"xray" wrote in message
...
On Fri, 05 May 2006 23:41:53 -0700, xray
wrote:


I have a Jacobs 14N 1/2" chuck for the tailstock of my lathe. The MT2
arbor it is mounted on has spun in some past life and is a bit munged
up.

I ordered a new JT3 to MT2 arbor for it, but now I find I can't budge
the existing arbor out of the chuck. It's not rusty. I've soaked it
penetrating oil for about a day. I tried heating it with a torch and
then later by baking it in the oven. Quickly cooled the arbor with a wet
sponge while the chuck was still several hundred degrees from the oven.
I've succeded in slightly bending a Starrett center punch trying to
pound the arbor through the center hole in the chuck.

Any tips on things I could try to break up this long-term relationship?

Thanks for all the ideas. Maybe some of the things like Bob's idea of
side pressure and my application of several heat(400f)/cool cycles may
have helped break it loose.

The final solution was brute force. I drilled the hole through the
center of the chuck a little bigger so I could fit a bigger punch to the
arbor and then used a big hammer.

There was no galling inside the chuck mount taper, so it was just simple
metal to metal contact working better than I expected.

A long battle to finish exactly the way I started.

Glad you got it off okay. Another method is to fit a sturdy pipe, a little
longer than the arbor, loosely around the arbor. Then, with the chuck at the
top, slam the pipe end as hard as you can against a solid steel surface. The
inertia of the arbor will often pull it out.
Don Young