Nut is case hardened black oxide alloy steel
A nut, flat on top and bottom having 6 flat sides. For items which have internal tapered or straight (parallel) pipe threads, specific electrical conduit size designation, and which when installed, provide a method of tightening to lock the connection, see locknut, electrical conduit. See also locknut, tube fitting. For items having a thickness (or height) exceeding two times the width across the flats, use post, electrical-mechanical equipment. (when height or thickness and/or width across the flats is designated as a tolerance dimension, the maximum dimension will be used to determine compliance.)
Classification: Nuts of iron or steel
NSN 6685-00-147-8045
NSN 4140-01-243-5817
NSN 4140-00-832-9043
NSN 6620-01-337-8308
NSN 5965-01-161-3405
NSN 5975-01-377-2524
NSN 5925-01-469-8964
NSN 6240-01-332-5275
NSN 4140-01-598-4325
NSN 5999-00-450-1817
NSN 6110-01-249-6404
NSN 5945-01-604-8977