Hexagonal Heavy-series nuts used with stud bolt. Heavy hex nut dimensions in inches are covered in ASME B18.2.2 Square and Hex Nuts, however, the dimensions in matrix unit are covered in ASME B18.2.4.6M Heavy Hex Nuts. Here, I have listed the Heavy hex nut dimensions as per ISO and UNC.
ISO Heavy hex nut dimensions
ISO Nut NB | Across Corners | MAX Thickness | MIN Thickness | MAX Across Flats | MIN Across Flats |
M 8 | 14.38 | 6.8 | 6.44 | 13 | 12.73 |
M 10 | 17.77 | 8.4 | 8.04 | 16 | 15.73 |
M 12 | 20.03 | 10.8 | 10.37 | 18 | 17.73 |
M 14 | 23.35 | 12.8 | 12.1 | 21 | 20.67 |
M 16 | 26.75 | 14.8 | 14.1 | 24 | 23.67 |
M 18 | 29.56 | 15.8 | 15.1 | 27 | 26.16 |
M 20 | 32.95 | 18 | 16.9 | 30 | 29.16 |
M 22 | 37.29 | 19.4 | 18.1 | 34 | 33 |
M 24 | 39.55 | 21.5 | 20.2 | 36 | 35 |
M 27 | 45.2 | 23.8 | 22.5 | 41 | 40 |
M 30 | 50.85 | 26.6 | 24.3 | 46 | 45 |
M 33 | 55.37 | 28.7 | 27.4 | 50 | 49 |
M 36 | 60.79 | 31 | 29.4 | 55 | 53.8 |
M 39 | 66.44 | 33.4 | 31.8 | 60 | 58.8 |
M 42 | 71.3 | 34 | 32.4 | 65 | 63.1 |
M 45 | 76.95 | 36 | 34.4 | 70 | 68.1 |
M 48 | 82.6 | 38 | 39.4 | 75 | 73.1 |
M 52 | 88.25 | 42 | 40.4 | 80 | 78.1 |
M 56 | 93.56 | 45 | 43.4 | 85 | 82.8 |
M 60 | 99.21 | 48 | 46.4 | 90 | 87.8 |
M 64 | 104.86 | 51 | 49.1 | 95 | 92.8 |
M 68 | 110.51 | 54 | 52.1 | 100 | 97.8 |
M 72 x 6 | 116.16 | 58 | 56.1 | 105 | 102.8 |
M 76 x 6 | 121.81 | 61 | 59.1 | 110 | 107.8 |
M 80 x 6 | 127.46 | 64 | 62.1 | 115 | 112.8 |
UNC Heavy hex nut dimensions
UNC Nut N/B | Max Across Corners | Min Across Corners | Max Thickness | Min Thickness | Max Across Flats | Max Across Flats |
3/8 | 20.2 | 19.4 | 9.6 | 8.7 | 17.5 | 17 |
7/16 | 22 | 21.1 | 11.2 | 10.2 | 19 | 18.5 |
1/2 | 25.6 | 24.6 | 12.8 | 11.8 | 22.2 | 21.6 |
9/16 | 27.5 | 26.3 | 14.4 | 13.4 | 23.8 | 23.1 |
5/8 | 31.2 | 29.8 | 16 | 14.9 | 27 | 26.2 |
3/4 | 36.7 | 35.1 | 19.3 | 18 | 31.8 | 30.8 |
7/8 | 42.2 | 40.4 | 22.5 | 21.2 | 36.5 | 35.4 |
1 | 47.7 | 45.6 | 25.7 | 24.3 | 41.3 | 40 |
1 1/8 | 53.2 | 50.8 | 28.9 | 27.4 | 46 | 44.6 |
1 1/4 | 58.6 | 56.1 | 31.8 | 30.1 | 50.8 | 49.2 |
1 3/8 | 64.2 | 61.4 | 35 | 33.3 | 55.6 | 53.8 |
1 1/2 | 69.6 | 66.6 | 38.2 | 36.4 | 60.3 | 58.4 |
1 5/8 | 75.2 | 71.8 | 41.5 | 39.5 | 65.1 | 63 |
1 3/4 | 80.6 | 77.1 | 44.7 | 42.6 | 69.9 | 67.6 |
1 7/8 | 86.2 | 82.3 | 47.9 | 45.8 | 74.6 | 72.2 |
2 | 91.6 | 87.6 | 51.1 | 48.9 | 79.4 | 76.8 |
2 1/4 | 102.6 | 98.1 | 57.2 | 54.7 | 88.9 | 86.1 |
2 1/2 | 113.6 | 108.6 | 63.6 | 61 | 98.4 | 95.2 |
2 3/4 | 124.6 | 119.1 | 70.1 | 67.2 | 108 | 104.4 |
3 | 135.6 | 129.6 | 76.5 | 73.5 | 117.5 | 113.7 |