Features The single-acting thrust ball bearing consisting of two groove washers and a set of balls within a cage. Under axial load and favourable rolling conditions, the balls are guided in the apex of the groove. The conditions become less favourable when centrifugal forces push the balls outward at high rotary speeds and very low loads. Small and medium-sized thrust ball bearings are, for normal operation, equipped with pressed steel cages; large bearings are provided with machined steel or brass cages. Thrust ball bearings are designed for supporting axial forces; they are employed where the axial forces are too high to be transmitted by radial bearings or where a rigid guidance is required.