Square Nuts ASNI/ASME B18.2.2 1986 Nominal Size Width Across Flats(F) Width Across Corners(G) Thickness(H) Basic Max Min Max Min Basic Max Min 1/4 7/16 .438 .425 .619 .554 7/32 .235 .203 5/16 9/16 .562 .547 .795 .721 17/64 .283 .249 3/8 5/8 .625 .606 .884 .802 21/64 .346 .310 7/16 3/4 .750 .728 1.061 .970 3/8 .394 .356 1/2 13/16 .812 .788 1.149 1.052 7/16 .458 .418 5/8 1 1.000 .969 1.414 1.300 35/64 .569 .525 3/4 1-1/8 1.125 1.088 1.591 1.464 21/32 .680 .632 7/8 1-5/16 1.312 1.269 1.856 1.712 49/64 .792 .740 1 1-1/2 1.500 1.450 2.121 1.961 7/8 .903 .847 1-1/8 1-11/16 1.688 1.631 2.386 2.209 1 1.030 .970 1-1/4 1-7/8 1.875 1.812 2.652 2.458 1-3/32 1.126 1.062