpost.html

Not quite sure where the "quick change" comes into it.

O.K. The "Quick change" here comes from the fact that you have
multiple blocks each with a specific tool mounted in it. The upright
screw near the gold colored post in the drawing at the top sets how high
the tip of the tool is from the surface of the compound. The
counterbore mounted screw at the lower right-hand corner clamps the
block at the split to grip the gold colored cylinder post. So -- you
can loosen the crew a quarter turn, lift the tool off the post, and put
another one on there which is already preset for its height and clamp
the screw in it.

What is missing here is provisions for making sure that each
tool holder slid onto the post is in the same position -- especially so
when you replace a tool holder which you removed earlier in the project
it will have its tip in the same position.

There seem to be provisions to prevent the post itself from
turning, but nothing to assure that the holders always go on in the same
position. So -- for my purposes, it is only part of a quick-change
toolpost.

It does avoid having to put a stack of shim stock under each
tool to raise it to the right height, so that is a major benefit from it
(also present in the Aloris style quick change toolposts which also
assure the position of the tool is always the same.)

Anyway -- if the tools can be used with very little extension,
as shown in the drawing you can get away with bits with smaller shanks,
other than the question of heat transfer which another mentioned.

Note that he frequently says "bold" when he means "bolt", but
that English is not his native language, so it takes a bit of knowledge
to interpret what he says in places.

It looks as though he has the information in several languages,
which makes it an even more impressive task.

[ ... ]

FWIW -- my 12" Clausing will go down to 35 RPM in back gear, and
to 210 RPM in direct drive. Most of the time, for what I do with
steel, when I'm in back gear I typically am at the middle speed --
100 RPM, though I am likely to go all the way down to 35 RPM when
knurling steel.

At this point my wife can crank the handle at 120 rpm but will slow down if
asked nicely.

But -- can she keep up that 120 RPM if you are taking a deep cut
at an 8" radius? :-)

But all of this assumes that the bed, the cross-slide, and the
compound are made proportional to the swing. Since you appear to be
considering making your own, you need to know how stiff these parts
are made first.

This is being currently determined by experiments. The small version - not
very. Produced an interesting pattern of chatter marks on the face. Perhaps
useful in future but not what I was looking for immediately.

O.K.

Good Luck,
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 ---

On Feb 11, 8:42*pm, "Michael Koblic" wrote:
...Interestingly, I saw some economic
analysis of home-built machine tooling and the sums were more or less
identical to the cost of lower end commercially available machinery. I am
hoping to avoid that pitfall through my incredible ingenuity and foresight.

In article ,
"Michael Koblic" wrote:

Jim Wilkins wrote:
I started off by milling on the drill press with a cheap X-Y vise. It
worked as poorly as others have said on metal but was OK for making
plastic electrical connector housings. The vise as bought was a flock
of crudely machined parts flying in loose formation. The cast iron was
soft enough to file and stone smooth and carefully adjust to a better
fit without tight or loose spots. I "lapped" the slides with fine SiC
sandpaper.

For $9 I am expecting something very similar. As usual, it has to come from
Calgary...

One of the reasons I suggested Holtzapffel was to show you how
serviceable lathes were made without accurate machined ways in the
early 1800's. The cross slide was a bolt-on accessory that was aligned
to the spindle axis with a simple jig or test bar. For instance if you
want the vise jaw opening perpendicular to the spindle to hold a tool
bit, clamp a long straight bar and tap it parallel to the face plate,
or tram it like a mill. This should align the X and Y axis with the
spindle. You could make a sheet-metal gage that rests on the ways with
a shelf at center height to set tool bits easily.

Great minds (and mine, sometimes) think alike! That is the sort of thing I
am planning. The additional advantages I have over proper machinists are the
absence of necessity to do things to tight tolerances (BTW what are all
those zeros after the decimal point on my calipers for?) and sufficient time
to work on a piece.

BTW Holztapffel is a source of constant inspiration.

When I design a machine or a circuit or a program I break it up into
modules first and try to clearly define and minimize their
interaction, without too much concern for the internal details except
for any difficult ones, i.e. the critical path. For a machine I build
the frame and provide a nice flat solid mounting surface wherever I'll
need to add something later. Each module can be assembled and tested
in order of importance and any changes added to the spec list for the
next assembly.

I am trying to follow a similar path: However, one needs to keep in mind the
project as a whole, all aspects of it, physical, social and economical
included. As I mentioned I think the headstock concept is sorted *but* I do
not want to spend a lot of time and money on it if the concept of tool
application is vague. To exaggerate somewhat, it would make no sense to go
ahead and build the headstock for $100 only to realize that the crosslide
etc. will require additional $500 to complete. I might as well save me some
time and buy the whole thing ready made. Interestingly, I saw some economic
analysis of home-built machine tooling and the sums were more or less
identical to the cost of lower end commercially available machinery. I am
hoping to avoid that pitfall through my incredible ingenuity and foresight.
Failing that, denial.

Sometimes a wooden model helps. I made one for my front end loader's
frame to determine clearance for the front wheels and steering
linkage, and assembled the sawmill wheels on 2X4s first before welding
the steel frame.

The wooden version 1.01 is in operation, version 1.02 should be in progress
tomorrow depending on supplies delivery. BTW has anyone noticed lack of
scrap at local scrap yards? Ours was nearly empty today.

When your wife begins to scream at you: "For God's sake buy the bloody lathe
already!" you know you have become a bit of a bore on the subject (of course
the threat of being asked to turn various handles and her need for a new
iPod go some way to explain this laxity of fiscal policy). Still, I propose
to give it the last shot before I cave in.

The truth emerges at last - it's all a scheme to convince the CDFO to
allow the purchase.

Joe Gwinn

On Feb 11, 1:43*am, "Michael Koblic" wrote:

http://www.majosoft.com/metalworking..._toolpost.html

Interesting link. I don't know how the author came up with that
design, but you might want to look at the KRF Omnipost, http://www.krfcompany.com/

On Feb 12, 10:10*am, woodworker88 wrote:
On Feb 11, 1:43*am, "Michael Koblic" wrote:

http://www.majosoft.com/metalworking..._toolpost.html

Interesting link. *I don't know how the author came up with that
design, but you might want to look at the KRF Omnipost,http://www.krfcompany.com/

The old lantern / rocker / American style tool post is easy to make
out of a large bolt and much less fussy to use if you mill riser
blocks that locate tool bits or Armstrong-type holders at the correct
height. Don't grind any top rake on the tool bits so the cutting edge
stays at the same level. They won't cut as freely but they will be
less likely to dig in, which is valuable on a flexible home-made
machine.

