Model A front pulley?

[Tony G]

While sorting through my boxes of spare parts I found a pulley that fits perfectly on the crank but the center hole protrudes out a little more and its threaded internally. The internal threads indicate to me that you dont use the usual ratcheting nut for the A.The pulley diameter is a little smaller than the normal A pulley too. Can this be some part of an aftermarket add on kit? Im stumped.

 

[John LaVoy]

There was a two piece pulley made several years ago that screwed together, you still held it on the crankshaft with the nut. Perhaps that is what you have.