... for the material of this kind of finger: Grade3.6,4.6,4.8,5.6,6.8,8.8,9.8 ... ,etcAlumimum100,5052,6061,6063,etc(2),Ability for the surface finish: ElectroplateZinc plated(while,colour ... polishing,etc,except mirror finish (3),Ability for the tolerance Roundess0.002mmCylindricity0.003mmRoughnessRa0.32Straightness0.01/ ... that you could avoid lots of risks.P.S:For us,the most competitive industry is machined ...