I have 3 sets of what appear to be 6" steel vise jaws. They are used and I think they came off a Kurt but don't know for certain. Check your centers. 2 different sizes. 1 set of 1 5/8"x6" and 2 sets of 2"x6". I think the centers are 3 7/8"? could be 3 3/4". Seem to be in good condition. Looks to have had some machine work done to the upper for jigging. Could be wrong. Could have just been a careless machinist. Either way, could be yours.