The task is to make end mill holders for my "Eklind" vertical mill head,
that uses collets similar to a Bridgeport B3 (sort of a shrunk R8).

A sketch of a collet that would fit can be seen he

http://metalworking.com/DropBox/_1999_retired_files/UNKNOWN_collet.jpg

My material is 12L14 bar, about 4" long.
The lathe is a SB 9 Mod C., without a toolpost grinder.
I will be using a B3 collet as the template for the draw angle.

What order of operations will maintain concentricity as I drill, turn,
bore and ream?


Thanks,

Kevin Gallimore

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"axolotl" wrote in message
...
The task is to make end mill holders for my "Eklind" vertical mill head,
that uses collets similar to a Bridgeport B3 (sort of a shrunk R8).

A sketch of a collet that would fit can be seen he

http://metalworking.com/DropBox/_1999_retired_files/UNKNOWN_collet.jpg

My material is 12L14 bar, about 4" long.
The lathe is a SB 9 Mod C., without a toolpost grinder.
I will be using a B3 collet as the template for the draw angle.

What order of operations will maintain concentricity as I drill, turn,
bore and ream?


Thanks,

Kevin Gallimore

Long term, the material choice isn't very good, but it will machine
beautifully and yield good finishes. It's desirable for collets to be heat
treated for longevity.

Be certain to set your compound angle before embarking on the process----so
you don't have to remove the collet from your chuck once you've started
machining it. Make certain that your indicator is in the same plain (on
center) as the cutting tool if you choose to set the angle that way,
otherwise the angle the machine yields won't be the same as the one you
want. The collet would be made with the holding end out, even if you have
to do a second operation on the back side for the thread. That isn't
critical to the function, so even if you're slightly eccentric, no big deal.

Regards process, the one thing you should do is rough all features (except
for the slots) before thinking about finishing any of them. That way you'll
have relieved, as much as possible, all the stress inherent in the material
from the rolling process. Leave somewhere between .03"/.05" on the diameter
for finish cuts. Sequence isn't as important as the roughing and finish
cuts are. Drill your hole undersized and bore for concentricity---and
turn all features inside and out that are possible in the same setup. By
having roughed first, then finishing without removing the collet, everything
should come out as true as your machine. Cut your slots last, after you've
tapped the thread. Any changes at that point will be self correcting when
the collet is in use. Deburr the slots well, naturally. Does this make
sense? Need more info?

Harold

On Tue, 31 Jan 2006 20:02:19 -0800, "Harold and Susan Vordos"
wrote:


"axolotl" wrote in message
...
The task is to make end mill holders for my "Eklind" vertical mill head,
that uses collets similar to a Bridgeport B3 (sort of a shrunk R8).

A sketch of a collet that would fit can be seen he

http://metalworking.com/DropBox/_1999_retired_files/UNKNOWN_collet.jpg

My material is 12L14 bar, about 4" long.
The lathe is a SB 9 Mod C., without a toolpost grinder.
I will be using a B3 collet as the template for the draw angle.

What order of operations will maintain concentricity as I drill, turn,
bore and ream?


Thanks,

Kevin Gallimore

snip good stuff
Cut your slots last, after you've
tapped the thread. Any changes at that point will be self correcting when
the collet is in use. Deburr the slots well, naturally. Does this make
sense? Need more info?

Harold


Except he said end mill holder, so he won't need the slots. Substitute
drill and tap setscrew holes last. I've got the same job when I get
my M-head with B3 collets up and running. Also 5C end mill holders
for the TM.

Pete Keillor

Pete sez:
" Except he said end mill holder, so he won't need the slots. Substitute
drill and tap setscrew holes last. I've got the same job when I get
my M-head with B3 collets up and running. Also 5C end mill holders
for the TM."

Yeah but, the drop box pix looked like a collet. Maybe he is using the
terminology. . interchangeably.

BTW, Pete - do you plan to heat treat the ones you are going to make? If
so, how will you handle the "internal stress" problems alluded to by Harold?
Will you grind?

Bob Swinney



"Pete Keillor" wrote in message
...
On Tue, 31 Jan 2006 20:02:19 -0800, "Harold and Susan Vordos"
wrote:


"axolotl" wrote in message
...
The task is to make end mill holders for my "Eklind" vertical mill head,
that uses collets similar to a Bridgeport B3 (sort of a shrunk R8).

A sketch of a collet that would fit can be seen he

http://metalworking.com/DropBox/_1999_retired_files/UNKNOWN_collet.jpg

My material is 12L14 bar, about 4" long.
The lathe is a SB 9 Mod C., without a toolpost grinder.
I will be using a B3 collet as the template for the draw angle.

What order of operations will maintain concentricity as I drill, turn,
bore and ream?


Thanks,

Kevin Gallimore

snip good stuff
Cut your slots last, after you've
tapped the thread. Any changes at that point will be self correcting
when
the collet is in use. Deburr the slots well, naturally. Does this make
sense? Need more info?

Harold



Pete Keillor

The steel I would use in this application, if heat treatment were not
part of the job, is C1144 for preference, or 4140 heat treated and
stress relieved.

Both have a yield strength in excess of 100,000 PSI, and the C1144 is
also quite hard and reasonably wear resistant, while a pleasure to
machine.

I use C1144 also to machine crank shafts from the solid, but that's
another story.

Wolfgang

"Pete Keillor" wrote in message
...
On Tue, 31 Jan 2006 20:02:19 -0800, "Harold and Susan Vordos"
wrote:


"axolotl" wrote in message
...
The task is to make end mill holders for my "Eklind" vertical mill
head,
that uses collets similar to a Bridgeport B3 (sort of a shrunk R8).

