Alpha Countersink Single Flute 20mm CS1-20Countersink Single Flute 20mm Single flute construction is the most less aggressive and slower cutting than multi flutes, therefore reducing the risk of chattering permitting optimum performance for the handyman and portable power tools. Simple to sharpen by grinding the face of the flute Fully ground M42 HSS Co8 increases strength and countersink life 90 angle Suitable for countersinking non ferrous metals Angle (deg) 90 Diameter (mm) 20 Diameter