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.)
Maritime Administration 
Dept. of the Army 
Dept. of the Air Force 
U.s. Marine Corps 
Dept. of the Navy 
Defense Logistics Agency 
U.s. Coast Guard 
Bureau of Mines 
Bureau of Reclamation 
Government Printing Office 
National Aeronautics and Space Administration
National Aeronautics and Space Administration
National Aeronautics and Space Administration
National Aeronautics and Space Administration 
General Services Administration 
Austria 
Lithuania 
Poland 
U.s. Postal Service - Procurement and Supplies Dept. 
Brazil 
Spain 
Singapore 
Kuwait 
Morocco 
Malaysia 
Thailand 
Australia 
Canada 
New Zealand 
France 
Germany 
Republic of Korea 
United Kingdom 
Philippines 
Netherlands 
Portugal 
Italy 
Norway 
Greece 
Turkey Classification: Nuts of iron or steel
NSN 6610-01-563-4312
NSN 6610-00-273-9019
NSN 6240-00-933-4188
NSN 6610-00-456-0485
NSN 4140-01-431-9821
NSN 5910-00-165-0629
NSN 6320-01-359-3921
NSN 5999-01-500-5888
NSN 5998-01-528-9403
NSN 5835-01-241-1090
NSN 5945-00-912-1809
NSN 6650-01-447-2858