1136-CNC Small Bore Grooving Tool MGR Integral Tungsten Carbide Small Bore Hook Grooving Tool for Steel and Aluminum Internal Grooving ToolholderMGR Small Bore Bore Groove Cutter 1. Tungsten steel alloy to create shock resistant and practical Imported tungsten steel base material five axis linkage grinding from the whole tungsten carbide one piece molding 2. Mirror smooth and fine polishing inside the groove. Five axis CNC grinding sharp front angle, more smooth chip discharge. 3. Arc back corner, strong anti vibration Curved rear corner support, improve tool rigidity, meet the high speed