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. I have listed the Heavy hex nut dimensions as per ISO and UNC.

heavy hex nut dimensions

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

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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

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About Author

Varun Patel, B.E – Mechanical, PMP®

19+ years of experience in the oil and gas sector, specializing in project management, contracts, project control, project coordination, QA/QC and inspection of large-scale Greenfield and Brownfield Projects such as Refinery, Petrochemical, Wellhead production, and Process platform. Proven track record of delivering large-scale projects while ensuring adherence to safety and quality standards. Skilled in leading and mentoring cross-functional teams and resolving technical issues to achieve successful project outcomes.