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 5999-00-932-3690
NSN 5855-00-560-0110
NSN 6610-01-027-8736
NSN 6320-00-164-4087
NSN 5999-00-984-2640
NSN 5945-01-077-7943
NSN 6645-00-960-6594
NSN 6685-01-014-3150
NSN 4140-01-123-8801
NSN 7035-01-145-5059
NSN 5920-00-536-1842
NSN 5935-01-237-8826