I believe someone recently mentioned that their welder was an "Old Sears" model.
A friend of mine has an old Craftsman that seems to work well on the receptacles that are not loose. Someone backed into it and messed up several of the sockets you plug the leads into. However, it works well on the ones that you can plug into.
Model 113.20241 Made by Simpson-Sears, LTD. but wearing the Craftsman name. I just tried to locate the parts for it and they are listed along with a diagram at sears.com -- BUT UNAVAILABLE!