Re: [CAD_CAM_EDM_DRO] Thread size on ww collet

Joe,
WW collets are a very mixed bag. It depends on the brand.
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WW Collet threads:

40 tpi = 0.625mm pitch

The correct "American" thread for WW collet DRAWBARS** is, according to the
Levin catalogue, faxed to me two days ago:

Catalogue No 0031-01 Drawbar Tap Type WW 0.275-40tpi NS GH2
**Note this is for Drawbars NOT necessarily the correct spec for male threads
cut on collets etc.

I say this because it is known that the WW threads are originally an anglicized
version of the original 8mm European sizes..of which there are MANY..most of
which are interchangeable with WW collets, drawbars etc.

It is also known that, in order to facilitate this interchangeability..drawbar
threads are purposely cut to maximum sizes

Thus, if you have a drawbar tapped to the above spec..either .275-40 tpi H2 or
the equivalent metric size 6mm x .625mm you can use WW or 8mm collets in it from
all the following manufacturers..my sizes are taken from "the Model Engineers
Handbook" by ..Tubal Cain..the other guy..the REAL ONE as someone said!!

8mm collets from Adams, Boley, Boley-Leinen, Coronet, Derbyshire, Pultra and WW
are all threaded 0.268-40 and will all be a fairly sloppy fit in your
drawtube.
8mm collets from Wolf-Jahn are threaded 0.270-40 and will be a little tighter in
your WW drawtube

8mm collets from I.M.E. and LORCH are threaded 0.275-40 (6mm-.0625) and will be
a fairly snug fit in your drawbar.
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The above notes were from "Teenut".
I recently bought a bunch of WW's on Ebay and all of the above proved to be true.
Some are a good fit and some are sloppy. Also the body diameters vary from 0.311
to 0.315. The Sherline WW collet adapter for Starrett collets (0.312 dia)
will not accept the larger sizes.
RichD


joevicar3@... wrote:

>
> What is the thread size on a ww collet?
> Thanks joe V.
>