Q: What are sleeve bearings usually made of, stainless steel, bronze, aluminum, or cast iron?

A: Sleeve bearings can be made from bronze, steel or stainless steel. Brass bearings and plastic sleeve bearings are also manufactured for certain applications. A common type of sleeve bearing that works well in applications requiring constant lubrication is bronze sleeve bearings, which sometimes contain lubricant plugs (PTFE or graphite) to help with lubrication issues. Another sleeve material used for light to medium applications, called oil impregnated bronze sleeve bearings, contains pores that absorb oil, which is released under applied force and then reabsorbed back into the bearing once the force subsides.