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 6220-00-358-9580
NSN 2925-01-545-2717
NSN 6105-00-717-8998
NSN 5835-01-013-9321
NSN 5996-00-405-9093
NSN 5835-01-132-5894
NSN 5998-01-422-8309
NSN 6135-01-490-7704
NSN 6620-01-301-3258
NSN 5950-01-386-0085
NSN 5996-01-104-4161
NSN 6320-00-343-1798