Guide pin SUJ2 Material ， Hardness HRC58 and above，Subject to heat treatment and abrasive machining; Contribute to extremely excellent toughness, finish and positioning properties; Of high work precision and grinding resistance. SUJ2 Material ， Hardness HRC5 and above，Guide bushing：SUJ2 Material ， Hardness HRC58 and above，After abrasive machining, it can amount to a dimensional precision of 0.005mm and a coaxiality of ф0.005mm. A kind of oil-free guide bushing with mosaic structure of MoS2 and copper alloy is available to improve the grinding resistance.