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 6135-00-255-1340
NSN 5998-01-633-6845
NSN 5950-01-093-0348
NSN 5945-00-182-7384
NSN 5935-00-636-7393
NSN 5920-01-387-9972
NSN 6620-01-391-7331
NSN 5930-01-195-2332
NSN 4140-01-189-0217
NSN 5935-01-580-3501
NSN 5895-00-034-5679
NSN 5920-01-206-9947