My $9, much used, HF 4-1/2" angle grinder has a bad bearing. To replace it I need to remove the spur gear on the end of the motor shaft. The gear is threaded on, but has some sort of retainer, I think. It kind of looks like a key, but it's not: the shaft doesn't have a keyway & the shaft is threaded.
I hope I can fix it 'cause otherwise it's a perfectly good grinder & why should I spend $9 on another one? Although I haven't seen them for $9 in quite a while. $15 now, I think.
Bob