MS51966 Flat Point Hex Socket Set Screw, Plain and Self Locking, Alloy Steel, Cad Plated. UNF-3A (S/S by NASM51955, 27 OCT 1999). Socket Set Screws come in different types and sizes including: AN565, MS18063, MS18064, MS51021, MS51023, MS51029, MS51031, MS51038, MS51045, MS51963, MS51964, MS51965, MS51966, NAS1081. MS51966A, MILITARY STANDARD: SETSCREW – HEXAGON SOCKET, FLAT POINT, ALLOY STEEL, CADMIUM PLATED, UNF-3A, PLAIN AND SELF-LOCKING (27 OCT 1999) [SUPERSEDED BY NASM51955].