Thread series is hf
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 6145-00-683-5353
NSN 5975-01-141-4948
NSN 5910-01-094-5891
NSN 6110-01-448-1554
NSN 5910-00-263-0462
NSN 5999-01-331-4718
NSN 6650-01-201-2956
NSN 6220-01-411-3993
NSN 6650-01-515-0391
NSN 5996-01-460-4396
NSN 5920-00-504-8634
NSN 5998-01-429-8970