I have a Skill belt sander model 594 type 3. The main plastic drive gear broke. This unit is at least 35yrs old and Skill no longer has parts. I have called numerous other sources but to no help. does anyone know where I might find one of these parts or something that might replace it. It is very nice small sander and would like to keep it. I have used others that I don't like as much. Any help will be appreciated.