1/2-13 GR2 HEX NUT MECH GALV .018” SAE J995 GRADE 2 HEX NUT MECHANICAL GALVANIZED ASME/ANSI B18.2.2 1987 IFI-7 AF 0.736-0.750” TH 0.427-0.488” Tapped Over Size per ASTM A 153 class C