I think it is a wood-working vise because it has leather strips glued to the jaws for protection.
The jaws appear to be lag-bolted between the base block and the lower face-plate. There is also a square piece of leather on the center of the faceplace. For what??
Total base, including the plate, is 4 1/2' by 5'.
The jaws are almost 7' tall and are loose enough on the lag bolts to move to the inside or outside.
The screw is metal and the handle looks like aluminum.
Just wonder what sort of animal I have here. How old it might be, or anything else you might be able to share.
Here is a link that might be useful: