Replacing a pulley/arbor key

no. a key is supposed to fit in easily. it’s just there to transfer rotational force to the pulley from the arbor, it’s not supposed to tighten the pulley and hold it in from falling out.

Edded: actually, you usually need to pay attention to the key when you take the pulley out so as not to lose it.

sounds like the key is oversized. I’d try to find a properly fitted key. or machine/file/sand the key down for a perfect fit – just don’t over do it. it does need to fit in easily, but not loosely.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

linesoflux: No….the keyway is not supposed to fit that tight that you have to heat it….It does need to be snug enough so as not to fall out, or vibrate loose.. If it’s a little big, then put it in your metal vice (if you have one), and file it down a little with a bastard file, or a small file,(whatever). If no vice, just hold in between your thumb and forefinger and file it….. not too much and check it often for fit….Been there and done that….

-- My grandpa used to say: "Y'all come back when you can....come after dinner, and leave before supper.."

Thanks for the quick responses. It seemed strange to me that it would be that tight. It also seemed odd that the old one (20 years) and the new one (weeks old) exhibited the same problem. Thats what made me think that it needed to heated or press fit somehow. Couldn’t imagine why it would need to be that tight since the set screw should suffice to hold it down…