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 6130-01-476-8472
NSN 6220-01-541-4064
NSN 6650-01-411-3904
NSN 5998-01-242-6782
NSN 6105-01-574-5670
NSN 5950-01-142-2634
NSN 5985-01-246-3725
NSN 6620-01-278-8028
NSN 5990-00-121-2134
NSN 6650-01-485-2351
NSN 5990-00-788-3829
NSN 5925-00-603-8077