HEAVY HEX NUT DIMENSIONS TABLE


Heavy hex nut dimensions sizes chart according to ASME B18.2.2. Width across flats (wrench size) and corners and hex and jam nut thickness are given for nut sizes between 1/4 to 4 inches. All dimensions are given in inches.

Hex Nut Dimensions
Nominal
 Size
Basic
Major
Diameter
of
Thread 
F G H H1
Width
Across
Flats
Width
Across
Corners
Thickness 
Heavy
Hex
Nut
Thickness
Heavy
Hex
Jam
Nuts
Basic min max. min. max. Basic min. max. Basic min. max.
1/4 0.2500 1/2 0.488 0.500 0.556 0.577 15/64 0.218 0.250 11/64 0.156 0.188
5/16 0.3125 9/16 0.546 0.562 0.622 0.650 19/64 0.280 0.314 13/64 0.186 0.220
3/8 0.3750 11/16 0.669 0.688 0.763 0.794 23/64 0.341 0.377 15/64 0.216 0.252
7/16 0.4375 3/4 0.728 0.750 0.830 0.866 27/64 0.403 0.441 17/64 0.247 0.285
1/2 0.5000 7/8 0.850 0.875 0.969 1.010 31/64 0.464 0.504 19/64 0.277 0.317
9/16 0.5625 15/16 0.909 0.938 1.037 1.083 35/64 0.526 0.568 21/64 0.307 0.349
5/8 0.6250 1 1/16 1.031 1.062 1.175 1.227 39/64 0.587 0.631 23/64 0.337 0.381
3/4 0.7500 1 1/4 1.212 1.250 1.382 1.443 47/64 0.710 0.758 27/64 0.398 0.446
7/8 0.8750 1 7/16 1.394 1.438 1.589 1.660 55/64 0.833 0.885 31/64 0.458 0.510
1 1.0000 1 5/18 1.575 1.625 1.796 1.876 63/64 0.956 1.012 35/64 0.519 0.575
Nominal
 Size
Major
Diameter
of
Thread  
F G H H1
Width
Across
Flats
Width
Across
Corners
Thickness 
Heavy
Hex
Nut
Thickness
Heavy
Hex
Jam
Nuts
Basic min max. min. max. Basic min. max. Basic min. max.
1 1/8 1.1250 1 13/16 1.756 1.812 2.002 2.093 1 7/64 1.079 1.139 39/64 0.579 0.639
1 1/4 1.2500 2 1.938 2.000 2.209 2.309 1 7/32 1.187 1.251 23/32 0.687 0.751
1 3/8 1.3750 2 3/16 2.119 2.188 2.416 2.526 1 11/32 1.310 1.378 25/32 0.747 0.815
1 1/2 1.5000 2 3/8 2.300 2.375 2.622 2.742 1 15/32 1.433 1.505 27/32 0.808 0.880
1 5/8 1.6250 2 9/16 2.481 2.562 2.828 2.959 1 19/32 1.556 1.632 29/32 0.868 0.944
1 3/4 1.7500 2 3/4 2.662 2.750 3.035 3.175 1 23/32 1.679 1.759 31/32 0.929 1.009
1 7/8 1.8750 2 15/16 2.844 2.938 3.242 3.392 1 27/32 1.802 1.886 1 1/32 0.989 1.073
Nominal
 Size
Major
Diameter
of
Thread  
F G H H1
Width
Across
Flats
Width
Across
Corners
Thickness 
Heavy
Hex
Nut
Thickness
Heavy
Hex
Jam
Nuts
Basic min max. min. max. Basic min. max. Basic min. max.
2 2.0000 3 1/8 3.025 3.125 3.449 3.608 1 31/32 1.925 2.013 1 3/32 1.050 1.138
2 1/4 2.2500 3 1/2 3.388 3.500 3.862 4.041 2 13/64 2.155 2.251 1 13/64 1.155 1.251
2 1/2 2.5000 3 7/8 3.750 3.875 4.275 4.474 2 29/64 2.401 2.505 1 29/64 1.401 1.505
2 3/4 2.7500 4 1/4 4.112 4.250 4.688 4.907 2 45/64 2.647 2.759 1 37/64 1.522 1.634
3 3.0000 4 5/8 4.475 4.625 5.102 5.340 2 61/64 2.893 3.013 1 45/64 1.643 1.763
3 1/4 3.2500 5 4.838 5.000 5.515 5.774 3 3/16 3.124 3.252 1 13/16 1.748 1.876
3 1/2 3.5000 5 3/8 5.200 5.375 5.928 6.207 3 7/16 3.370 3.506 1 15/16 1.870 2.006
3 3/4 3.7500 5 3/4 5.562 5.750 6.341 6.640 3 11/16 3.616 3.760 2 1/16 1.990 2.134
4 4.0000 6 1/8 5.925 6.125 6.755 7.073 3 15/16 3.862 4.014 2 3/16 2.112 2.264

Supplements:

Link Usage
Heavy hex nut dimensions calculator Calculator form of the heavy hex nut dimensions chart.


Reference:

  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2016) . Machinery's Handbook . 30th edition.  Industrial Press Inc. , pp 1595
  • ASME B18.2.2-2010, Square and Hex Nuts (Inch Series)