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ASME B18.2.1 Heavy Hex bolts, Inch Series

ASME B18.2.1 Heavy Hex Bolts

Dimensions of ASME B18.2.1 Heavy Hex Bolts

Nominal Size or
Basic product Diameter
Full Size Body Diameter, E Width Across Flats, F Width Across Corners, G Head Height, H Radius of Fillet, R Thread Length for
Bolt Lengths, LT
6 in. and Shorter Over 6 in.
Max Min Basic Max Min Max Min Basic Max Min Max Min Nom Nom
3/8 0.3750 0.388 0.360 11/6 0.688 0.669 0.794 0.763 1/4 0.268 0.226 0.03 0.01 1.000 1.250
1/2 0.5000 0.515 0.482 7/8 0.875 0.850 1.010 0.969 11/32 0.364 0.302 0.03 0.01 1.250 1.500
5/8 0.6250 0.642 0.605 11/16 1.062 1.031 1.227 1.175 27/64 0.444 0.378 0.06 0.02 1.500 1.750
3/4 0.7500 0.768 0.729 1 1/4 1.250 1.212 1.443 1.383 1/2 0.524 0.455 0.06 0.02 1.750 2.000
7/8 0.8750 0.895 0.852 1 7/16 1.438 1.394 1.660 1.589 37/64 0.604 0.531 0.06 0.02 2.000 2.250
1 1.000 1.022 0.976 1 5/8 1.625 1.575 1.876 1.796 43/64 0.700 0.591 0.09 0.03 2.250 2.500
1 1/8 1.1250 1.149 1.098 1 13/16 1.812 1.756 2.093 2.002 3/4 0.780 0.658 0.09 0.03 2.500 2.750
1 1/4 1.2500 1.277 1.223 2 2.000 1.938 2.309 2.209 27/32 0.876 0.749 0.09 0.03 2.750 3.000
1 3/8 1.3750 1.404 1.345 2 3/16 2.188 2.119 2.526 2.416 29/32 0.940 0.810 0.09 0.03 3.000 3.250
1 1/2 1.5000 1.531 1.470 2 3/8 2.375 2.300 2.742 2.622 1 1.036 0.902 0.09 0.03 3.250 3.500
1 5/8 1.6250 1.658 1.591 2 9/16 2.562 2.481 2.959 2.829 1 3/32 1.116 0.978 0.09 0.03 3.500 3.750
1 3/4 1.7500 1.785 1.716 2 3/4 2.750 2.662 3.175 3.035 1 5/32 1.196 1.054 0.12 0.04 3.750 4.000
1 7/8 1.8750 1.912 1.839 2 15/16 2.938 2.844 3.392 3.242 1 1/4 1.276 1.130 0.12 0.04 4.000 4.250
2 2.000 2.039 1.964 3 1/8 3.125 3.025 3.608 3.449 1 11/32 1.388 1.175 0.12 0.04 4.250 4.500
2 1/4 2.2500 2.305 2.214 3 1/2 3.500 3.388 4.041 3.862 1 1/2 1.548 1.327 0.19 0.06 4.750 5.000
2 1/2 2.5000 2.559 2.461 3 7/8 3.875 3.750 4.474 4.275 1 21/32 1.708 1.479 0.19 0.06 5.250 5.500
2 3/4 2.7500 2.827 2.711 4 1/4 4.250 4.112 4.907 4.688 1 13/16 1.869 1.632 0.19 0.06 5.750 6.000
3 3.000 3.081 2.961 4 5/8 4.625 4.475 5.340 5.102 2 2.060 1.815 0.19 0.06 6.250 6.500

Dimensions of Screw Threads

Nomianal Size or Basic product Diameter Threads per inch. Major Diameter Root Diameter Length Tolerance
Max. Min. Max. Min. ≥ 6 in. > 6 in.
No. 10 0.190 11 0.199 0.178 0.122 0.107 ±0.12 ±0.25
1/4 0.250 10 0.260 0.237 0.177 0.160 ±0.12 ±0.25
5/16 0.312 9 0.324 0.298 0.228 0.210 ±0.12 ±0.25
3/8 0.375 7 0.388 0.360 0.268 0.250 ±0.12 ±0.25
1/2 0.500 6 0.515 0.482 0.374 0.354 ±0.12 ±0.25
5/8 0.625 5 0.642 0.605 0.473 0.453 ±0.25 ±0.25
3/4 0.750 4 1/2 0.768 0.729 0.582 0.562 ±0.25 ±0.25
7/8 0.875 4 0.895 0.852 0.686 0.665 ±0.25 ±0.25
1 1.000 3 1/2 1.022 0.976 0.784 0.760 ±0.25 ±0.25
1 1/8 1.125 3 1/4 1.149 1.100 0.892 0.867 ±0.25 ±0.25
1 1/4 1.250 3 1/4 1.277 1.223 1.017 0.987 ±0.25 ±0.25