Hi all,

At a recent watchmaker's fair I bought a small vice. Old, in bad shape, but
better than anything I've got at the moment. The thing actually cracked in
half somewhere in its lifetime and was welded back together by someone with
a very big welding machine. The problem was that the jaws were not parallel
properly after that; there was a .7 mm gap on one side.

I've annealed the jaws and filed and sanded them back into shape. They close
well now, and are beautifully straight, smooth and polished, just as I
wanted.

My question: how can I best re-harden them? The jaws are only 6 cm wide, but
I'm only used to working with tiny pieces of steel to make watch components
or small tools. Can I just heat to cherry red and quench in oil? And then
temper by re-polishing and heating to some colour (blue, for example)?

I only have a torch, no kiln or something like that.

Cheers!

Rob

"Rob Kramer" wrote in message
. ..
Hi all,

At a recent watchmaker's fair I bought a small vice. Old, in bad shape,
but
better than anything I've got at the moment. The thing actually cracked in
half somewhere in its lifetime and was welded back together by someone
with
a very big welding machine. The problem was that the jaws were not
parallel
properly after that; there was a .7 mm gap on one side.

I've annealed the jaws and filed and sanded them back into shape. They
close
well now, and are beautifully straight, smooth and polished, just as I
wanted.

My question: how can I best re-harden them? The jaws are only 6 cm wide,
but
I'm only used to working with tiny pieces of steel to make watch
components
or small tools. Can I just heat to cherry red and quench in oil? And then
temper by re-polishing and heating to some colour (blue, for example)?

I only have a torch, no kiln or something like that.

Cheers!

Rob


Assuming the material is medium carbon steel or better, you can heat the
jaws until they are no longer magnetic, then quench. You risk cracking
them if you quench too quickly, so oil may be the better choice. Once
quenched, do as you suggested and draw back the hardness ever so slightly.

When you quench, it's important that you insert the jaws in the quenching
medium such that one side does not cool faster than the other, otherwise
you'll bow the pieces and you'll not be any better off than you were before.
Inserting them straight in, from one end, is likely the best choice.

The best scenario, judging from your description of the repaired broken
body, would have been to make the corrections on the body of the vise
instead of the jaws, which could then remain parallel and could be easily
resurfaced without effort, using a surface grinder. Hand working the jaws
may still prove to have been a bad choice.

Even with proper quenching, you may find that the jaws don't remain flat,
and will need to be worked once again.

Luck with the project! How about a report after you've finished?

Harold

Rob Kramer wrote:
....
My question: how can I best re-harden them? ...

Do you really want them hard? Why? Bob

"Bob Engelhardt" wrote in message
...
Rob Kramer wrote:
...
My question: how can I best re-harden them? ...

Do you really want them hard? Why? Bob

Jaws for holding finished pieces are best if they're hardened. While I've
not done a hardness check of mine (a Kurt), I would assume they run in the
mid 50Rc range. That avoids dinging the jaws with chips or other objects,
and transferring the dings to the next part installed. Hardening the jaws
is a good idea.

Harold

"Harold and Susan Vordos" wrote in message
news

"Bob Engelhardt" wrote in message
...
Rob Kramer wrote:
...
My question: how can I best re-harden them? ...

Do you really want them hard? Why? Bob

Jaws for holding finished pieces are best if they're hardened. While I've
not done a hardness check of mine (a Kurt), I would assume they run in the
mid 50Rc range. That avoids dinging the jaws with chips or other
objects, and transferring the dings to the next part installed.
Hardening the jaws is a good idea.

I like the replaceable jaws on my big vises. If I had a vise with soft jaws
and wanted hard ones, I'd drill and tap them for replaceable jaws, which I
could easily make as hard as I want.

--
Ed Huntress

Hi Harold,

Harold and Susan Vordos wrote:
Assuming the material is medium carbon steel or better, you can heat the
jaws until they are no longer magnetic, then quench. You risk cracking
them if you quench too quickly, so oil may be the better choice. Once
quenched, do as you suggested and draw back the hardness ever so slightly.

Thanks, also to the other posters. This is exactly what I did, and then drew
the temper to brownish. Seems to have worked quite well..

The best scenario, judging from your description of the repaired broken
body, would have been to make the corrections on the body of the vise
instead of the jaws, which could then remain parallel and could be easily
resurfaced without effort, using a surface grinder. Hand working the
jaws may still prove to have been a bad choice.

Yes, possibly.. But I thought it would be hard to file the vice body without
introducing some rounding of the flat behind the jaws. The way the jaws
slot into the body means I can only file the body in one direction, i.e.
sideways, and can't correct any rounding by filing vertically or by
draw-filing. (I hope this is a comprehensible description)

Cheers!

Rob

"Rob Kramer" wrote in message
...
Hi Harold,

Harold and Susan Vordos wrote:
Assuming the material is medium carbon steel or better, you can heat the
jaws until they are no longer magnetic, then quench. You risk cracking
them if you quench too quickly, so oil may be the better choice. Once
quenched, do as you suggested and draw back the hardness ever so
slightly.

Thanks, also to the other posters. This is exactly what I did, and then
drew
the temper to brownish. Seems to have worked quite well..

The best scenario, judging from your description of the repaired broken
body, would have been to make the corrections on the body of the vise
instead of the jaws, which could then remain parallel and could be easily
resurfaced without effort, using a surface grinder. Hand working the
jaws may still prove to have been a bad choice.

Yes, possibly.. But I thought it would be hard to file the vice body
without
introducing some rounding of the flat behind the jaws. The way the jaws
slot into the body means I can only file the body in one direction, i.e.
sideways, and can't correct any rounding by filing vertically or by
draw-filing. (I hope this is a comprehensible description)

Cheers!

Rob

Sounds like it turned out quite well, Rob. Congrats!

I understand about your choice in working the jaws instead of the body.
There are times when one does what works best. The thing that really
matters is that it now serves your purpose.

Harold