This page has the Nut and Wrench Sizes (PB-TD-206) as page tables, with a printable PDF sheet below. It lists heavy hex nut dimensions, wrench sizes and across-corners clearance for flange bolting. Values are for reference; confirm against the current edition of the governing standard. Send us your print for a quote or call (281) 581-0176.
Related: Torque Reference Charts · All technical docs
Nut and Wrench Sizes
Per ASME B18.2.2. All dimensions in inches. On a phone, swipe the table sideways to see every column.
| Nominal Size | Heavy Hex Nut (ASME B18.2.2) | Wrench / Socket Size | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Width Across Flats | Width Across Corners | Thickness | Heavy Hex Nut and Bolt | Finished Hex Nut | ||||||
| Basic | Min. | Max. | Min. | Max. | Basic | Min. | Max. | |||
| 1/4 | 1/2 | 0.488 | 0.500 | 0.556 | 0.577 | 15/64 | 0.218 | 0.250 | 1/2 | 7/16 |
| 5/16 | 19/32 | 0.546 | 0.562 | 0.622 | 0.650 | 19/64 | 0.280 | 0.314 | 19/32 | 1/2 |
| 3/8 | 11/16 | 0.669 | 0.688 | 0.763 | 0.794 | 23/64 | 0.341 | 0.377 | 11/16 | 9/16 |
| 7/16 | 25/32 | 0.728 | 0.750 | 0.830 | 0.866 | 27/64 | 0.403 | 0.441 | 25/32 | 11/16 |
| 1/2 | 7/8 | 0.850 | 0.875 | 0.969 | 1.010 | 31/64 | 0.464 | 0.504 | 7/8 | 3/4 |
| 9/16 | 31/32 | 0.909 | 0.938 | 1.037 | 1.083 | 35/64 | 0.526 | 0.568 | 31/32 | 7/8 |
| 5/8 | 1-1/16 | 1.031 | 1.062 | 1.175 | 1.227 | 39/64 | 0.587 | 0.631 | 1-1/16 | 15/16 |
| 3/4 | 1-1/4 | 1.212 | 1.250 | 1.382 | 1.443 | 47/64 | 0.710 | 0.758 | 1-1/4 | 1-1/8 |
| 7/8 | 1-7/16 | 1.394 | 1.438 | 1.589 | 1.660 | 55/64 | 0.833 | 0.885 | 1-7/16 | 1-5/16 |
| 1 | 1-5/8 | 1.575 | 1.625 | 1.796 | 1.876 | 63/64 | 0.956 | 1.012 | 1-5/8 | 1-1/2 |
| 1-1/8 | 1-13/16 | 1.756 | 1.812 | 2.002 | 2.093 | 1-7/64 | 1.079 | 1.139 | 1-13/16 | 1-11/16 |
| 1-1/4 | 2 | 1.938 | 2.000 | 2.209 | 2.309 | 1-7/32 | 1.187 | 1.251 | 2 | 1-7/8 |
| 1-3/8 | 2-3/16 | 2.119 | 2.188 | 2.416 | 2.526 | 1-11/32 | 1.310 | 1.378 | 2-3/16 | 2-1/16 |
| 1-1/2 | 2-3/8 | 2.300 | 2.375 | 2.622 | 2.742 | 1-15/32 | 1.433 | 1.505 | 2-3/8 | 2-1/4 |
| 1-5/8 | 2-9/16 | 2.481 | 2.562 | 2.828 | 2.959 | 1-19/32 | 1.556 | 1.632 | 2-9/16 | — |
| 1-3/4 | 2-3/4 | 2.662 | 2.750 | 3.035 | 3.175 | 1-23/32 | 1.679 | 1.759 | 2-3/4 | — |
| 1-7/8 | 2-15/16 | 2.844 | 2.938 | 3.242 | 3.392 | 1-27/32 | 1.802 | 1.886 | 2-15/16 | — |
| 2 | 3-1/8 | 3.025 | 3.125 | 3.449 | 3.608 | 1-31/32 | 1.925 | 2.013 | 3-1/8 | — |
| 2-1/4 | 3-1/2 | 3.388 | 3.500 | 3.862 | 4.041 | 2-13/64 | 2.155 | 2.251 | 3-1/2 | — |
| 2-1/2 | 3-7/8 | 3.750 | 3.875 | 4.275 | 4.474 | 2-29/64 | 2.401 | 2.505 | 3-7/8 | — |
| 2-3/4 | 4-1/4 | 4.112 | 4.250 | 4.688 | 4.907 | 2-45/64 | 2.647 | 2.759 | 4-1/4 | — |
| 3 | 4-5/8 | 4.475 | 4.625 | 5.102 | 5.340 | 2-61/64 | 2.893 | 3.013 | 4-5/8 | — |
| 3-1/4 | 5 | 4.838 | 5.000 | 5.515 | 5.774 | 3-3/16 | 3.124 | 3.252 | 5 | — |
| 3-1/2 | 5-3/8 | 5.200 | 5.375 | 5.928 | 6.207 | 3-7/16 | 3.370 | 3.506 | 5-3/8 | — |
| 3-3/4 | 5-3/4 | 5.562 | 5.750 | 6.341 | 6.640 | 3-11/16 | 3.616 | 3.760 | 5-3/4 | — |
| 4 | 6-1/8 | 5.925 | 6.125 | 6.755 | 7.073 | 3-15/16 | 3.862 | 4.014 | 6-1/8 | — |
Which Fastener Fits This Wrench? (nominal size, in.)
