This International Standard lays down the dimensions of machine taper pin reamers with Morse taper shanks. It covers only metric dimensions, which are the only recommended dimensions in the future for these types of reamers. The reamers have been designed to produce holes for taper pins manufactured to ISO 2339, in the range 5 to 50 mm nominal diameter. Unless otherwise stated these reamers will be right-hand cutting. The flutes may be straight or left-hand spiral at the option of the manufacturer. Hand taper pin reamers are dealt with in ISO 3465, and machine taper pin reamers with parallel shanks in ISO 3466.