[captainclock1988]

Yes, I agree, its more or less a miniature rubberized pulley, where you have your groove track for your belt to ride in just like you do on the bigger pulley that drives the tuning capacitor.   

I've got some capacitors on order for this radio so then I can recap this radio and then it will work as good as new again, I even managed to properly repair the band switch which was broken on my radio because one of the rivets that held one of the pivot joints together for the band switch was broken and the previous owners of the radio attempted to repair it with a 4-40 screw and 2 nuts to hold it all together but the nuts kept coming lose which made the band switch have too much slop to it whenever you would change bands.