Post vises are difficult to accurately date because they were made by many manufacturers for many years. Best thing you can do is clean it up good and look for Identifying marks. I use a wire wheel on a 4-1/2" grinder for the job and it doesn't take that long. Faint markings can often be read when soapstone or chalk is rubbed into them. Best place to find Markings are the top / back of the moveable jaw and the mounting plate. That vise has been rode pretty hard and has lost it's meat ball and handle. I doubt that rear screw cover is stock and for sure the pulley converted to thrust washer isn't. Nothing that can't be fixed with some effort though. Ed.
