I'm starting to use my new (33 years old) Rockwell 46-451 lathe and have been hearing the belts sqeaking alot. Everything is working just fine (reeves drive works well) but I want to replace the belts. I noticed tonight that one of them still has the Rockwell part number on it from when they were new, so these are the original belts that came on this lathe back in July of 1977 when this lathe was built. The manual I have says that they are 65 OC and 37 OC. I'm not sure what OC stands for??? I'm assumming that the belts are 65 inches long and 37 inches long. Would I be guessing right here?