Rod ends consist of an eye-shaped head with integral shank which forms a housing for a standard spherical plain bearing. As a rule, rod ends are available with left or right-hand female (internal) or male (external) threads to ISO 965/1:1980. Where rod ends are needed for specific applications - primarily those where a rod end is attached to the end of a piston rod or at the base of a hydraulic cylinder - rod ends are available with slotted shank and compressible threaded section or with a "welding shank" i.e. a shank suitable for welding to another component. SKF rod ends which require maintenance are available as standard with the sliding contact surface combinations steel-on-steel and steel-on-bronze. Both types of rod end require regular relubrication. Steel-on-steel rod ends have sliding contact surfaces which are hardened, phosphated and treated with a running-in lubricant. They are very resistant to wear and therefore particularly suitable for applications where heavy loads of alternating direction have to be accommodated. Steel-on-bronze rod ends have a hardened and chromium plated inner ring and a bronze outer ring. Their performance under conditions of lubricant starvation is therefore very good.