... in special fastener 1,Name:Steel pipe joint;Pipe joint;Steel joint2,For the similar joint,what can we do ?(1), Ability for ... the material of this kind of joint: Grade3.6,4.6,4.8,5.6,6.8 ... ,electrophoretic coating,etc Polishing Grinding and polishing,etc,except mirror finish (3),Ability for the tolerance Roundess0.002mmCylindricity0.003mmRoughnessRa0.32Straightness0.01 ...