drive shaft 1.Material:S45C 2.Size tolerance:+/-0.002 3.Technology: Head rolled thread edge milling 4 Hardness:HRC22-25 drive shaft1.Material:S45C2.Hardness:HRC22°-25°3.Surface roughness:0.02μm4.Size tolerance:+-0.002mm5.Diameter:13.5mm6.length:135mm7.Technology:Head rolled thread .edge milling starter drive shaft