ASME B18.2.1 Heavy Hex Screws

ASME B18.2.1 Heavy Hex Screws

ASME B18.2.1 Heavy Hex Screws

Dimensions of ASME B18.2.1 Heavy Hex Screws

Nominal Size or Basic product Diameter Body Diameter, E Width Across Flats, F Width Across Corners, G Head Height, H Minimum Wrenching Height, J Thread Length for Screws Lengths, LT Transition Thread Length, Y Maximum Total Runout of Bearing Surface FIM
6 in. & Shorter Over 6 in.
Max. Min. Max. Min. Max. Min. Max. Min. Nom. Nom.
3/8 0.3750 0.3750 0.360 0.688 0.669 0.794 0.763 0.243 0.226 0.160 1.000 1.250 0.312 0.014
1/2 0.5000 0.5000 0.482 0.875 0.850 1.010 0.969 0.323 0.302 0.215 1.250 1.500 0.385 0.016
5/8 0.6250 0.6250 0.605 1.062 1.031 1.227 1.175 0.403 0.378 0.269 1.500 1.750 0.455 0.019
3/4 0.7500 0.7500 0.729 1.250 1.212 1.443 1.383 0.483 0.455 0.324 1.750 2.000 0.500 0.022
7/8 0.8750 0.8750 0.852 1.438 1.394 1.660 1.589 0.563 0.531 0.378 2.000 2.250 0.556 0.025
1 1.0000 1.000 0.976 1.625 1.575 1.876 1.796 0.627 0.591 0.416 2.250 2.500 0.625 0.028
1 1/8 1.1250 1.1250 1.098 1.812 1.756 2.093 2.002 0.718 0.658 0.461 2.500 2.750 0.714 0.032
1 1/4 1.2500 1.2500 1.223 2.000 1.938 2.309 2.209 0.813 0.749 0.530 2.750 3.000 0.714 0.035
1 3/8 1.3750 1.3750 1.345 2.188 2.119 2.526 2.416 0.878 0.810 0.569 3.000 3.250 0.833 0.038
1 1/2 1.5000 1.5000 1.470 2.375 2.300 2.742 2.622 0.974 0.902 0.640 3.250 3.500 0.833 0.041
1 5/8 1.6250 1.6250 1.591 2.562 2.481 2.959 2.829 1.038 0.962 0.694 3.500 3.750 0.909 0.044
1 3/4 1.7500 1.7500 1.716 2.750 2.662 3.175 3.035 1.134 1.054 0.748 3.750 4.000 1.000 0.048
1 7/8 1.8750 1.8750 1.839 2.938 2.844 3.392 3.242 1.198 1.114 0.802 4.000 4.250 1.000 0.052
2 2.000 2.000 1.964 3.125 3.025 3.608 3.449 1.263 1.175 0.825 4.250 4.500 1.111 0.055
2 1/4 2.2500 2.2500 2.214 3.500 3.388 4.041 3.862 1.423 1.327 0.933 -- 5.000 1.111 0.061
2 1/2 2.5000 2.5000 2.4610 3.8750 3.750 4.474 4.275 1.583 1.479 1.042 -- 5.500 1.250 0.068
2 3/4 2.7500 2.7500 2.7110 4.2500 4.112 4.907 4.688 1.744 1.632 1.151 -- 6.000 1.250 0.074
3 3.000 3.000 2.9610 4.6250 4.475 5.340 5.102 1.935 1.815 1.290 -- 6.500 1.250 0.081
3 1/4 3.2500 3.2500 3.2100 5.0000 4.838 5.774 5.515 2.126 1.998 1.399 -- 7.000 1.250 0.081
3 1/2 3.5000 3.5000 3.4610 5.3750 5.200 6.207 5.928 2.256 2.120 1.484 -- 7.500 1.250 0.098
3 3/4 3.7500 3.7500 3.7109 5.7500 5.562 6.640 6.341 2.447 2.303 1.612 -- 8.000 1.250 0.105
4 4.0000 4.0000 3.9609 6.1250 5.925 7.073 6.755 2.576 2.424 1.697 -- 8.500 1.250 0.112
4 1/4 4.2500 4.2500 4.2228 6.5000 6.288 7.506 7.168 2.768 2.608 1.826 -- 9.000 1.250 0.119
4 1/2 4.5000 4.5000 4.4727 6.8750 6.650 7.939 7.581 2.896 2.728 1.910 -- 9.500 1.250 0.126
4 3/4 4.7500 4.7500 4.7227 7.2500 7.012 8.372 7.994 3.088 2.912 2.038 -- 10.000 1.250 0.133
5 5.0000 5.000 4.9726 7.6250 7.375 8.805 8.408 3.217 3.033 2.123 -- 10.500 1.250 0.14
5 1/4 5.2500 5.2500 5.2226 8.0000 7.738 9.238 8.821 3.408 3.216 2.251 -- 11.000 1.250 0.147
5 1/2 5.5000 5.5000 5.4726 8.3750 8.100 9.671 9.234 3.538 3.338 2.337 -- 11.500 1.250 0.154
5 3/4 5.7500 5.7500 5.7225 8.7500 8.462 10.104 9.647 3.729 3.521 2.465 -- 12.000 1.250 0.161
6 6.0000 6.000 5.9725 9.1250 8.825 10.537 10.060 3.858 3.642 2.549 -- 12.500 1.250 0.168

Note:
Wrenching Height J, is a distance measured from the bearing surface up the side of the head at the corners. The width across corner shall be within specified limits for the full wrenching height.

ASTM A193 Grade B8C Fastener Coatings