UN100-108 | Holemaker Bi-Metal Holesaw 108mm Dia. PREMIUM QUALITY BI-METAL M42 COBALT HIGH SPEED STEEL. Suitable for drilling a wide range of materials including steel aluminium brass cast iron plastics & wood. The M42 (8% Cobalt) high speed steel teeth offer optimal cutting life & performance. VARIABLE PITCH 4 / 6 TEETH PER INCH. For reduced vibration delivering increased life performance & accuracy. • Diameter: 108mm (4-1/4 ) • Thread: 5/8