Sch...I’ve freed up numerous Prentiss swivel jaws and here’s a few tips that might help. First off I’ll never hit the jaw towers. I always use blocks of wood and tap at the back. I’ll give it a good ten hits and then I’ll do the same from the other side. I’ll keep alternating until I can get some movement. If I can get the jaw to move 1/16 I know I’m going to win the battle. The most important thing is not to damage the jaw itself, slow and steady wins the race. Good luck, here’s a pic of a 22 like yours.
I let the PVC 22 sit for a few days, possibly giving PB Blaster time to work, then applied the Smitty method. Swivel jaw came free in about 3 minutes. 4lb hammer, block of 2x4, a little help from Desmond Stephens. As easy as anything I've done with a vise.
CHARLES WAUGH: Thanks for the pics of the American Scale swiveler. I love seeing the different designs the vise makers came up with.