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 5998-01-540-4278
NSN 6685-01-437-8880
NSN 5960-01-614-8005
NSN 5915-01-278-7065
NSN 5930-00-706-7865
NSN 5999-01-383-5576
NSN 5905-00-892-7289
NSN 5998-01-410-7788
NSN 6240-00-686-5345
NSN 5985-00-863-7908
NSN 6135-01-487-0773
NSN 6105-01-363-0487