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?

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

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

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.

ok here is one

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.

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!

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.

Edited July 6, 200818 yr by ThomasPowers

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

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

I think that red paint may be the problem. The jaws are scrunching sideways so as not to have to see it.

I do believe it will be sand blasted shortly!

It looks to me like it is racked to the side at the pivot. You might be able to adjust some of the misalignment out with a new pivot bolt, but I kind of think that your vice could use a long visit with a torch to heat just above the pivot area (on the front jaw) and then a short visit from a large hammer to straighten things out. I normally avoid applying heat directly to the pivot because I have found that it is far too easy to strech out the pivot bolt hole when trying to straghten things out, but you will barely notice the kink if you true it up a 1/2 inch above the pivot. Don't forget to remove the screw to avoid any potential damage to this very hard to repair part when you attempt the straightening.

Edited July 7, 200818 yr by Jose Gomez
Forgot to warn him about the screw

when I put a straight edge on it its straight( the font jaw) I 'll put a square on the back jaw to see if the pivot is bent.

Thomas I tried a the bolt ...that didn't help .I took is all apart ; with just the bolt and two jaws it will line up, but it has a lot of play. I found that the inside of the pivot plates
were bumped out so I filed them flush...that amplified the problem as Jose noted (boys got a sharp eye). I think I can work a brass shim on one side and correct the problem. any way thats the plan at this time ...thanks a bunch for all the information

On Sunday, July 06, 2008 at 12:30 PM, Jose Gomez said:

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

 

Quietstorm, this is an old thread but are you saying " showing" that your post vise doesn't close properly?

from what I think I see in the picture it could be that the screw and box are from a different vise and longer or thicker then your vise should have. If that is the issue I'm betting it can be fixed a couple ways.