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 5990-01-048-1056
NSN 5930-00-391-6323
NSN 5910-01-454-9833
NSN 5975-01-320-7363
NSN 5925-00-776-5062
NSN 6150-01-507-0092
NSN 6145-01-555-3465
NSN 6135-01-359-5798
NSN 5985-01-478-3433
NSN 5965-01-425-5857
NSN 6320-00-312-7348
NSN 5945-01-515-4334