On 04/11/17 17:53, Daniel Koller wrote:
...the problem comes when it's time to remove that stub and face the end. Then I have no place to hold the piece without marring it. If I use one of my MT3 collet chucks, then if the piece is as little as ~10 mils less than the nominal diameter of the chuck, it spins. The MT3 chucks I am using have very little range. And the other concern is I am tightening them up against the inside of my lathe spindle directly. I am concerned that over time I may wear it down. So I think I will keep those for holding end mills and get an E32 system for holding parts. Thanks folks!

Dan


On Friday, November 3, 2017 at 1:00:06 PM UTC-4, Jim Wilkins wrote:
"Daniel Koller" wrote in message
...
Hi Folks,

If I were to buy one of these sets of Chinese made ER32 collets on
e-bay
(https://www.ebay.com/itm/19pcs-ER32-...100005.m185 1)

...what is the range of each collet? With increments of 1/16" can I
hold any size rod?

If I have 3/16" and 1/4" for example, do I need 7/32"?

I see that the 20 piece set that I linked, has incrememts of 1mm.
1/16" is 1.6mm so it seems to me I would have gaps if I only got 1/16"
increments.

Right now I am using a MT3 collet set, but I am finding it pretty
limited. It holds nominal stock sizes just fine, but if I take a few
mils off to clean up the OD before chucking it, the rod slips.

Thanks for the advice!

Dan

p.s. Intended use is on a 1952 Logan 10" (Wards) lathe. MT3 taper in
the head, MT2 in the tailstock.

=============================

In general I've found that only precision ground drill rod that fits
my 5C collets deserves them, a chuck is fine for rougher stock.

If the piece will need to be removed to check fit and replaced on the
lathe it's easy enough to turn a stub on one end to collet size.
-jsw

One problem I've encountered with ER collets is gripping short lengths
which they don't seem to like, I presume due to the internal collet
diameter being partly unsupported by the part. By short lengths I'm
referring to items maybe less than half the collet length. I've dealt
with it recently by adding a suitably size plug in the rear of the
collet and that seemed to sort the problem.