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 6105-01-586-6244
NSN 5945-01-088-8071
NSN 6105-00-886-0529
NSN 5999-01-186-9631
NSN 5835-01-099-8702
NSN 6240-01-348-8975
NSN 6110-01-494-4717
NSN 7035-01-533-5770
NSN 6130-01-288-9990
NSN 5950-01-194-1572
NSN 5999-01-490-5835
NSN 6130-00-141-8317