... fastner field 1,Name: Black steel hinge pin;Steel hinge pin;Black hinge pin 2,For the similar hinge pin,what can we do ... copper plated,gold plated,chrome(3+Rohs &6+ ) plated,anodic oxidation,etc Dip plating black oxide coating,hot dip ... etc Polishing Grinding and polishing,etc,except mirror finish (3),Ability for the tolerance Roundess0.002mmCylindricity0.003mmRoughnessRa0.32Straightness0.01 ...