I made mine but TSC Tractor supply or any electric motor shop carry them thin Tractor supply you get a package of 2.

http://www.amazon.com/b?node=16411911

http://www.tractorsupply.com/en/store/countylinereg%3B-set-collar-1-2-in-dia-pack-of-2

http://www.fastenal.com/web/products/pow...08501%20Collars,%20Couplings%209and%20Components"%7C~%20~%7Ccategoryl3:"603515%20Shaft%20Collars"%7C~

I would tap in an extra locking set screw and red lock tight them after positioning.