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Joseph Gwinn Joseph Gwinn is offline
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Default Making Replacement vise jaws

In article ,
RBnDFW wrote:

On 11/24/2010 8:58 PM, Joseph Gwinn wrote:
In ,
wrote:

On 11/24/2010 3:22 PM, Joseph Gwinn wrote:
In ,
wrote:

My mill came with a 4" Palmgren vise. It's a bit light, and lacks
dovetails& gibs. It's basically a drillpress vise.

So I acquired a heavy old Victoria 4" milling vise. It looks fine save
for the jaws, which need replacing. Any chance of buying replacement
jaws for this old vise?

Assuming the answer is no, making jaws looks fairly simple.
I think I have some tool steel plates in about that size.
Is that the appropriate material?
Will my bandaw cut it?
Will regular drills work?

I made some flat (no teeth) jaws for my 3" Wilton Machinist vise out of
O1 Oil Hardening Steel, and it worked just fine. Ordinary saws, drills,
and mills work just fine, but don't stint on the black sulfur cutting
oil.

I plan to harden the jaws, but have not yet gotten around to it, and
they don't seem any the worse for it.

I have a bunch of spare parallels about the right size, figured I'd try
using two of those if that plate stuff I have is too narrow.

I'm not sure what those plates are actually. They are about 3"X12",
in thicknesses of approx 1/16 - 3/8". They were individually wrapped in
oilpaper. They are *very* hard steel. I'm not confident I can cut them.


Stop! You will *not* be able to cut them with ordinary drills, saws,
and end mills. You will instead destroy your cutting tools.

For the record, the parallels are probably something like W1, but
hardened. W1 is dirt cheap.

Life will be far easier if you buy some precision ground O1 flat stock
from MSC or the like, already in the correct size. Then all you need to
do is cut to length and drill and counterbore some holes.

O1 is a far stronger steel than W1, so even unhardened will be stronger
than W1. For small quantities, the cost differential isn't great. Buy
enough O1 so you can throw the first jaw away. It happens.

Hardening O1 is easy. Heat to orange-red with a torch, dunk in corn oil
(cheapest suitable oil, get from grocery store) in a metal container (so
no disaster if you drop the red hot workpiece). I hold the workpiece by
threading some heavy iron wire through the screw holes. Polish scale
off with wet wet-dry sandpaper, temper with torch by heating slowly
until it turns pale blue. After torch is removed, color will deepen to
dark or darker blue, which is the traditional spring temper.


The key is to make sure that the new jaws rest firmly in their pockets
in the vise, so the clamping force is transferred from jaws to frame
without undue concentration. In the Wilton, this required that one long
edge be beveled (so it wouldn't bottom on the inside radius of the
pocket) and the elimination of all burrs and irregularities.

I might have missed that, thanks

All this can be done with hand tools, but is a lot easier with a mill.
The hardest part is making the counterbores to accept the 1/4-20
Filister head screws that hold the jaws to the frame.


On machining counterbores, I found that it was best to do this in two
steps. First, rough the counterbore out. Then blow all the chips away,
liberally daub with black sulfur oil, and then make the final cut. This
procedure prevents the chips from scouring and thus mangling the
surfaces upon which the heads of the cap screws will rest.


I replaced the original screws with hex socket head machine screws so I
could change the jaws without taking the vise apart using a standard hex
key.

This one had SHCS already, so I'll go back with those. the fixed jaw had
been milled back over time until the heads of those two screws were all
but gone. Took a bit to coax them out.


I forgot to mention that it's a good idea to smear the threads liberally
with anti-seize compound.

It's also necessary to ensure that the screws do not control where the
jaws end up in the sockets in the frame - the jaws should be
loose. All the screws do is clamp the jaws in place, but not attempt to
locate the jaws.


I would just have at it. The worst that will happen is that you will
throw your first attempt or two away. I have one of those too. Nice
paperweight.


Joe, I believe you've got me covered.
I'll probably order some W1, and make a practice set first from some
good scrap material while I wait for the W1 to arrive
Much thanks.


Good luck. If the thick W1 section warps or cracks on quenching, you
can also oil quench W1. It won't get as hard, which isn't really a
problem for a vise jaw.

O1 machines fairly well, but the cutting forces are about double those
for W1.


Joe Gwinn

Joe Gwinn