This standard establishes the general dimensions of short machine and hand taps and essentially applies to taps with a relieved shank. These taps are used to produce ISO metric triangular profile threads with coarse pitch and fine pitch with a diameter from 3 to 10 mm.
UNI 7458-1975 history
1975UNI 7458-1975 Short machine taps and hand taps with cast-in handle for ISO metric threads of triangular cross-section