This International Standard deals with — shell reamers with taper bore, taper 1 : 30 (included) with slot drive (Tables 1 and 2); — the corresponding arbors for shell reamers (Tables 3 and 4). It gives dimensions — for shell reamers with outside diameters above 19,9 mm (0.783 5 in) up to and including 101,6 mm (4 in) having taper bores with large end diameters d1 from 10 mm (0.393 7 in) to 50 mm (1.968 5 in) and for the corresponding arbors; — for shell reamer slots and arbor tenons (Tables 5 and 6), in order to ensure interchangeability of shell reamers and corresponding arbors, and details of a method of checking the taper elements. It supplements ISO/R 236 and ISO/R 521.