Post vice jaws don't close correctly

[jimbob]

I picked up a small post vice. After cleaning it up the jaws don't line up ...one side is 3/8 to the right of the other. with the screw in all the way the nut does not move.I throught it was the slot on the back jaw... the guide on the nut is worn on the front but the back seems ok...do I need to weld up the guide or build up the slot to make the jaws meet with out and overhang?

[Jose Gomez]

If you can post a few pictures it might help us to figure out how to best repair the vice.

[jimbob]

Originally Posted by Jose Gomez

If you can post a few pictures it might help us to figure out how to best repair the vice.

I'll see what I can do

[HWooldridge]

A lot of times you can grab the movable jaw and lean on it hard to line them up. You might also try swapping the pivot bolt 180 degrees from its current position (whatever that may be). They will wear more on one side over the years and cause the jaws to start slipping out of alignment. Last but not least, you can heat the pivot and frame in the forge and pull them into alignment.

[jimbob]

ok here is one

[djhammerd]

Take out the screw and see if you can move the jaws side to side. If so, do whatever is necessary to tighten that up a bit. Sometimes it's just tightening a bolt, sometimes it's tightening a rivet, or working to force the stationary sides together. The jaws should line up fairly well. If not, do as Hollis advised.

[jayco]

Jimbob, my post vise does something similar. The tab on the nut and the slot in the post are both worn. When the nut gets out of proper position( which it does once in a while), the jaws either won't go totally together or close mismatched like yours.

Hope you come up with an easy fix........I'd like to fix mine too!

[ThomasPowers]

It is *not* the job of the screw box and screw to align the jaws! They only serve to draw them together.

The alignment is done by the pivot joint at the base of the moving leg. That joint can be loosened by wear, (when was the last time you oiled it?) or abuse, (note that the moving leg may have been bent as well as the side plates being shifted or canted.

Simple repairs include changing out the bolt it piviots on, shimming between one side of the leg and the side plates, (or both if its quite loose).

More involved ones may include heating the side plates and closing up the space with the jaws clamped in correct alignment. Or heating the shaft of the moving leg and adjusting it so the jaws meet up correctly. Note that old post vises may be real wrought iron and if so profit from working the metal quite hot indeed! While malleable iron postvises would best be worked cold.

I had one large abused vise that was out of whack vertically where I took off the moving leg and heat shrunk and bradded in a slug in the original pivot hole, dressed the faces and redrilled the pivot hole down a bit so the jaws would align better. It's been close to 10 years and the "no weld" fix shows no sign of letting go.

[irnsrgn]

pictures of the whole vise top to bottom from the side and from the front would be beneficial in diagnosing the problem.

[jimbob]

more pictures. should I take the screw out and show the guide on the nut and the slot on the back jaw?