Nut, hex, heavy duty (requested name)
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.)
NSN 6610-01-227-1692
NSN 4140-00-287-9199
NSN 5985-01-444-4517
NSN 5945-01-649-5569
NSN 6110-00-488-9364
NSN 6650-01-543-7045
NSN 6240-01-249-5182
NSN 6105-01-184-9504
NSN 5960-01-553-4557
NSN 5990-01-037-1704
NSN 6130-01-237-5992
NSN 5920-01-114-5439