Thrust bearings are designed for side or axial loads, and cannot handle much radial load at all. The rolling element in a thrust bearing can be a ball, needle or roller. Thrust bearings come in both metric and inch sizes. Dimensions to consider when searching are the bore, the outside diameter and the overall width. Operating specifications to consider when searching for thrust bearings are rated speed, static axial load, and dynamic axial load. RPM for a bearing running in oil is going to be higher than one running in grease. The static axial load is the maximum axial load a bearing can withstand while stationary without suffering permanent damage. The dynamic axial load is the maximum axial load a bearing can withstand while revolving without suffering permanent damage. The Boca Bearing Company has a wide assortment of miniature, precision thrust bearings. 

The thrust ball bearings are classified into two kinds: unidirectional thrust bearing and bidirectional thrust bearing. The former can bear the axial force in one direction and the latter can bear he axial forces in two directions. Both unidirectional and bidirectional thrust ball bearings cannot bear any radial force.Ball bearings, or deep-groove bearings, extend the working life of equipment by enabling wheels, pulleys, and other rotating parts to reduce friction and move smoothly. Ball bearings have a series of round balls encased in a housing and support high axial or low-to-moderate radial loads.