8-3/30mm Vaccum Brazed Diamond engraving bits Specification: -Taper or Cone type with ball end(8-3mm) - workable length 30mm - Shank 8mm, - Total length 90mm Application: For granite & marble, masonry, ceramic tile, brick.... Feature: 1. 5-8times working life than electroplated diamond bits. High efficiency. 2. Used on CNC engraving machine, working at high rotating speed. 3. Different models for end milling, carving, line engraving, polishing, slotting, hollow-cutting, 3D embossment, cutting, flat processing ect.