DIN 3182

DIN 3182 (originally Deutsche Industrienorm 'German industry standard', but now stands for Deutsches Institut für Normung 'German institute for standardization') was officially published in October 1932, but the 40mm thread type it standardized was in use by Central Powers since 1915, and throughout WWII mostly by the Axis. The thread pitch is 3,63 mm (1/7").