HSB may provide IR and the LR male British system and the special size inner loop, Has the oil hole inner loop.
The IR inner loop size common difference and the geometry precision conform to the present standard, The LR inner loop end surface after has not rubbed truncates, The size common difference and the geometry precision are bigger than IR, But two kind of inner loops both pass through the heat treatment.
Belt lubricating hole ■ belt lubricating hole, Has not guided the bevel edge.