I purchased the bearings and chain/sprockets all from:
https://www.surpluscenter.com/item.a...ame=powerTrans. The same company another AZer recommended for bearings. It was very inexpensive. I think I bought one length of chain and split it up to fit my needs. I also enclosed the chain drive to keep dust off the lightly oiled chains. I attached a few pics. This was roughly patterned after the unit in C.Hightower book. I made it free standing with a shelf on the bottom. Never found a need for doors, as the room is clean and water based finish dries fast. The blower is a cheap harbor freight dust collector that I adapted with a plumbers rubber pipe sleeve. It moves plenty of air outside of my house when I am spraying. I shut if off after it tacks up as the finish is totally non toxic.