SAE MA 1370A:2024-04-01

This standard specifies the characteristics of the MJ profile metric series of screw threads, altered from ISO 68 M Profile, to include a mandatory controlled radius of 0.18042P to 0.15011P at the root of the external thread and with the minor diameter of both external and internal threads increased to provide a basic thread height of 0.5625H in order to accommodate the external thread maximum root radius. The following detailed requirements are included: a MJ basic profile and design profiles b Standard series of diameter-pitch combinations for nominal thread diameters from 1.6 to 200 mm c Standard thread classes and form tolerances d Formulae for thread dimensions and tolerances e Method of designating MJ threads f Inspection requirement g Tables for selected diameter-pitch combinations for aerospace screws, bolts, nuts, shaft and bearing retaining screw threads, and fluid fittings thread sizes h Tables for MJ screw threads limiting dimensions and tolerances i Symbols for MJ thread dimensions and tolerances