... fastener Name: hex nut with internal thread and castle screw Ability for the material of this kind of nut: Grade3. ... .9,etcCarbon steelGr.B,Gr.C,Gr.D,Gr.36,Gr.58,1010,1015,1016,1020,1045,etcAlloy steel4130, ... spray coating,electrophoretic coating,etc Polishing Grinding and polishing,etc,except mirror finishAbility for the tolerance: Roundess0.002mmCylindricity0.003mmRoughnessRa0.32Straightness0.01 ...