Jim wilkins

DoN. Nichols wrote:

Not quite sure where the "quick change" comes into it.

O.K. The "Quick change" here comes from the fact that you have
multiple blocks each with a specific tool mounted in it.

big snip

So -- for my purposes, it is only part of a
quick-change toolpost.

I thought I only saw position for one tool hence my doubt about the changes
being all that quick. I can understand when you have four of them.

It does avoid having to put a stack of shim stock under each
tool to raise it to the right height, so that is a major benefit from
it (also present in the Aloris style quick change toolposts which also
assure the position of the tool is always the same.)

The speed of change is not a priority for me, so I can take my time
shimming. It should simplify the design considerably.

Anyway -- if the tools can be used with very little extension,
as shown in the drawing you can get away with bits with smaller
shanks, other than the question of heat transfer which another
mentioned.

I think I can get quite close. The one problem is workholding: The steel
doughnuts are easy to work on the inside edge (boring bar, I think), outside
edge (several methods including my very own red Neck lathe gave good
results) but holding to be able to get to the whole face is a bit tricky. At
this point I have the doughnut on a sort of wooden face plate and it is held
to it by a wooden plug which is ever so slightly conical. Thus it holds the
doughnut through the central hole but does not overhang enough to stop the
tool getting to the whole area of the face. However, with toolposts,
toolholders and crosslide it may be less easy. I am thinking going back to
the double-sided sticky tape with a thin boss sticking out of the centre of
the faceplate to allow indexing and centering. My other thought is magnets
and a similar central boss - it works with the angle grinder...

Of course this will mean making a different faceplate for different
doughnuts but so be it. Another option is to look at central holding by a
3-jaw chuck but I suspect it wil not be a free lunch either.

At this point my wife can crank the handle at 120 rpm but will slow
down if asked nicely.

But -- can she keep up that 120 RPM if you are taking a deep cut
at an 8" radius? :-)

Training is everything. An a new iPod...

--
Michael Koblic,
Campbell River, BC

Jim Wilkins wrote:

The old lantern / rocker / American style tool post is easy to make
out of a large bolt and much less fussy to use if you mill riser
blocks that locate tool bits or Armstrong-type holders at the correct
height. Don't grind any top rake on the tool bits so the cutting edge
stays at the same level. They won't cut as freely but they will be
less likely to dig in, which is valuable on a flexible home-made
machine.

After scurrying to Google to see what these things look like I am not
entirely clear on the advantages of the lantern type holder: Is it because
they can accommodate different styles of tools at different heights (needing
the risers as you mentioned)? Are the tools held at a different angle from
the quick change toolpost? I thought they were both essentially horizontal.

Also, the way the toolbits ar held in the respective toolposts suggests that
the QC holds the bits more rigidly. In the lantern type there is a sort of
fulcrum where the holding screw comes down on the bit. Are you saying this
is actually an advantage in a floppy machine?

--
Michael Koblic,
Campbell River, BC

"Michael Koblic" wrote in message
...
Jim Wilkins wrote:

The old lantern / rocker / American style tool post is easy to make
out of a large bolt and much less fussy to use if you mill riser
blocks that locate tool bits or Armstrong-type holders at the correct
height. Don't grind any top rake on the tool bits so the cutting edge
stays at the same level. They won't cut as freely but they will be
less likely to dig in, which is valuable on a flexible home-made
machine.

After scurrying to Google to see what these things look like I am not
entirely clear on the advantages of the lantern type holder: Is it because
they can accommodate different styles of tools at different heights
(needing the risers as you mentioned)?

Yes, although you won't need risers much. Once you have some toolholders and
a lantern-type toolpost (also known as a rocker-type toolpost, which is the
term you'll find in most of the older professional literature), and use them
for a while, you'll know what angles to grind on your bits.

Although I've used an Aloris toolpost years ago, when I worked in a
commercial shop, my personal lathe has a rocker toolpost, and always has. It
has its limitations, particularly in terms of rigidity necessary for using
carbide tools, but it's quite versatile. You can quickly make small changes
in tool angles and positions, for example. This can be a help in getting
good surface finishes in difficult materials. And you may find that you
didn't grind quite enough front clearance on a tool but that you can set the
tool a tad below center and finish the job without removing the bit and
re-grinding it.

Sometimes you can reach into difficult places easier with a rocker,
particularly for things like recessed face grooves on a flanged part, right
up against the chuck.

Anyway, I'm not trying to sell the rocker toolpost, because the Aloris and
similar types have more advantages, and they're handier. But I disagree with
those who say the rocker toolpost is hopeless. A lot of people have just
never used one enough to be comfortable with them.

Are the tools held at a different angle from the quick change toolpost? I
thought they were both essentially horizontal.

Also, the way the toolbits ar held in the respective toolposts suggests
that the QC holds the bits more rigidly. In the lantern type there is a
sort of fulcrum where the holding screw comes down on the bit. Are you
saying this is actually an advantage in a floppy machine?

I don't want to speak for Jim, but I think that "advantage" is a slight one
at best, which I'll let Jim explain. If you read really old (early
20th-century or before) machinist handbooks you'll see several types of
"spring" tools that were made to work with springy setups. They're long
gone.

--
Ed Huntress

On 2009-02-13, Michael Koblic wrote:
DoN. Nichols wrote:

Not quite sure where the "quick change" comes into it.

O.K. The "Quick change" here comes from the fact that you have
multiple blocks each with a specific tool mounted in it.

big snip

So -- for my purposes, it is only part of a
quick-change toolpost.

I thought I only saw position for one tool hence my doubt about the changes
being all that quick. I can understand when you have four of them.

It one tool per block -- and multiple blocks which slide onto
the cylindrical post which mounts on the lathe's compound.

