5306-00-421-6653 (AN3-18A)
NSN 5306-00-421-6653 (NIIN 00-421-6653) is a machine bolt in Federal Supply Class 5306, Bolts — an externally threaded fastener designed for insertion through holes in assembled parts and normally intended to be tightened or released by torquing a nut. Manufacturer part number AN3-18A (Aeronautical Standards Group Dept Of, CAGE 88044).
Key specs: finished head; 26 rockwell c minimum and 32 rockwell c maximum overall hardness; full characteristics table below. NIIN assigned December 1970; DEMIL A (none required).