Is it worth 50? Well it is old, probably approaching 100 years old. How solid is it, how chewed up are the jaws? Wear on the screw? What does it weigh, looks pretty hefty, compare it to something new for $50, I think this antique would come out ahead, unless badly worn. And, what kind of work do you do, what is your primary use for it? I'd probably go $25 or 30 myself.