The screw which adjusts the height of the tool would be right
only for one tool even if you had slots four four tools like a turret
toolpost. So -- each holder has its own height adjusting screw, and
when you change tools, each one lands at the proper height -- assuming
that you set it properly when the tool was first put in the holder. (I
do not remember seeing a lock nut for the height screw, but one really
should be there.

It does avoid having to put a stack of shim stock under each
tool to raise it to the right height, so that is a major benefit from
it (also present in the Aloris style quick change toolposts which also
assure the position of the tool is always the same.)

The speed of change is not a priority for me, so I can take my time
shimming. It should simplify the design considerably.

Hmm ... maybe you should look at a turret toolpost. It has four
slots, and can hold four tools (if all the same orientation, or three
tools if one is set to bore or face because they would otherwise
interfere with each other.

A turret style toolpost is fairly easy to make. Square up a
block of steel, mill four slots at the right height so the cutting edge
of the tool can be raised to the right height with only a few shims.
Drill three holes from the top for screws to lock the tools into the
slots, and drill a larger central hole about which the post pivots when
the locking nut is loosened.

Anyway -- if the tools can be used with very little extension,
as shown in the drawing you can get away with bits with smaller
shanks, other than the question of heat transfer which another
mentioned.

I think I can get quite close. The one problem is workholding: The steel
doughnuts are easy to work on the inside edge (boring bar, I think), outside
edge (several methods including my very own red Neck lathe gave good
results) but holding to be able to get to the whole face is a bit tricky. At
this point I have the doughnut on a sort of wooden face plate and it is held
to it by a wooden plug which is ever so slightly conical. Thus it holds the
doughnut through the central hole but does not overhang enough to stop the
tool getting to the whole area of the face. However, with toolposts,
toolholders and crosslide it may be less easy. I am thinking going back to
the double-sided sticky tape with a thin boss sticking out of the centre of
the faceplate to allow indexing and centering. My other thought is magnets
and a similar central boss - it works with the angle grinder...

Hmm ... what I would suggest is that you get a three-jaw chuck
with two-piece jaws, then pick up a set of soft jaws to fit in place of
the hardened top jaws.

Tighten it onto perhaps a 1/2" diameter bar, and turn the jaws
leaving a projection a little thinner than the workpiece is to be near
the outside end for the smallest plate which you wish to face. Then you
can accommodate several larger sizes with the same set of top jaws just
by opening the chuck more. (Needless to say, the 1/2" diameter bar does
not remain in the chuck while you are using it -- it is only to set the
position of the jaws while you bore and face them.

Of course this will mean making a different faceplate for different
doughnuts but so be it. Another option is to look at central holding by a
3-jaw chuck but I suspect it wil not be a free lunch either.

Central holding will be better (once you have the center hole
bored), but it will be difficult to face right up to the chuck jaws.
Maybe a second set of soft jaws, turned to have a step to hold from the
inside instead. This way, the rest of the jaw's surface supports the
workpiece, so it is less likely to ring like a bell while you are
turning.

Magnets are used to hold workpieces which are being ground, but
don't have enough grip to handle workpieces which are being turned. The
forces are a lot higher.

At this point my wife can crank the handle at 120 rpm but will slow
down if asked nicely.

But -- can she keep up that 120 RPM if you are taking a deep cut
at an 8" radius? :-)

Training is everything. An a new iPod...

:-)

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 ---

On Feb 12, 9:32*pm, "Ed Huntress" wrote:
"Michael Koblic" wrote in message
Jim Wilkins wrote:
The old lantern / rocker / American style tool post is easy to make...

I don't want to speak for Jim, but I think that "advantage" is a slight one
at best, which I'll let Jim explain. If you read really old (early
20th-century or before) machinist handbooks you'll see several types of
"spring" tools that were made to work with springy setups. They're long
gone.
Ed Huntress

Ed described their versatility very well. I made this one from a bolt
to be able to use the lathe:
http://picasaweb.google.com/KB1DAL/T...59874580966978
The initial bootstrap "tool holder" was a strap clamped by bolts and
fender washers trimmed to fit into the tee slot on the compound. The
chain-drilled slot was very rough at first but that didn't matter,
only the spherical washer and the bar that rests on it need to be well
finished. I fitted the bar by smearing blueing on the washer and
repeatedly filing off the contact marks, mostly with a coarse rasp
that left the crosswise lines. The clamp bolt should be hardened or it
will mushroom on the end, as you can see. I will need to grind that
one down with a Dremel to get it out.

Instead of the spherical washer and rocker bar you could use a stack
of large washers or a section of water pipe. A threaded joint cut from
pipe and a fitting would be adjustable for height. As Ed said they
have no real advantage in use, but they are easy to make from common
hardware with simple equipment. That one was turned between centers
and drilled a little crookedly on a drill press.

I still use it occasionally when I need a less bulky tool post, for
instance to turn a ball by swiveling the compound.

This is the tool post I like best, the Multifix, which is quick and
solid like an Aloris but rotates almost like a rocker post. Chinese
clone tool holders from Tools4cheap fit the Swiss center column
perfectly.
http://picasaweb.google.com/KB1DAL/H...33382447691698
I found it for $50 while on a treasure hunt for a used Aloris or new
Phase II.

Jim Wilkins

On 2009-02-13, Michael Koblic wrote:
Jim Wilkins wrote:

The old lantern / rocker / American style tool post is easy to make
out of a large bolt and much less fussy to use if you mill riser
blocks that locate tool bits or Armstrong-type holders at the correct
height. Don't grind any top rake on the tool bits so the cutting edge
stays at the same level. They won't cut as freely but they will be
less likely to dig in, which is valuable on a flexible home-made
machine.

After scurrying to Google to see what these things look like I am not
entirely clear on the advantages of the lantern type holder:

They are a very old design. They originally held high carbon
steel tools which were shaped in a forge to provide the needed tip
orientation, and then hardened by quenching and (likely) tempering.

Later, there were forged steel holders for the standard square
HSS lathe bits. Armstrong was the originator (I think). They were
available with the bit pointed straight ahead, bent to the left (for
working on the right-hand end of the workpiece), and bent to the right
(for working on the left-hand end of the workpiece.

