Jules Richardson wrote: Nah, all bearings are standard. Gordon. No, not on disk drives. Some are the standard size, but lubricants, especially grease, are unique to disk drives. The grease had a bad habit of out gassing hydrocarbons, which eventually cover the head and media surfaces. Disk drive lubrication became such a science that eventually only one or two companies would meet the standards. Bearings also had a bad habit of allowing particles to pass through them and cause head crashes as flying heights came down. Bearings then moved to labyrinth seals. They look like standard bearings, but they are not. Billy