This International Standard specifies the dimensions of Morse taper shank countersinks for angles 60°, 90° and 120° inclusive.It specifies dimensions in metric units only, these being regarded as the only recommended dimensions in the future, for countersinks with cutting diameters in the range 16 mm to 80 mm.The dimensions given apply only to tools made from high speed steel. However, if the method of production allows, the shanks may be manufactured from a suitable alternative material, such as a carbon steel.The Morse taper shanks are in accordance with ISO 296.Unless otherwise indicated, the countersinks will be right-hand cutting.Parallel shank countersinks are the subject of ISO 3294.