The HSS bits were put into square holes broached through the
forging. The holes were tilted to produce rake, so you did not have to
weaken the HSS toolbit by grinding rake on the tip, since the HSS bits
were a lot smaller than the original tools.

Later, when brazed carbide tools came into use, there was
another series with the broached hole horizontal instead of providing
rake.

But the original thing which make the Lantern style toolpost and
the holders quite popular was the ease of making the toolpost, and the
ability to raise or lower the tip by tilting the rocker.

But they did lack rigidity -- one of the things which made
turret toolposts, and later quick-change toolposts popular.

Is it because
they can accommodate different styles of tools at different heights (needing
the risers as you mentioned)?

At the bottom of the toolpst is a segment of a disk of steel
(similar to a Woodruff key) which rests on a ring with a section of a
negative sphere turned into it. This allows tilting the tip up and
down, adjusting the height (but with the disadvantage of also changing
the rake angle).

Metal shapers use a lantern style toolpost -- but with a totally
level ring around it -- no tilting, because that is handled by the
clapper box on which the post is mounted.

Are the tools held at a different angle from
the quick change toolpost? I thought they were both essentially horizontal.

Nope -- the HSS bits in Armstrong style toolholders in a lantern
style toolpost are tilted to produce a rake without having to grind one
into the bit. The quick change toolpost is normally used with carbide
insert tools, so the carbide can be used with zero rake from the post
and the holders for the inserts introduce either zero rake or negative
rake, depending on the insert in use. Brazed inserts all have zero rake
as far as I know.

Also, the way the toolbits ar held in the respective toolposts suggests that
the QC holds the bits more rigidly.

Yes it does -- significantly.

In the lantern type there is a sort of
fulcrum where the holding screw comes down on the bit. Are you saying this
is actually an advantage in a floppy machine?

Just not as much of a disadvantage on a floppy machine, because
the machine is already contributing enough flop for everyone. :-)

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 ---

"DoN. Nichols" wrote in message
...
snip-.

Hmm ... maybe you should look at a turret toolpost. It has four
slots, and can hold four tools (if all the same orientation, or three
tools if one is set to bore or face because they would otherwise
interfere with each other.

I've used an O.K. Rubber Welders square indexing tool post for years. I
prefer the design over the quick change holders, but only for small work.
If you mount a boring bar with a short shank, and the work is small, you
can still mount four tools. I've even crowded five tools in a setup,
although the fifth tool was mounted at a strange angle, held only with one
screw, and was used strictly for chamfering. The OK tool block offers
positive indexing @ 3 degree increments.

Harold

"Ed Huntress" wrote in message
...
snip---

Anyway, I'm not trying to sell the rocker toolpost, because the Aloris and
similar types have more advantages, and they're handier. But I disagree
with those who say the rocker toolpost is hopeless. A lot of people have
just never used one enough to be comfortable with them.

Fact is, it has little to do with comfort. A rocker tool post does not
allow for production machining. They are totally worthless for that
purpose, which is why they are not found in industry. They are
flexible in that you can achieve pretty much any angle of approach to the
job, but you can't mark dials and make time with them. I would avoid a rock
toolpost at almost any cost, assuming I had intentions of making more than
one of anything.

Harold

"DoN. Nichols" wrote in message
...
Hmm ... what I would suggest is that you get a three-jaw chuck
with two-piece jaws, then pick up a set of soft jaws to fit in place of
the hardened top jaws.

Tighten it onto perhaps a 1/2" diameter bar, and turn the jaws
leaving a projection a little thinner than the workpiece is to be near
the outside end for the smallest plate which you wish to face. Then you
can accommodate several larger sizes with the same set of top jaws just
by opening the chuck more. (Needless to say, the 1/2" diameter bar does
not remain in the chuck while you are using it -- it is only to set the
position of the jaws while you bore and face them.

I thought I could achieve pretty similar result by shimming the workpiece so
it sits higher up in the jaws. I tried it with the chuck on the table and it
seemed to look OK. Of course looking is one thing and turning is another...

Of course this will mean making a different faceplate for different
doughnuts but so be it. Another option is to look at central holding by a
3-jaw chuck but I suspect it wil not be a free lunch either.

Central holding will be better (once you have the center hole
bored), but it will be difficult to face right up to the chuck jaws.
Maybe a second set of soft jaws, turned to have a step to hold from the
inside instead. This way, the rest of the jaw's surface supports the
workpiece, so it is less likely to ring like a bell while you are
turning.

Magnets are used to hold workpieces which are being ground, but
don't have enough grip to handle workpieces which are being turned. The
forces are a lot higher.

Even grinding I do not rely on the magnets alone. That is where the central
boss comes in. It stops the lateral movement of the piece. The magnets (4 of
them) stop the vertical movement. I was hoping that the combination might
work for facing if the boss is sufficiantly tight inside the doughnut hole.


--
Michael Koblic,
Campbell River, BC

Jim Wilkins wrote:
On Feb 12, 9:32 pm, "Ed Huntress" wrote:
"Michael Koblic" wrote in message
Jim Wilkins wrote:
The old lantern / rocker / American style tool post is easy to
make...

I don't want to speak for Jim, but I think that "advantage" is a
slight one at best, which I'll let Jim explain. If you read really
old (early 20th-century or before) machinist handbooks you'll see
several types of "spring" tools that were made to work with springy
setups. They're long gone.
Ed Huntress

Looking in Advanced Machine Work that seemed to be the only toolpost then.
In fact they do not discuss toolposts much at all.

Ed described their versatility very well. I made this one from a bolt
to be able to use the lathe:
http://picasaweb.google.com/KB1DAL/T...59874580966978
The initial bootstrap "tool holder" was a strap clamped by bolts and
fender washers trimmed to fit into the tee slot on the compound. The
chain-drilled slot was very rough at first but that didn't matter,
only the spherical washer and the bar that rests on it need to be well
finished. I fitted the bar by smearing blueing on the washer and
repeatedly filing off the contact marks, mostly with a coarse rasp
that left the crosswise lines. The clamp bolt should be hardened or it
will mushroom on the end, as you can see. I will need to grind that
one down with a Dremel to get it out.

