... nonferrous metals( such as marble, gemstone, bone, etc), the machining workpiece’s hardness can be upto HRC70.2. may replace ... instances, and no dust pollution.3. good machining quality, high fine finish, suitable for machining various mold cavity with high precision.4. ... .6. more economic, may reduce about 10 times for comprehesive machining cost.Carbide rotary burrs is generally drived by handled ...