1/2 -13 ASTM A563 DH HVY NUT HDG .018” ASTM A563 DH HEAVY HEX NUT HDG ASME/ANSI B18.2.2 1987 IFI-7 AF 0.850 – 0.875” THK 0.464 – 0.504” TAPPED OVER SIZE PER ASTM A 153 CLASS C, WAXED & LUBRICATED