OK. In the picture the rocker bar is "upside down". Now I see why they
called it a rocker toolpost. In a lot of the literature and web references
this feature is by no means obvious.

Looking at it I wonder if the slot was milled in the threaded part of the
bolt could one not use a nut or two to adjust the height of the tool?
Aslo, how is the toolpost held on the crosslide? I take it there is a
capscrew that goes through the hole in the bottom and screws into a tee-nut
which then goes into a tee-slot? Or does the whole thing screw down directly
into a taped hole in the crosslide (or compound)? Given the nature of the
rocker bar and its position the capscrew length must be fairly critical so
that it is long enough and not too long to interfere with the bar.

Instead of the spherical washer and rocker bar you could use a stack
of large washers or a section of water pipe. A threaded joint cut from
pipe and a fitting would be adjustable for height. As Ed said they
have no real advantage in use, but they are easy to make from common
hardware with simple equipment. That one was turned between centers
and drilled a little crookedly on a drill press.

I still use it occasionally when I need a less bulky tool post, for
instance to turn a ball by swiveling the compound.

This is the tool post I like best, the Multifix, which is quick and
solid like an Aloris but rotates almost like a rocker post. Chinese
clone tool holders from Tools4cheap fit the Swiss center column
perfectly.
http://picasaweb.google.com/KB1DAL/H...33382447691698
I found it for $50 while on a treasure hunt for a used Aloris or new
Phase II.

In all honesty I think I am jumping ahead of myself. I think the first
toolpost will be something very simple

http://www.metalwebnews.org/mr-tools...ng%20lathe.pdf (page 6)

just to establish that the concept actually works. However, I now know more
than I did before and when (if) it comes to making a permanent toolpost the
choice will be easier

--
Michael Koblic,
Campbell River, BC.

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

"Ed Huntress" wrote in message
...
snip---

Anyway, I'm not trying to sell the rocker toolpost, because the Aloris
and similar types have more advantages, and they're handier. But I
disagree with those who say the rocker toolpost is hopeless. A lot of
people have just never used one enough to be comfortable with them.

Fact is, it has little to do with comfort. A rocker tool post does not
allow for production machining. They are totally worthless for that
purpose, which is why they are not found in industry.

Well, if you're doing production turning in industry, a recreational crafts
newsgroup may not be the best place to ask about toolposts. d8-)

They are flexible in that you can achieve pretty much any angle of approach
to the job, but you can't mark dials and make time with them. I would
avoid a rock toolpost at almost any cost, assuming I had intentions of
making more than one of anything.

Harold

I'll remember that the next time I do a production run in my basement.

--
Ed Huntress

On Fri, 13 Feb 2009 23:00:00 -0800, "Michael Koblic"
wrote:
snip
Looking at it I wonder if the slot was milled in the threaded part of the
bolt could one not use a nut or two to adjust the height of the tool?
snip
Check the back issues of the "Home Shop Machinist" or
"Machinist's Workshop" for exactly this project. IIRC this was
called a Swiss type holder.
http://www.homeshopmachinist.net/

You might want to take a look at the KRF "omnipost" plans/kits.
You can make these with only a lathe [with milling attachment]
and a hacksaw. I made these and they work fine. You may want to
buy the notched index plate that goes under the tool post as this
can be difficult to make, but these are not expensive.
http://www.krfcompany.com/





Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

On Sat, 14 Feb 2009 11:49:26 -0600, F. George McDuffee
wrote:
snip
You might want to take a look at the KRF "omnipost" plans/kits.
You can make these with only a lathe [with milling attachment]
and a hacksaw. I made these and they work fine. You may want to
buy the notched index plate that goes under the tool post as this
can be difficult to make, but these are not expensive.
http://www.krfcompany.com/
snip
If this looks interesting, I came across this website showing
step by step procedure during another search.

http://www.majosoft.com/metalworking..._toolpost.html

FWIW -- The first few holders I made were before I bought the KRF
plans. [I don't know if KDF still sells these] These worked well
enough, but the screw sizes are such that I need two sets of hex
keys to adjust. With the plans and the specified hex screws, you
only need the single set.
http://www.use-enco.com/CGI/INSRIT?P...PARTPG=INLMK32


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

On Feb 14, 2:00*am, "Michael Koblic" wrote:
Jim Wilkins wrote:
On Feb 12, 9:32 pm, "Ed Huntress" wrote:
"Michael Koblic" wrote in message
Jim Wilkins wrote:

Looking at it I wonder if the slot was milled in the threaded part of the
bolt could one not use a nut or two to adjust the height of the tool?
Aslo, how is the toolpost held on the crosslide? I take it there is a
capscrew that goes through the hole in the bottom and screws into a tee-nut
which then goes into a tee-slot? Or does the whole thing screw down directly
into a taped hole in the crosslide (or compound)? Given the nature of the
rocker bar and its position the capscrew length must be fairly critical so
that it is long enough and not too long to interfere with the bar.

Don't redesign it before you understand it. The flange on the lower
end fits into the tee slot on the compound. The top screw clamps the
washer, rocker and tool bit/holder solidly down onto the top of the
compound, meaning that you have to readjust it all if you loosen that
screw. You use the tailstock center point or an experienced eyeball
estimate against a chuck jaw or the work to set the cutting edge
height. Hopefully you won't use one long enough to become an expert.

In all honesty I think I am jumping ahead of myself. I think the first
toolpost will be something very simple

http://www.metalwebnews.org/mr-tools...ng%20lathe.pdf (page 6)
Michael Koblic,
Campbell River, BC

The strap+bolts is how I turned the rocker post. I would have 4 tapped
holes in a square so the bit could be set closer to parallel with the
ways, to bore the center hole for instance, and to put a second strap
further back for improved leverage.

Carriage bolts are easier than hex heads to modify into tee slot
studs . File a washer to almost fit the square and pound it on, trim
it to the slot width and grind the head thinner if necessary.

A disadvantage of that design is the fixed height of the tool bit
which as shown doesn't allow Armstrong-style holders. If you find
some, and you should look, you will need shims to set the bit on
center. A stack of small thin shims is a royal pain since you have
only one hand to hold them in place while tightening the clamp screws
with the other.

