I need help. I have an older NH 472 hay-bine with the slip clutch on the gear box. I thought I had everything ready to cut hay in the morning, new sickle blades and all. I was hooking up late this evening and ran it a minute an noticed the big pulley that the drive belt is on was wobbling. I rotated the rollers and saw where a set screw on this pulley ( at the slip-clutch) was missing. I need to know if the set screw rests in a hole in the shaft or is just a set screw that tightens down on the shaft. I really need to start cutting tomorrow so any help is appreciated. Sorry for long post but I need help.