... working time3. Highest engraving effiency4. Lowest unit costIntrustion for use of diamond burin:* For drilling, reaming, polishing, lettering, etc on ... Non-collision in the process of working with these diamond tools which are hard and brittle.* Best REV of 3000 ... 3mm in case the workpiece is curshed. brazed diamond engraving tools | sintered diamond burin for engraving jade, stone, granite,etc.