Check vise and/or jaws?
 

Hello all,

I finished squaring the block for my latest part, set up a stop, found
0,0 and clamped the evolving part in the vise when I remembered that I
should check the alignment of the vise. There was no reason to expect
misalignment, but one never knows, and all the more so given that I
recently shimmed the column.

The vise wasn't just in line, it was as close to dead nuts as I've seen.
Ok, it _could_ have moved favorably, but, I think something else is at
work.

Having the block in the vise, I indicated on the block, which I had
clamped with 1.5 inches front to back on the vise. Normally, I stand a
wide parallel in the vise such that it stands above the jaws enough to
give the indicator a nice surface. In that orientation, the vise is
squeezing a thin plate that would be "easy" to bend. A 1.5 inch deep
beam, even Al, is going to be much more ridgid in bending.

Indicating off of a parallel, I began to suspect there was a "bump" in
the middle/right the jaws, and have been meaning to dig into it and ask
some questions. Now that I've seen how steady the indicator reading can
be across the vise, I put the feed lever in neutral and started typing :)

The vise is a Kurt clone (H&H). Is there something simple that could be
wrong? Some junk under one of the jaws comes to mind; my hunch is that
you will have me start with removing the jaws and cleaning. What should
I do to find and hopefully fix it? Or, is it unrealistic to expect a
on-edge parallel to be flat when clamped in the vise? If that's the
problem, should I make another "deep" block to use for aligning the
vise? What material would be best?

Bill

Check vise and/or jaws?
 

Just indicate on the fixed jaw of the vise.

Bob Swinney
"Bill Schwab" wrote in message
ink.net...
Hello all,

I finished squaring the block for my latest part, set up a stop, found 0,0
and clamped the evolving part in the vise when I remembered that I should
check the alignment of the vise. There was no reason to expect
misalignment, but one never knows, and all the more so given that I
recently shimmed the column.

The vise wasn't just in line, it was as close to dead nuts as I've seen.
Ok, it _could_ have moved favorably, but, I think something else is at
work.

Having the block in the vise, I indicated on the block, which I had
clamped with 1.5 inches front to back on the vise. Normally, I stand a
wide parallel in the vise such that it stands above the jaws enough to
give the indicator a nice surface. In that orientation, the vise is
squeezing a thin plate that would be "easy" to bend. A 1.5 inch deep
beam, even Al, is going to be much more ridgid in bending.

Indicating off of a parallel, I began to suspect there was a "bump" in the
middle/right the jaws, and have been meaning to dig into it and ask some
questions. Now that I've seen how steady the indicator reading can be
across the vise, I put the feed lever in neutral and started typing :)

The vise is a Kurt clone (H&H). Is there something simple that could be
wrong? Some junk under one of the jaws comes to mind; my hunch is that
you will have me start with removing the jaws and cleaning. What should I
do to find and hopefully fix it? Or, is it unrealistic to expect a
on-edge parallel to be flat when clamped in the vise? If that's the
problem, should I make another "deep" block to use for aligning the vise?
What material would be best?

Bill

Check vise and/or jaws?
 

Bob,

Just indicate on the fixed jaw of the vise.

I have a good opportunity to try that, because I did some more work on
the collet chuck box and the vise was in the way. I think I tried the
fixed jaw and went to the parallels hoping for better results, in part
on the theory that clamping the vise makes the conditions as close as
possible to having a part in the vise.

I'll give it a try and report back. Thanks!

Bill