... ) and nonferrous metals( such as marble, gemstone, bone, etc), the machining workpiece’s hardness can be upto HRC70.2. may replace ... .6. more economic, may reduce about 10 times for comprehesive machining cost.Carbide rotary burrs is generally drived by handled electric ... , circular bead or groove on the machinery parts.5. Finish machining of wide variety of machinery parts of die cavities.6 ...