Post vise jaws

[Aframe]

I recently picked up an iron city post vise and the jaws don’t close flush. There is a gap in both planes. Do you think it would be possible to heat and bend it into place or am I better off milking it to close flush?

[JHCC]

Pictures?

Post vise jaws are only supposed to touch at the top when they’re completely closed. 

[Aframe]

I’ll try to post some more photos shortly. Thanks for any advice

[JHCC]

Ah, yes; clearly the result of overtightening. Over the years, the legs have bowed inward slightly, creating the reverse of the desired contact.

I recently straightened a twist in my vise's moveable jaw by heating the front leg, putting a bit of steel in the too-close side of the opening, and using the power of the screw to twist the front leg in the opposite direction of the twist. It worked exceptionally well, although I think it bowed the front leg in slightly, closing the gap at the bottom of the jaws just a bit more than I'd like. I've considered repeating the experiment, but using a block between the legs as a fulcrum to put bow the front leg back in.

The "H" represents the spot to be heated, with the fulcrum block shown just below it. It occurs to me, however, that putting the block right at the heated spot would focus the bending moment from the screw at that one spot, making it slightly easier to bend.

To be clear: I have not tried this myself, so if you want to give this a shot, then (a) proceed at your own risk, and (b) let me know how it works!

(Addendum: if you don't remove the vise spring before heating, it will probably deform and need to be reshaped. Don't ask me how I know this.)

[Aframe]

That’s actually a great idea. I should take a closer look at the legs to see if that’s where the gap originated. Thank you 

[ThomasPowers]

If your hydraulic press is of a size you may be able to adjust it cold.  I don't have a Hydraulic press and so I have to work hot. 

I don't see where placing a block in the jaws and tightening the screw could close them correctly. I think it could only make them worse for this case.  It's a great idea for resolving a twist though---followed up by making a set of spacers to be used on the other side of the vice jaws when hunkering down on the handle to prevent twists from forming.     ==||=====   bad    ==||===||=  good

[JHCC]

1 minute ago, ThomasPowers said:

I don't see where placing a block in the jaws and tightening the screw could close them correctly.

That's why I'm suggesting placing a block between the legs and using the screw to pull the moving jaw in.

If the pivot bolt is the fulcrum, the block is the effort, and the screw is the load, then block-in-the-jaws makes a class 2 lever that will make the leg more concave (bend it outwards). However, block-between-the-legs makes a class 3 lever that will straighten the leg (bend it inwards).

[ThomasPowers]

Ah I missed that.  Rough day yesterday and I'm paying my body off in installments!  (Went to PT for my hip issues and then went home and climbed the ladder multiple times to get the swamp cooler repaired. OTOH we had to use a quilt last night and the swamp cooler is in the far end of the house from our bedroom!)

[Irondragon Forge ClayWorks]

I have one of those HF bench top presses and it has straightened & bent some hefty stock cold. The biggest piece I can remember was a draw bar off of my old Ferguson tractor (about the dimensions of a 2X4) no problem.