Square and Hex Machine Screw Nuts ANSI/ASME B18.6.3 1972 Width Across Flats(F) Width Across Corners(G) #0 5/32 .156 .150 .221 .206 .180 .171 .050 .043 #1 5/32 .156 .150 .221 .206 .180 .171 .050 .043 #2 3/16 .188 .180 .265 .247 .217 .205 .066 .057 #3 3/16 .188 .180 .265 .247 .217 .205 .066 .057 #4 1/4 .250 .241 .354 .331 .289 .275 .098 .087 #5 5/16 .312 .302 .442 .415 .361 .344 .114 .102 #6 5/16 .312 .302 .442 .415 .361 .344 .114 .102 #8 11/32 .344 .332 .486 .456 .397 .378 .130 .117 #10 3/8 .375 .362 .530 .497 .433 .413 .130 .117 #12 7/16 .438 .423 .619 .581 .505 .482 .161 .148 1/4 7/16 .438 .423 .619 .581 .505 .482 .193 .178 5/16 9/16 .562 .545 .795 .748 .650 .621 .225 .208 3/8 5/8 .625 .607 .884 .833 .722 .692 .257 .239
Nominal Size
Thickness(H)
Square
Hex
Basic
Max
Min
Max
Min
Max
Min
Max
Min