Trend 50/51 x 8mm HSSE Helical Plunge Bit 8mmTooling for use on webbed aluminium and UPVC extrusions by window and door fabricators. Cutters are produced in special high speed steel (HSSE) to ensure a clean cut and resist the abrasive nature of anodised aluminium extrusions. Cutters are designed to plunge and machine or mill lateral slots All tooling for aluminium should be used with a coolant, wax stick, or lubricant. The material being worked on should always be securely clamped in a machine