Some bearings operate in such hot environments that they fail due to extreme heat.
A new plane insert bearing housing from MRC Bearing Services, Kulpsville, Pa. (mrcbearingservices.com), lets bearings operate at temperatures to 500F. The steel inner and outer rings resist corrosion and wear, while a polymer sleeve insulates against heat and reduces friction to the point lubrication is unnecessary. The inserts fit bearings for shafts from 0.75 to 1.9375 in., and can mount vertically or horizontally. An antirotation slot in the outer ring mates with a setscrew in the housing, preventing the rings and inserts from rotating. The inserts have USDA approval for use with direct or incidental food contact.