With the turret or KRF styles you don't have to shim and clamp the bit
as often, only when you change or regrind it.

The rocker post avoids small shims by tilting the holder, which also
changes the effective front and top rake of the cutting edge. It will
hold naked tool bits if you block them up with bar stock or other tool
bits. Neither type is ideal but either will get you started.

Jim Wilkins

On 2009-02-14, Michael Koblic wrote:

"DoN. Nichols" wrote in message
...
Hmm ... what I would suggest is that you get a three-jaw chuck
with two-piece jaws, then pick up a set of soft jaws to fit in place of
the hardened top jaws.

Tighten it onto perhaps a 1/2" diameter bar, and turn the jaws
leaving a projection a little thinner than the workpiece is to be near
the outside end for the smallest plate which you wish to face. Then you
can accommodate several larger sizes with the same set of top jaws just
by opening the chuck more. (Needless to say, the 1/2" diameter bar does
not remain in the chuck while you are using it -- it is only to set the
position of the jaws while you bore and face them.

I thought I could achieve pretty similar result by shimming the workpiece so
it sits higher up in the jaws. I tried it with the chuck on the table and it
seemed to look OK. Of course looking is one thing and turning is another...

It is tricky doing this. You need a set of parallels of the
right size to support it -- or an aluminum extrusion "spider" which fits
between the chuck jaws and holds itself in place with magnets gripping
the chuck body face.

The spiders are neat -- but are rather expensive for what they
are.

The parallels must be removed before you spin up the chuck -- or
they are likely to hit you somewhere.

The advantage of turning soft jaws for the purpose is that you
will have support over most of the radius of the workpiece. Your
workpieces are fairly thin and would be likely to ring. Hmm ... if you
make the soft jaws from aluminum, you can embed permanent magnets in the
end away from the gripping step. (You will have problems with the chips
from steel piling up on the magnets, however. For brass or aluminum, no
problem. But good strong magnets in the jaws will help to control
ringing, and since you are going to be doing this a lot, it is worth
while making proper tooling for the task.

Of course -- there are also pie wedge soft jaws, which form an
nearly complete circle when the chuck jaws are at the tightest setting,
and those can be turned for your workpieces. You can even turn several
diameters working as steps from shallow at the OD to deep at the ID, so
progressively smaller discs can be gripped.

Of course this will mean making a different faceplate for different
doughnuts but so be it. Another option is to look at central holding by a
3-jaw chuck but I suspect it wil not be a free lunch either.

Your "doughnuts" are actually disks not things thick enough to be
proportional for a doughnut, aren't they? Say an 8" disk perhaps 1/4"
thick or so?

Central holding will be better (once you have the center hole
bored), but it will be difficult to face right up to the chuck jaws.
Maybe a second set of soft jaws, turned to have a step to hold from the
inside instead. This way, the rest of the jaw's surface supports the
workpiece, so it is less likely to ring like a bell while you are
turning.

Magnets are used to hold workpieces which are being ground, but
don't have enough grip to handle workpieces which are being turned. The
forces are a lot higher.

Even grinding I do not rely on the magnets alone. That is where the central
boss comes in. It stops the lateral movement of the piece. The magnets (4 of
them) stop the vertical movement. I was hoping that the combination might
work for facing if the boss is sufficiantly tight inside the doughnut hole.

I'll bet that you will find that the magnets are not strong
enough for turning -- the workpiece will spin around the boss.

Good Luck,
DoN.

--
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--- Black Holes are where God is dividing by zero ---

On 2009-02-14, Michael Koblic wrote:
Jim Wilkins wrote:

[ ... ]

Looking in Advanced Machine Work that seemed to be the only toolpost then.
In fact they do not discuss toolposts much at all.

Because there was only one common choice back then. It was when
production lathes like turret lathes came along where the ability to
quickly change the tools and have them repeatably positioned became
important. First, indexed turret toolposts, later quick change
toolposts of various sorts.

Ed described their versatility very well. I made this one from a bolt
to be able to use the lathe:
http://picasaweb.google.com/KB1DAL/T...59874580966978
The initial bootstrap "tool holder" was a strap clamped by bolts and
fender washers trimmed to fit into the tee slot on the compound. The
chain-drilled slot was very rough at first but that didn't matter,
only the spherical washer and the bar that rests on it need to be well
finished. I fitted the bar by smearing blueing on the washer and
repeatedly filing off the contact marks, mostly with a coarse rasp
that left the crosswise lines. The clamp bolt should be hardened or it
will mushroom on the end, as you can see. I will need to grind that
one down with a Dremel to get it out.

OK. In the picture the rocker bar is "upside down". Now I see why they
called it a rocker toolpost. In a lot of the literature and web references
this feature is by no means obvious.

:-)

Looking at it I wonder if the slot was milled in the threaded part of the
bolt could one not use a nut or two to adjust the height of the tool?

I've got some small ones designed for Unimat lathes which have a
two-part ring without the rocker feature. You adjust it for the needed
height by turning the top part which is threaded into the bottom part.
The bottom ring has a raised part which engages the T-slot so it will
not turn while you turn the top part.

Aslo, how is the toolpost held on the crosslide? I take it there is a
capscrew that goes through the hole in the bottom and screws into a tee-nut
which then goes into a tee-slot? Or does the whole thing screw down directly
into a taped hole in the crosslide (or compound)? Given the nature of the
rocker bar and its position the capscrew length must be fairly critical so
that it is long enough and not too long to interfere with the bar.

Looking at the image in the URL left quoted above, look at the
bottom of the toolpost. It is turned to a diameter and thickness so it
fits into the T-slot cleanly. The ring and rocker press on the top of
the compound when the tool holder is clamped in place by the screw at
the top. The traditional ones had a square head screw with a flange so
standard wrenches which also fit other clamp screws and such could rest
on the top of the screw for easy access when you need to change
something. Once you clamp down with the screw, everything is firmly
held in place.

I've seen some with a two-part base -- the round one shown
there, and a rectangular one with a counterbore to accept the round base
of the normal toolpost. This is done mostly (I think) to adapt a
smaller toolpost to a larger lathe compound.

