5C collets - sizing issue

I'm having difficulty locating 5c collets specific to what I'm trying t


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

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

My other collet is for brass hex stock - 4.98 mm across flats (0.19 in) which I think equates to 3/16. I have managed to find hex collet of that size so I think I'm ok there.

Any help appreciated

-- Sprydle

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

Reply to
Richard J Kinch

Hardinge makes square fractional 3/64 to 3/4 by 1/64 increments

Reply to
Jim Sehr

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.


Reply to
Harold and Susan Vordos

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.


Reply to
jim rozen

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.

Reply to
DoN. Nichols

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