This centerless grinder is about 15 years younger than myself.
The plant staff said that the drive belt needed replacing. I told them "I have only found one machine I couldn't make worse so let me at it." Staff said they had watched youtube videos and the transmission housing needed to be stripped down to reach the belt. Sometimes the old man just gets cranky and says "Step aside lads, I will do it my way." They walked away, trying not to step on their bottom lips.
After removing the motor it was found that the variable speed drive slave pulley had a severe case of arthritis.
The sliding half was given a hardy thrashing with a small sledge cushioned with blocks of wood. After 15 minutes of pounding, it was threatened with "if you don't come apart we will make a go-cart out of you." Sometimes with this old stuff you just have to use some not too gentle persuasion to make it move. A quick removal of caked-on sludge, two new O-rings and a bit of lube had the drive functioning again.