This International Standard specifies the dimensions of machine chucking reamers with cylindrical shanks and Morse taper shanks. It deals with the following types of reamer: — machine chucking reamers with cylindrical shanks in the range from 1,32 mm to 20 mm diameter; — machine chucking reamers with Morse taper shanks in the range from 5,30 mm to 50 mm diameter. For each type of reamer, this International Standard gives two tables, one showing preferred sizes with corresponding dimensions, and the other being a general table set out as functions of diameter steps. Provision is also made for tolerances on lengths, cutting diameters and the diameters of cylindrical shanks.