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 5999-01-343-3648
NSN 6135-01-238-2878
NSN 6320-01-544-6447
NSN 6240-00-483-7038
NSN 5998-01-474-1077
NSN 6105-01-029-3764
NSN 6145-00-340-6698
NSN 6145-00-388-9084
NSN 6620-00-975-5159
NSN 5895-00-354-1614
NSN 6105-01-525-2052
NSN 5915-00-432-9284