... special fastener field Name: steps nut;Machined screw cap;Steel screw capAbility for the material of this kind ... etcBronzeC51900,C60600,C17200,etcAlumimum100,5052,6061,6063,etcAbility for the surface finish: ElectroplateZinc plated(while,colour, ... Polishing Grinding and polishing,etc,except mirror finishAbility for the tolerance: Roundess0.002mmCylindricity0.003mmRoughnessRa0.32Straightness0.01/200mm ...