Hello Jcippon2:
A picture would help alot on seeing what you need. The lenghth of the screw would help also. The screw if the main failure piece on many vices so spare screws are hard to come by. If someone has a screw out of a vise with a broken jaw you might get lucky.
I just bought another vise. A Prentiss that weighs about 120 pounds. I got it from a retired fellow who has quit his mower repair business. $40 if you must know. The question is about the back jaw. There is a pin that holds the back jaw in alignment and it can be turned to accomodate odd shaped...