I could be wrong but my research has indicated the Mason did not manufacter sewing machines he was a dealer so his machines are badged from many companies. You need to identify the maker of your machine and go from there in finding slide plate. I could be wrong and I am sure people on the board can give more info than I can. If I am right it may not be that hard to find a slide plate. Ismacs has good info on this also.( ismacs.net.) Nice machine you have.