Subject: Collet Sizes

From: [email-masked] (John Bryant)
Date: Thu, 15 Sep 1994 19:31:30 GMT

Some time ago I came across a Hardinge collet chuck (of the kind in
which turning a rim draws in the chuck) at an auction, and was able to
buy it at a fairly modest price.  It fits my lathe (D1-3) and, as D1-3
backplates are relatively scarce and expensive, I thought it would be
worth it even if I wound up junking most of it and just using the back
end of it as the basis of a small faceplate.  What I really would like
to do, however, is to convert it to take 5C collets (as opposed to the
larger collets for which it was designed).

I've got the job pretty well planned out and don't see any major
problems.  It would help, however, if I could be sure of the thread
I'm dealing with.  I believe that the chuck was designed for 2J
collets: the outside diameter is 1.625 inches and the thread about the
same though it must obviously be at least a little (1/64?) less.  The
thread appears to be 18 TPI but I've yet to measure this properly.

Does anybody out there have the specification for 2J collets?  Or
does anybody know of any other collet type having a 1.625 inch O.D.?

                           Thanks in advance 

                             John Bryant ([email-masked])

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From: Charlie Mineau <[email-masked]>
Date: Sat, 17 Sep 94 16:18:58 -0500

>thread appears to be 18 TPI but I've yet to measure this properly.
 
Your correct the collet chuck you have uses a 2J Collet 1.611-18 RH.
It has a back bearing diameter of 1.625 overall length of 3.250.
These collets have a part # 1539 1-3/8 Max round andcan be purchased
from Hardinge Brothers 1-800-843-8801. If you do make an adaptor to 5C
with less than .001 runout I'll buy one from you, for a reasonable price.
Hope this helps.
Charlie