Right Ed. There all kinds of bearings in use. You certainly don't want axle grease in a computer hard drive bearing.Ed in Tampa wrote:I have bought bearing that came in small boxes. The bearing inside was wrapped in a wax paper sort of thing. I have at times had that wax paper covered with oil. These were sealed bearings and were used in slow rpm applications.
I don't know where the oil came from, left over from manufacturing or leaked out of the bearing.
Again very low rpm applications so I didn't see any real failures.
The bearings we used in computer I/O were shrink wrapped and I was told never to use one that wasn't sealed or was in an oily package. Never had any problems all were cleanly packaged. Although I did change a lot of bearings. These were all very small high speed bearings.
The F-22 generator rotor bearings are open cage and run at 22,000rpm. They are lubricated by the cooling oil that is sprayed into the sealed generator stator/rotor cavity that cools the generator. In all the years that I overhauled the F-22 generator I never had to replace one of those bearings.