kind of interesting that Timken was big on this. they made roller bearings. other than the wheels for the landing gear i can't thing of too many other things on the ac would be roller bearings. i have never run into those doing engine, transmission, etc work. roller bearing tend to need to be "loaded". while i was in the auto parts biz that was the main and pretty much only reason i sold rollers...maybe flyboyj has seen them elsewhere.