Limit number is h3; in accordance with us army drawing 11b5090651
An internal threading tool with longitudinally separated cutting edges designed to form specific threads.
Classification: Tools for tapping or threading, parts thereof, of base metal
NSN 5965-01-432-1943
NSN 5990-01-609-4793
NSN 5895-01-250-2813
NSN 5985-00-366-5192
NSN 5975-00-523-7950
NSN 5930-01-271-3344
NSN 6610-01-445-1036
NSN 5935-01-129-3239
NSN 5960-00-116-1965
NSN 5935-01-660-1277
NSN 7035-01-088-6415
NSN 6685-01-166-8886