5C collets - sizing issue
 

I'm having difficulty locating 5c collets specific to what I'm trying to do.

I have 2 different sizes of square brass stock. The first is 11.85 mm square (.467 in) the second is 5.96mm square (.2345 in) which (if I'm right equates to 15/32 and 15/64 respectively (can you tell I only do metric? :-) )

I can't find collets in these sizes - or should I be trying to get metric collets? Since the metal was purchased in the US, I think I should be trying to get English sizes.

My other collet is for brass hex stock - 4.98 mm across flats (0.196 in) which I think equates to 3/16. I have managed to find hex collets of that size so I think I'm ok there.

Any help appreciated!

Sprydle writes:

I can't find collets in these sizes - or should I be trying to get
metric collets?

Can you broach those square holes into machinable ("emergency") collets?

Hardinge makes square fractional 3/64 to 3/4 by 1/64 increments
1-800-843-8801
Jim
"Sprydle" wrote in message
...

I'm having difficulty locating 5c collets specific to what I'm trying to
do.

I have 2 different sizes of square brass stock. The first is 11.85 mm
square (.467 in) the second is 5.96mm square (.2345 in) which (if I'm
right equates to 15/32 and 15/64 respectively (can you tell I only do
metric? :-) )

I can't find collets in these sizes - or should I be trying to get
metric collets? Since the metal was purchased in the US, I think I
should be trying to get English sizes.

My other collet is for brass hex stock - 4.98 mm across flats (0.196
in) which I think equates to 3/16. I have managed to find hex collets
of that size so I think I'm ok there.

Any help appreciated!


--
Sprydle

"Sprydle" wrote in message
...
snip-----.

My other collet is for brass hex stock - 4.98 mm across flats (0.196
in) which I think equates to 3/16. I have managed to find hex collets
of that size so I think I'm ok there.

Not really. 3/16" is .1875", so the collet would be too small to grip the
stock properly. When you open up a collet that much to grip oversized
stock, it grips at the rear only, often indenting the material because the
gripping surfaces are no longer parallel. It could prove to be a problem
in brass. The other inherent problem is that the material won't
necessarily end up parallel to the spindle due to the very narrow area of
contact. It may not be self aligning. You should try for a collet that is
within +/- .001" of material size if your project is critical.

Harold

In article , Harold and Susan Vordos says...


"Sprydle" wrote in message
...
snip-----.

My other collet is for brass hex stock - 4.98 mm across flats (0.196
in) which I think equates to 3/16. I have managed to find hex collets
of that size so I think I'm ok there.

Not really. 3/16" is .1875", so the collet would be too small to grip the
stock properly. When you open up a collet that much to grip oversized
stock, it grips at the rear only, often indenting the material because the
gripping surfaces are no longer parallel. It could prove to be a problem
in brass. The other inherent problem is that the material won't
necessarily end up parallel to the spindle due to the very narrow area of
contact. It may not be self aligning. You should try for a collet that is
within +/- .001" of material size if your project is critical.

The best way to make specials like this is to wire EDM a new undersized
collet. If only for a few parts, a soft steel collet can be used, or
a regular 1/16 or whatnot collet can be used to start.

Any shape can be done this way.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
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Try contacting Lyndex. They make a wide variety of 5c collets and will
probably have a 6mm and 12mm square, and the 5mm hex.

http://www.lyndex.com/prod_standard.asp?type=r85c3j

Sprydle wrote:
I'm having difficulty locating 5c collets specific to what I'm trying to
do.

I have 2 different sizes of square brass stock. The first is 11.85 mm
square (.467 in) the second is 5.96mm square (.2345 in) which (if I'm
right equates to 15/32 and 15/64 respectively (can you tell I only do
metric? :-) )

I can't find collets in these sizes - or should I be trying to get
metric collets? Since the metal was purchased in the US, I think I
should be trying to get English sizes.

My other collet is for brass hex stock - 4.98 mm across flats (0.196
in) which I think equates to 3/16. I have managed to find hex collets
of that size so I think I'm ok there.

Any help appreciated!

They are also available from Hardinge
http://hardingetooling.com/PartSpec....10010037060000
http://hardingetooling.com/PartSpec....10010037120000
http://hardingetooling.com/PartSpec....10010027050000

$35.75 each according to the web site.
available in .1mm increments and .001" in the round collets

Sprydle wrote:

I'm having difficulty locating 5c collets specific to what I'm trying to
do.

I have 2 different sizes of square brass stock. The first is 11.85 mm
square (.467 in) the second is 5.96mm square (.2345 in) which (if I'm
right equates to 15/32 and 15/64 respectively (can you tell I only do
metric? :-) )

I can't find collets in these sizes - or should I be trying to get
metric collets? Since the metal was purchased in the US, I think I
should be trying to get English sizes.

My other collet is for brass hex stock - 4.98 mm across flats (0.196
in) which I think equates to 3/16. I have managed to find hex collets
of that size so I think I'm ok there.

Any help appreciated!

In article ,
jim rozen wrote:
In article , Harold and Susan Vordos says...


"Sprydle" wrote in message
...
snip-----.

My other collet is for brass hex stock - 4.98 mm across flats (0.196
in) which I think equates to 3/16. I have managed to find hex collets
of that size so I think I'm ok there.

Not really. 3/16" is .1875", so the collet would be too small to grip the
stock properly. When you open up a collet that much to grip oversized
stock, it grips at the rear only, often indenting the material because the
gripping surfaces are no longer parallel. It could prove to be a problem
in brass. The other inherent problem is that the material won't
necessarily end up parallel to the spindle due to the very narrow area of
contact. It may not be self aligning. You should try for a collet that is
within +/- .001" of material size if your project is critical.

The best way to make specials like this is to wire EDM a new undersized
collet. If only for a few parts, a soft steel collet can be used, or
a regular 1/16 or whatnot collet can be used to start.

Any shape can be done this way.

Except that a square collet should have four slots, instead of
the three common to either round or hex collet (or to the "emergency"
ones which I have seen).

Hardinge is expensive, but I think the proper route for you this
time.

Good Luck,
DoN.
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