A sketch of a collet that would fit can be seen he


http://metalworking.com/DropBox/_1999_retired_files/UNKNOWN_collet.jpg

My material is 12L14 bar, about 4" long.
The lathe is a SB 9 Mod C., without a toolpost grinder.
I will be using a B3 collet as the template for the draw angle.

What order of operations will maintain concentricity as I drill, turn,
bore and ream?


Thanks,

Kevin Gallimore

snip good stuff
Cut your slots last, after you've
tapped the thread. Any changes at that point will be self correcting
when
the collet is in use. Deburr the slots well, naturally. Does this
make
sense? Need more info?

Harold


Except he said end mill holder, so he won't need the slots. Substitute
drill and tap setscrew holes last. I've got the same job when I get
my M-head with B3 collets up and running. Also 5C end mill holders
for the TM.

Pete Keillor

Thanks, Pete. Nothing like having your head in a dark place, eh?

g

Harold

On Wed, 1 Feb 2006 07:05:18 -0600, "Robert Swinney"
wrote:

Pete sez:
" Except he said end mill holder, so he won't need the slots. Substitute
drill and tap setscrew holes last. I've got the same job when I get
my M-head with B3 collets up and running. Also 5C end mill holders
for the TM."

Yeah but, the drop box pix looked like a collet. Maybe he is using the
terminology. . interchangeably.

BTW, Pete - do you plan to heat treat the ones you are going to make? If
so, how will you handle the "internal stress" problems alluded to by Harold?
Will you grind?

Bob Swinney


snip

Right now, I don't plan on heat treating and grinding because I don't
have the equipment. Instead, I intend to make them out of a steel to
be determined, hopefully a good compromise between machinability and
toughness (suggestions welcomed, I already saw one on this thread). I
figure if I can make 'em once, I can make 'em again if need be.

If they don't hold up to my hobbyist use, then I'll have an excuse to
look into grinding. Of course, I've already been lusting after
grinders and a good electric furnace. But as a matter of a little
project discipline, I've suspended acquisition mode until I get what
I've got up and running.

Pete Keillor

On Wed, 1 Feb 2006 17:52:03 -0800, "Harold and Susan Vordos"
wrote:


"Pete Keillor" wrote in message
.. .
snip----

Right now, I don't plan on heat treating and grinding because I don't
have the equipment. Instead, I intend to make them out of a steel to
be determined, hopefully a good compromise between machinability and
toughness (suggestions welcomed, I already saw one on this thread). I
figure if I can make 'em once, I can make 'em again if need be.

That's a no-brainer. Stressproof.

Harold

Thanks, Harold.

Pete

Good move Pete! Pick a good steel, machine it carefully and it'll probably
hold up very well for the duty you will put it to. And think of all the
abrasive you'll be saving from getting in your machine. I think Harold is
right - when he says, "don't grind if you don't have to". The old timers
did pretty well with lapping and such.

Bob Swinneey
"Pete Keillor" wrote in message
...
On Wed, 1 Feb 2006 07:05:18 -0600, "Robert Swinney"
wrote:

Pete sez:
" Except he said end mill holder, so he won't need the slots. Substitute
drill and tap setscrew holes last. I've got the same job when I get
my M-head with B3 collets up and running. Also 5C end mill holders
for the TM."

Yeah but, the drop box pix looked like a collet. Maybe he is using the
terminology. . interchangeably.

BTW, Pete - do you plan to heat treat the ones you are going to make? If
so, how will you handle the "internal stress" problems alluded to by
Harold?
Will you grind?

Bob Swinney


snip

Right now, I don't plan on heat treating and grinding because I don't
have the equipment. Instead, I intend to make them out of a steel to
be determined, hopefully a good compromise between machinability and
toughness (suggestions welcomed, I already saw one on this thread). I
figure if I can make 'em once, I can make 'em again if need be.

If they don't hold up to my hobbyist use, then I'll have an excuse to
look into grinding. Of course, I've already been lusting after
grinders and a good electric furnace. But as a matter of a little
project discipline, I've suspended acquisition mode until I get what
I've got up and running.

Pete Keillor

"Pete Keillor" wrote in message
...
snip----

Right now, I don't plan on heat treating and grinding because I don't
have the equipment. Instead, I intend to make them out of a steel to
be determined, hopefully a good compromise between machinability and
toughness (suggestions welcomed, I already saw one on this thread). I
figure if I can make 'em once, I can make 'em again if need be.

That's a no-brainer. Stressproof.

Harold

"Pete Keillor" wrote in message
...
On Wed, 1 Feb 2006 17:52:03 -0800, "Harold and Susan Vordos"
wrote:


"Pete Keillor" wrote in message
.. .
snip----

Right now, I don't plan on heat treating and grinding because I don't
have the equipment. Instead, I intend to make them out of a steel to
be determined, hopefully a good compromise between machinability and
toughness (suggestions welcomed, I already saw one on this thread). I
figure if I can make 'em once, I can make 'em again if need be.

That's a no-brainer. Stressproof.

Harold

Thanks, Harold.

Pete

Welcome!
You'll love how it machines. It works better with HSS (positive rake with
chip breaker) than it does with carbide. Wonderful finishes and great chip
control.

Harold

Thank you gentlemen. I agree that 1144 is a better material for this
application. I am a small quantity user. I could not find drops of 1144,
and 12L14 bar ends are available on Ebay for a reasonable price. This is
my first experience with 12L14, and for me 1144 machines better. I'm
sure this says more about my lack of skill than the qualities of the metal.

Kevin Gallimore

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