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 6240-00-269-3346
NSN 7035-01-529-4603
NSN 7035-01-502-6764
NSN 6320-01-185-3857
NSN 6650-01-220-3842
NSN 6650-01-659-1950
NSN 6110-01-399-8587
NSN 5915-00-040-9073
NSN 5985-00-832-9988
NSN 5930-00-792-0798
NSN 6145-01-202-2054
NSN 6685-01-297-1628