I have an old grinder. It is a Dunlap sold by Sears, I'm guessing in the 60s
or 70s. It is essentially a 1/3 horse electric motor with a 1/2 shaft
sticking out each end. Attached to each shaft is an attachment that is
female 1/2 inch on one end, such that it slides over the motor shaft and is
held in place with a set screw. The other end is a threaded 1/2 stud with
nut that you slide a grinding wheel (or whatever) on it and secure with nut.
Any wheel or brush or whatever with a 1/2 hole will fit on this.

I need one of these attachments. I've been to hardware and auto part stores,
and no one that I've found so far has any clue where I can find one of
these. Does anyone have any idea where I can find such an attachment?