Instead of the spherical washer and rocker bar you could use a stack
of large washers or a section of water pipe. A threaded joint cut from
pipe and a fitting would be adjustable for height.

Similar to (but cruder than) the one for the Unimat which I
have.

As Ed said they
have no real advantage in use, but they are easy to make from common
hardware with simple equipment. That one was turned between centers
and drilled a little crookedly on a drill press.

And the "between centers" explains the apparent hole in the
center of the bottom -- it was for making the post, not for a screw to
secure the post in place.

[ ... ]

This is the tool post I like best, the Multifix, which is quick and
solid like an Aloris but rotates almost like a rocker post. Chinese
clone tool holders from Tools4cheap fit the Swiss center column
perfectly.
http://picasaweb.google.com/KB1DAL/H...33382447691698
I found it for $50 while on a treasure hunt for a used Aloris or new
Phase II.

That is a steal! How many tool holders came with it for that
price?

In all honesty I think I am jumping ahead of myself. I think the first
toolpost will be something very simple

http://www.metalwebnews.org/mr-tools...ng%20lathe.pdf (page 6)

just to establish that the concept actually works. However, I now know more
than I did before and when (if) it comes to making a permanent toolpost the
choice will be easier

O.K. The whole design of the lathe shown there is rather crude,
but should work for light cutting at least.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
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--- Black Holes are where God is dividing by zero ---

On Sat, 14 Feb 2009 11:49:26 -0600, F. George McDuffee
wrote:
snip
Check the back issues of the "Home Shop Machinist" or
"Machinist's Workshop" for exactly this project. IIRC this was
called a Swiss type holder.
http://www.homeshopmachinist.net/
snip

I checked my back issues and the article you want is

St. Louis, C. (2007 August/September). "New Light for your
Lantern Tool Post." Machinist's Workshop, 20.4, 6-15.

The article shows the standard rocker style tool holder and how
that works as well as showing an improved height adjustable
feature, which can incorporate the existing ring/rocker if
desired, but not required.

Note that there is no modification to the tool post or lathe if
this is a consideration.

The "Swiss" reference I recalled was to a Schablin manual
toolroom lathe.

Some cautions:

As is common in many hobby projects, the machining appears to be
more elaborate than necessary, and some avoidable problems are
created by buying material close to the finished sizes, leaving
no room for "service flanges" used to hold the work while
machining, but which are turned off, or the part parted off as
the last operation.

Three specific examples:

(1) The milled anti-rotation flats on the adjuster screw/sleeve
that fits over the tool post are not required. A much simpler
anti rotation solution is to drill and tap holes in the proper
location and install small [#8/#10] SHCSs. This eliminates the
need for a milling machine or lathe milling attaintment for this
part, although precision layout and careful drilling, possibly on
the lathe faceplate will be required for a close fit in the
compound [top] slide T slot. Get sufficient length of material
[1_3/4 OD + tool post ID + c. 0.010/0.020 [or solid] X 4 to 5
inches] to clamp in the three jaw, and part off the completed
part. This is an external 1_3/4 X 20 thread. For our
international participants I am sure that a 1.25 or 1 MM thread
will work as well. If you face the part, drill and bore the part,
externally thread the part, and then part off the part [c. 5/8
but your lathe may require different thickness], this will insure
that the faces are parallel and the thread is perpendicular to
the faces.

(2) While the vertical fluting on the adjusting nut is very
elegant looking, and I am sure works well, it requires a milling
machine and dividing head. A good coarse knurl will provide the
same function, and no finish at all may well be adequate. At the
very least a knurl eliminates the need for a milling machine and
dividing head, and it may well be possible to skip this step
entirely.

(3) If a longer piece [4-5 inches] of heavy tubing or even a
solid bar is purchased for the adjusting nut [2.75 OD X 1.70 ID],
it can be clamped in the three jaw chuck. This will have an
external knurl [or possibly nothing] with an internal 1_3/4 X 20
thread. I strongly recommend that you bore/drill the hole
through or at much deeper than required, and cut a recess/relief
for the tool to feed into. While it is possible to thread to the
bottom of a blind hole [after many years of practice] it is much
easier with through hole. If you face the part, drill bore, and
thread the part, and then part off the part [5/8 thick], this
will insure that the faces are parallel and the threads
perpendicular to the faces.

Good luck with your project, and let the group know what you
discover and how you make out.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

DoN. Nichols wrote:
It is tricky doing this. You need a set of parallels of the
right size to support it -- or an aluminum extrusion "spider" which
fits between the chuck jaws and holds itself in place with magnets
gripping the chuck body face.

Also, different parallels for different thickness pieces. The current method
of holding looks better all the time :-)

The spiders are neat -- but are rather expensive for what they
are.

The parallels must be removed before you spin up the chuck -- or
they are likely to hit you somewhere.

You are right. That might damage them!

Of course this will mean making a different faceplate for different
doughnuts but so be it. Another option is to look at central
holding by a 3-jaw chuck but I suspect it wil not be a free lunch
either.

Your "doughnuts" are actually disks not things thick enough to be
proportional for a doughnut, aren't they? Say an 8" disk perhaps 1/4"
thick or so?

That is right. The most common ones are 4.5" OD with a 2.1" ID and about
0.19" thickness (that varies quite a bit). But I have some with
5.5"/3.2"/0.25" on deck and some even bigger. So far none larger than 7.5"
OD. Although my biggest piece was 12" OD it is unlikely I shall be doing
something that size in the near future for various reasons.

Central holding will be better (once you have the center hole
bored), but it will be difficult to face right up to the chuck jaws.

Here is where I was thinking the other way: Face as close to the centre as
possible. Then bore out the "dirty" bit...

Even grinding I do not rely on the magnets alone. That is where the
central boss comes in. It stops the lateral movement of the piece.
The magnets (4 of them) stop the vertical movement. I was hoping
that the combination might work for facing if the boss is
sufficiantly tight inside the doughnut hole.

I'll bet that you will find that the magnets are not strong
enough for turning -- the workpiece will spin around the boss.

No takers!

