7/8-9 ASTM A563 GRB HVY NUT HDG .022” ASTM A563 GRADE B HEAVY HEX NUT HDG ASME/ANSI B18.2.2 1987 IFI-7 AF 1.394-1.438” TH 0.833-0.855” Tapped Over Size per ASTM A 153 class C