A study was conducted to compare the friction characteristics of ball bushings and plastic plain bearings for a low-speed mechanical drive. The goal was freedom from stick-slip behavior.

Laboratory tests were conducted to measure the static and kinetic coefficient of friction of 12 bushing/shaft couples. The test results indicated that the most consistent friction characteristics were obtained with bushings made from oil-impregnated ultrahigh molecular weight polyethylene sliding on a hardened steel shaft with a surface roughness of 0.2μm Ra. The variability of the friction force is proposed as the parameter to be measured when freedom from stick-slip behavior is the system goal.