--
Michael Koblic,
Campbell River, BC

F. George McDuffee wrote:
On Fri, 13 Feb 2009 23:00:00 -0800, "Michael Koblic"
wrote:
snip
Looking at it I wonder if the slot was milled in the threaded part
of the bolt could one not use a nut or two to adjust the height of
the tool?
snip
Check the back issues of the "Home Shop Machinist" or
"Machinist's Workshop" for exactly this project. IIRC this was
called a Swiss type holder.
http://www.homeshopmachinist.net/

You might want to take a look at the KRF "omnipost" plans/kits.
You can make these with only a lathe [with milling attachment]
and a hacksaw.

I got the hacksaw...But thanks for the detailed information here and in your
next two posts. I shall keep them for future reference. They will be very
useful.

--
Michael Koblic,
Campbell River, BC

Jim Wilkins wrote:

Don't redesign it before you understand it. The flange on the lower
end fits into the tee slot on the compound. The top screw clamps the
washer, rocker and tool bit/holder solidly down onto the top of the
compound, meaning that you have to readjust it all if you loosen that
screw. You use the tailstock center point or an experienced eyeball
estimate against a chuck jaw or the work to set the cutting edge
height. Hopefully you won't use one long enough to become an expert.

OK. I think Don explains the hole in the bottom further on. The "between the
centres" bit...

In all honesty I think I am jumping ahead of myself. I think the
first toolpost will be something very simple

http://www.metalwebnews.org/mr-tools...ng%20lathe.pdf
(page 6) Michael Koblic,
Campbell River, BC

The strap+bolts is how I turned the rocker post. I would have 4 tapped
holes in a square so the bit could be set closer to parallel with the
ways, to bore the center hole for instance, and to put a second strap
further back for improved leverage.

Carriage bolts are easier than hex heads to modify into tee slot
studs . File a washer to almost fit the square and pound it on, trim
it to the slot width and grind the head thinner if necessary.

I got good at that when I discovered that my new drill press t-slots did not
take the common t-nuts. Why do the Chinese like 7/16" so much?

A disadvantage of that design is the fixed height of the tool bit
which as shown doesn't allow Armstrong-style holders. If you find
some, and you should look, you will need shims to set the bit on
center. A stack of small thin shims is a royal pain since you have
only one hand to hold them in place while tightening the clamp screws
with the other.

With the turret or KRF styles you don't have to shim and clamp the bit
as often, only when you change or regrind it.

The rocker post avoids small shims by tilting the holder, which also
changes the effective front and top rake of the cutting edge. It will
hold naked tool bits if you block them up with bar stock or other tool
bits. Neither type is ideal but either will get you started.

Thanks.

--
Michael Koblic,
Campbell River, BC

DoN. Nichols wrote:

big snip

In all honesty I think I am jumping ahead of myself. I think the
first toolpost will be something very simple

http://www.metalwebnews.org/mr-tools...ng%20lathe.pdf
(page 6)

just to establish that the concept actually works. However, I now
know more than I did before and when (if) it comes to making a
permanent toolpost the choice will be easier

O.K. The whole design of the lathe shown there is rather crude,
but should work for light cutting at least.

I think I am about to re-define "crude"...

--
Michael Koblic,
Campbell River, BC

On Sat, 14 Feb 2009 14:40:25 -0800, "Michael Koblic"
wrote:

I got good at that when I discovered that my new drill press t-slots did not
take the common t-nuts. Why do the Chinese like 7/16" so much?
------
Because this is not 7/16. It is a standard metric size T-slot
that 7/16 happens to fit.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

On Feb 14, 3:54*pm, "DoN. Nichols" wrote:
On 2009-02-14, Michael Koblic wrote:
"DoN. Nichols" wrote in message

Of course -- there are also pie wedge soft jaws, which form an
nearly complete circle when the chuck jaws are at the tightest setting,
and those can be turned for your workpieces. You can even turn several
diameters working as steps from shallow at the OD to deep at the ID, so
progressively smaller discs can be gripped.

Pie jaws:
http://picasaweb.google.com/KB1DAL/T...90941151914594
That chuck opens and closes only about 0.050" total, so the jaw steps
have to be quite close to the size of the work. It's nice for lens
rings etc but not for general work. The internal mechanism is slanted
bar cams as shown in an early Holtzapffel drawing.

Your 3-jaw shims can be rings cut from plywood or discarded plates
with a scroll saw.

I make pulley and other wheels on a plywood-covered faceplate. First I
drill a small center hole for a locating & centering pin. Then I
attach the blank to the plywood with screws in the waste areas and
turn the friction-reducing recess between the rim and the hub on both
sides, using the pin to recenter the blank. This is equivalent to you
facing both sides, BEFORE turning the OD and ID.

If you want a bevel around the inner hole you could cut a shallow
recess where the hole will be and bevel its edge, leaving the center
to support the disk.

Next space the disk out from the plywood with collars on the screws,
in your case probably the inner ones, and turn the OD.

Add a ring of screws and collars around the OD, with washers under the
heads to spread the grip and protect the finish. Cut the center loose
by wiggling the bit sideways slightly for clearance as you run it
toward the headstock. This should work on the OD as well, with the
benefit that the outer screws support the blank better. The bit I use
for this plunge cut is rounded on the end with parallel sides, both
relieved to cut. I use it for the cable groove too.

Or reverse it, bore the center first and clamp the disk to the plywood
with a plate larger than the hole and again the spacers on the screws
to support the disk. This way will be harder to assemble but safer.

The best way might be to attach a temporary wooden block to the center
and turn it to fit the bored ID snugly, then screw another clamping
plate over it to sandwich the disk. Then the disk could slip without
causing a problem when you turn the OD. The lathe's tailstock does a
fair job of clamping the outer plate.

Use brass or soft steel screws, NOT sheetrock screws which are
hardened.

You could make clamps out of small short bars drilled through the
center for the clamp screw and tapped through the outer end for a
stand-off screw to make them sit flat on the disk. Be careful, they
grab clothing.

The spacer collars are easier to mill than turn to identical length.
They don't have to be cylindrical, cross-drilled bar stock is fine.

My lathe will take collets and a faceplate simultaneously, so I center
the blank with the locating pin in a collet and then attach it to the
faceplate. Unscrewing the faceplate pops out the collet adapter.

Hals und beinbruch,

Jim Wilkins