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 5930-01-340-9146
NSN 6650-01-590-7622
NSN 5999-00-288-5954
NSN 6650-00-854-0265
NSN 5975-00-004-9431
NSN 2925-00-684-7708
NSN 5905-00-251-5144
NSN 5998-00-317-5623
NSN 5910-01-508-4674
NSN 6645-00-220-2458
NSN 6110-00-999-8909
NSN 5915-01-030-6112