Faulty: your cute little Athol looks like it's had a modification to the base? can you take and post up a few more pictures of it that might be easier to see and some pics of the underside of the base? I saw you posted pictures of some nice Craftsman block grinders so i'm guessing you have the ability.
some of these little vises are worth a lot so even one that has had a rough life and some modifications might be worth saving cause it does have the cool look.
also instead of starting threads that are hard to find as they get their questions answered if you could post up pictures and questions over on the Vise Repair 101 thread you might get more help or it will help others later cause that thread can be found easier.
here's the link:
https://www.garagejournal.com/forum/showthread.php?t=252830
if you'd like to take your Athol apart it should just unscrew apart. then if you'd like to take the screw out of the dynamic jaw using a pipe with a notch in it to push the spring/washer back while you pull the cotter pin might help you if that little vise is the same as it's bigger brothers.
in case you didn't know Starrett owned Athol and eventually Starrett put their own name on their vises.
also good luck!!