This standard presents metric dimensions, tolerances, sizes and fits for straight bores, tapered bores, keys and keyways for un-mounted industrial flexible couplings. The keys and keyways followed the recommendations of ISO R773:1969 and shaft tolerances followed ISO R775:1969. Shaft keyway dimensions and tolerances were given in ISO R773:1969. This specification includes index tolerances for multiple keyways. Inspection methods for straight and tapered bores and keyways are included in the annexes. The annexes also include the recommended design practice for tapered shafts for use with flexible couplings.