• Bearing roller  size range: Dw:3~100, Lw:5~100; The material (bearing steel) makes by the GCr15 steel, its degree of hardness is HRC58~64; Surface roughness Ra is not bigger than 0.2 mm also mass production piston pin, the crank pin and other pins, generally (bearing steel) makes with the Gcr15 steel, its precision, the skin hardness and roughness and so on conform to the related profession standard, or satisfies the user request. 　　
• diameter tolerance over all batches +/-0.01mm

            diameter tolerance within a batch +/-0.003

            all rollers crowned or not

            length tolerance +/-0.1mm

            recess on the ends or not

            hardness rockwell c 58 to 62

            chrome material GN grade