FV: to help your search try Cole in the vise threads. it's not a highly sought after and not quite sure how to use it, but I'm sure it has it's use. yours is attached to a nice chunk of steel too.
I'm pretty sure they were used mostly in Blacksmith and old shops to beat on, but i found this picture and saved it of one restored with it holding an old school drill press that has a pretty nice look to it.
by the way what area do you live and do you pick up big chunks of steel like this often or was this one your grand dad's?