| Wrench Size | Heavy Hex Nut or Bolt | Finished Hex Nut | Hex Cap Screw | Wrench Size | Heavy Hex Nut or Bolt | Finished Hex Nut | Hex Cap Screw |
|---|---|---|---|---|---|---|---|
| 7/16 | — | 1/4 | 1/4 | 1-13/16 | 1-1/8 | — | — |
| 1/2 | 1/4 | 5/16 | 5/16 | 1-7/8 | — | 1-1/4 | 1-1/4 |
| 9/16 | — | 3/8 | 3/8 | 2 | 1-1/4 | — | — |
| 19/32 | 5/16 | — | — | 2-1/16 | — | 1-3/8 | 1-3/8 |
| 5/8 | — | — | 7/16 | 2-3/16 | 1-3/8 | — | — |
| 11/16 | 3/8 | 7/16 | — | 2-1/4 | — | 1-1/2 | 1-1/2 |
| 3/4 | — | 1/2 | 1/2 | 2-3/8 | 1-1/2 | — | — |
| 25/32 | 7/16 | — | — | 2-9/16 | 1-5/8 | — | — |
| 13/16 | — | — | 9/16 | 2-3/4 | 1-3/4 | — | — |
| 7/8 | 1/2 | 9/16 | — | 2-15/16 | 1-7/8 | — | — |
| 15/16 | — | 5/8 | 5/8 | 3-1/8 | 2 | — | — |
| 31/32 | 9/16 | — | — | 3-1/2 | 2-1/4 | — | — |
| 1-1/16 | 5/8 | — | — | 3-7/8 | 2-1/2 | — | — |
| 1-1/8 | — | 3/4 | 3/4 | 4-1/4 | 2-3/4 | — | — |
| 1-1/4 | 3/4 | — | — | 4-5/8 | 3 | — | — |
| 1-5/16 | — | 7/8 | 7/8 | 5 | 3-1/4 | — | — |
| 1-7/16 | 7/8 | — | — | 5-3/8 | 3-1/2 | — | — |
| 1-1/2 | — | 1 | 1 | 5-3/4 | 3-3/4 | — | — |
| 1-5/8 | 1 | — | — | 6-1/8 | 4 | — | — |
| 1-11/16 | — | 1-1/8 | 1-1/8 |
- All dimensions are in inches. Heavy hex nut width across flats = 1.5 D + 1/8 in.; heavy hex nut thickness is approximately equal to D − 1/64 in.
- Wrench size is the basic width across flats. Use six-point sockets of the correct size; avoid twelve-point sockets on heavy hex nuts at high torque.
- Heavy hex bolts use the same wrench size as heavy hex nuts of the same diameter. Finished hex nuts (sizes to 1-1/2 in.) use the smaller size shown; hex cap screws match them except 7/16 (5/8 in.) and 9/16 (13/16 in.).
- Width across corners is the maximum swing diameter; use it to check clearance to flange hubs, adjacent nuts and fittings.
- Symbols: D = nominal diameter; F = width across flats; G = width across corners; H = nut thickness.
- Reference data only. Verify against the current edition of ASME B18.2.2 before use. Printable sheet: PB-TD-206.
About the Nut and Wrench Sizes chart
This sheet lists heavy hex nut dimensions to ASME B18.2.2, with the wrench or socket size for heavy hex nuts, finished hex nuts and hex cap screws. A second table shows which fasteners fit a given wrench, and the notes cover tool clearance for sockets, hydraulic torque wrenches and tensioners.
How to read the chart
- F: Width across flats. The wrench size; for heavy hex, 1.5D + 1/8 inch.
- G: Width across corners. Swing diameter for clearance checks.
- H: Nut thickness. About D minus 1/64 inch for heavy hex.
- Finished hex: Smaller wrench. For sizes to 1-1/2 inch.
- Cap screw exceptions: 7/16 and 9/16. Use 5/8 and 13/16 inch wrenches.
Ordering from Patriot Bolt
Patriot Bolt manufactures stud bolts, heavy hex nuts and special flange bolting from certified round bar in B7, B7M, L7, B16, stainless and nickel grades, with coatings on request. Mill test reports come with every order.
Common questions
Should I use 12-point sockets on heavy hex nuts?
Avoid them at high torque. Six-point sockets grip the flats better.
How much clearance does a tensioner need?
The bridge OD must clear the flange hub, and the stud must project at least one diameter above the nut.
See also: Heavy Hex Nuts chart · Nuts · Stud Bolts · Request a quote