It is valid when the following conditions occur: the screwing length is between 1 and 2.5 times the nominal thread diameter; the limit dimensions of the average diameters indicated in tables III and IV are satisfied by verifying them both with the three roller method or with adjustable gauges and with profiled gauges, which involve a thread length equal to 8 times the pitch. The limit dimensions prescribed for screws apply to finished threads with or without coating, coarse pitch with a nominal diameter of 5 to 24 mm and fine pitch with a nominal diameter of 8 to 24 mm as per UNI 4536-64. Tolerance system; fundamental tolerances and deviations (see UNI 5541-65); limit dimensions of threads for screws and nuts.
UNI 7324-1974 history
1974UNI 7324-1974 ISO metric threads with triangular profile. Tolerance system for interference fits.