Need help with term/ name of a tool "impact cap"

Decades ago my Dad had 2-3 of what I am thinking, different threads/ sizes. We are thinking of a tapered shaft flywheel or similar to the old Mopar/Ford/ IHC / Jeep tapered axles. On stuff like some lawn mower engines which have no puller tappings........

THIS IS A large extended "nut" with a closed end. You thread it onto the crank or shaft threads, and it gives you a "safe" face to whack and knock the flywheel loose. I can't find anything, don't know what they were called