Bearings are mechanical assemblies that consist of rolling elements and usually inner and outer races which are used for rotating or linear shaft applications, and there are several different types of bearings, including ball and roller bearings, linear bearings, as well as mounted versions that may use either rolling element bearings or plain bearings. Ball bearings have spherical rolling elements and are used for lower load applications, while roller bearings use cylindrical rolling elements for heavier load carrying requirements. Linear bearings are used for linear movements along shafts and may also have rotational capabilities. Mounted bearings are assemblies in which the bearings are pre-assembled in mountings that, in turn, are bolted to frames, stanchions, etc., and are used for supporting the ends of shafts, conveyor rollers, etc. In addition to ball and roller bearings in their radial, linear, and mounted forms, bearings include those for civil engineering applications, which are called slide bearings; those used in small instruments and the like, known as jewel bearings; and very specialized bearings known collectively as frictionless bearings which includes air and m...