Heavy Hex Nuts
Robust fastener with a thicker, wider hexagonal shape for high-stress applications.
Manufactured and stocked across ASTM A194 grades from 2H to 8MA, plain or coated.
Specifications & technical data.
Heavy hex nuts to ASME B18.2.2 — wider across the flats and thicker than a finished hex nut, in every A194 grade and the stainless and nickel alloys, machined or hot-forged in-house.
Download our heavy hex nut dimensioning table (PDF)
| Nominal Size | Width Across Flats, F | Width Across Corners (max), G | Thickness, H |
|---|---|---|---|
| 1/4" | 0.500 | 0.577 | 0.234 |
| 5/16" | 0.562 | 0.650 | 0.297 |
| 3/8" | 0.688 | 0.794 | 0.359 |
| 7/16" | 0.750 | 0.866 | 0.422 |
| 1/2" | 0.875 | 1.010 | 0.484 |
| 9/16" | 0.938 | 1.083 | 0.547 |
| 5/8" | 1.062 | 1.227 | 0.609 |
| 3/4" | 1.250 | 1.443 | 0.734 |
| 7/8" | 1.438 | 1.660 | 0.859 |
| 1" | 1.625 | 1.876 | 0.984 |
| 1-1/8" | 1.812 | 2.093 | 1.109 |
| 1-1/4" | 2.000 | 2.309 | 1.219 |
| 1-3/8" | 2.188 | 2.526 | 1.344 |
| 1-1/2" | 2.375 | 2.742 | 1.469 |
| 1-3/4" | 2.750 | 3.175 | 1.719 |
| 2" | 3.125 | 3.608 | 1.969 |
| 2-1/4" | 3.500 | 4.041 | 2.203 |
| 2-1/2" | 3.875 | 4.474 | 2.453 |
| 2-3/4" | 4.250 | 4.907 | 2.703 |
| 3" | 4.625 | 5.340 | 2.953 |
| 3-1/4" | 5.000 | 5.774 | 3.188 |
| 3-1/2" | 5.375 | 6.207 | 3.438 |
| 3-3/4" | 5.750 | 6.640 | 3.688 |
| 4" | 6.125 | 7.073 | 3.938 |
Per ASME B18.2.2 basic dimensions — confirm requirements with our estimating team.
Standards.
What are heavy hex nuts?
Heavy hex nuts carry a larger width across flats and a greater thickness than standard finished hex nuts of the same thread size — more thread engagement, more bearing area, more capacity. They are the standard mate for studbolts in flanged joints and for high-strength bolting everywhere.
- Wider and thicker than finished hex nuts — ASME B18.2.2 heavy pattern
- A194 grades 2H, 2HM, 7, 7M, 8 and stainless / nickel alloys
- Machined or hot-forged in-house, tapped to class 2B or 3B
- Oversize tapping for hot-dip galvanized assemblies
Heavy hex vs. finished hex nuts
A finished hex nut is the general-purpose pattern; the heavy hex is dimensionally bigger for the same thread — roughly an eighth of an inch more across the flats and a thicker body. High-strength and pressure-boundary bolting specifies heavy hex almost without exception, because the extra section develops the full strength of the stud.
Other names
- Heavy hexagon nuts
- 2H nuts
- A194 nuts
- Heavy nuts
- Stud nuts
Industries & applications
Oil & Gas
- Applications: flange assemblies with B7 / L7 studbolts, wellhead equipment
- Materials: A194 2H / 2HM / 7 / 7M, super duplex
Power Generation
- Applications: steam flanges, turbine bolting sets
- Materials: A194 4 / 7, A453 660 nuts, Inconel 718
Military & Marine
- Applications: shipboard and subsea bolting with full traceability
- Materials: Monel 400 / K500, 316L, Nitronic 60 (anti-galling)
Tips for purchasing
- Match the nut grade to the stud — 2H with B7, 7 or 7M with L7 / B7M, stainless with stainless; we certify the set together.
- Galvanized studs need oversize-tapped nuts — tell us the coating and we handle the fit.
- Anti-galling matters in stainless — consider Nitronic 60 or a coated thread.
- Proof-load testing and full material test reports available on request.
Materials.
Representative capabilities — every item is manufactured or certified to your specification. Confirm requirements with our estimating team.
