They are made of hardened M2 high speed steel and are precision ground for excellent performance throughout the cut and long tool life. They require less horsepower and thrust to cut, and last much longer than traditional holemaking methods. Rotabroach® cutters have a 3/4" diameter double-flatted shank. Modified end tooth geometry is also available for drilling into stacked plate applications. For extended tool life and lower cost per hold Rotabroach® Cutters are resharpenable.