Care should be taken when machining to prevent the oil pores from being closed due to mearing and preventing
the oil from weeping out. Grinding or metal working operations should not be employed. When machining, only sharp
diamond or carbide cutting tools should be used, with a maximum of 0.2 mm radius.
Cut conditions Roughing Dressing
Cut speed (m/min.) 160-210 150-200
Forward feed (mm/rotation) up to 0,4 up to 0,2
Rate of cut (mm) up to 2,0 0,2-0,4
Intersection angle at the turning chisel:
Relief angleA = 6° - 8°
Wedge angleB = 70° - 75°
Effective cutting angleC = 9° - 12°
Do not use liquid coolants when machining porous, powdered metal bearings, at jet of air for cooling purposes is recommended. It is essential to clean bearings carefully after machining. It may be necessary to replenish lost oil after machining. This can be accomplished by putting the bearings into a container filled with heated oil, and, subsequently is allowed to cool. Generally, SAE 20 W oil is utilized, with a viscosity of 3.5 L or similar oil, heated to 80 degrees C. The parts are kept in the oil bath until oil has cooled down.