Ball cage also called ball bearing bush, ball bearing bushing, ball bearing cage, ball Retainer.We produce three types ball cages. Resin base with ball, aluminium base with ball and copper base with cage. 1)Structure: standard ball cage, compact ball cage and Ultra compact ball cage.This design can decrease fatigue damage caused by rolling contact and side damage on machine parts and prolong service. Superior steel ball retainer with excellent performance of hardness, glossiness, buildiness, abrasion resistance, long service-life. 2)Specification: Max. loading capacity: 30N/mm2 Max. sliding speed: 6m/s Friction coefficient: 0.01-0.08 Fit tolerance: 0.01-0.02mm Hardness: HRC62-67 3)Applications: Transmissions, electric motors and generators pumps, compressors, gear boxes, drive elevator, textile machinery, printing machinery and other machinery industry like as cold punching die, precision machine tools and plastic mould. This produce is made of copper or aluminum or POM resin base material and well arranged steel ball. 4)When order tell us OD length and each quantity. For example: OD X Length - 100 PCS