I have this in a 8 inch pulley , variable speed pulley assembly, tag on it reads model 609-100, it is new, has aluminum spindle and pulley which has very hard surface, weight is 10 lbs., shipping weight 12 lbs. ,center spindle inside hole .995 and 9 3/4 inch long, drive where keyway is 1.510 , keyway .375, groove 2.25 long, pulley is 1 1/8 wide at top of pulley  grove, spring loaded pulley should spread open 3/4 inch wider to make top pulley 1 7/8 wide , sells as is, I have a few of this set up if you need more of them, please check my other auctions