I added some other photos. It does look cast and machined. There is an internal plate and four adjustment screws on one side. Being so big and heavy I’m assuming that this had been a commercial quality woodworking bench vise.
Doe anyone know the manufacturer of this old 75lb woodworking bench mounted vise?
It has 13 inch jaws and can handle a 15 inch wide board. This vise is at least 55 to 60 years old. I couldn’t find any model number or manufacturer designation anywhere on the vise.