Bronco did a great right up on how to convert to dual bearing rollers.  Its worth doing, and has the pics you need.
http://www.blasterforum.com/threads/converting-to-a-dual-bearing-chain-roller.55355/
				
			http://www.blasterforum.com/threads/converting-to-a-dual-bearing-chain-roller.55355/
				
		


