9/16" Bolt Torque
A 9/16" Grade 5 bolt with a coarse 9/16"-12 UNC thread needs about 106.8 ft·lb (144.8 N·m) when dry and 80.1 ft·lb (108.7 N·m) when oiled, tightened to 70% of yield (clamp force 52.1 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| Grade 2 | 32.3 kN7260 lbf | 66.2 ft·lb89.7 N·m | 49.7 ft·lb67.4 N·m | 33.2 ft·lb45.0 N·m |
| Grade 5 | 52.1 kN11711 lbf | 106.8 ft·lb144.8 N·m | 80.1 ft·lb108.7 N·m | 53.5 ft·lb72.5 N·m |
| Grade 8 | 73.6 kN16551 lbf | 150.9 ft·lb204.6 N·m | 113.3 ft·lb153.6 N·m | 75.6 ft·lb102.5 N·m |
| A307 | 20.5 kN4618 lbf | 42.1 ft·lb57.1 N·m | 31.6 ft·lb42.8 N·m | 21.1 ft·lb28.6 N·m |
| A325 | 52.1 kN11711 lbf | 106.8 ft·lb144.8 N·m | 80.1 ft·lb108.7 N·m | 53.5 ft·lb72.5 N·m |
| A490 | 73.6 kN16551 lbf | 150.9 ft·lb204.6 N·m | 113.3 ft·lb153.6 N·m | 75.6 ft·lb102.5 N·m |
| A574 | 85.0 kN19100 lbf | 174.1 ft·lb236.1 N·m | 130.7 ft·lb177.2 N·m | 87.3 ft·lb118.3 N·m |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| Grade 2 | 36.0 kN8099 lbf | 71.9 ft·lb97.5 N·m | 53.2 ft·lb72.1 N·m | 34.4 ft·lb46.7 N·m |
| Grade 5 | 58.1 kN13065 lbf | 116.0 ft·lb157.2 N·m | 85.8 ft·lb116.3 N·m | 55.6 ft·lb75.3 N·m |
| Grade 8 | 82.1 kN18465 lbf | 163.9 ft·lb222.2 N·m | 121.2 ft·lb164.3 N·m | 78.5 ft·lb106.5 N·m |
| A307 | 22.9 kN5152 lbf | 45.7 ft·lb62.0 N·m | 33.8 ft·lb45.9 N·m | 21.9 ft·lb29.7 N·m |
| A325 | 58.1 kN13065 lbf | 116.0 ft·lb157.2 N·m | 85.8 ft·lb116.3 N·m | 55.6 ft·lb75.3 N·m |
| A490 | 82.1 kN18465 lbf | 163.9 ft·lb222.2 N·m | 121.2 ft·lb164.3 N·m | 78.5 ft·lb106.5 N·m |
| A574 | 94.8 kN21309 lbf | 189.1 ft·lb256.4 N·m | 139.9 ft·lb189.6 N·m | 90.6 ft·lb122.9 N·m |
Torque for 9/16" hex head bolts and nuts, standard ISO/ASME heads on steel with a 15.9 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
9/16" thread and dimensions
- Coarse thread
- 9/16"-12 UNC — pitch 12 TPI
- Fine thread
- 9/16"-18 UNF — pitch 18 TPI
- Tensile stress area Aₛ
- 117.4 mm² (coarse), 131.0 mm² (fine)
- Pitch diameter d₂
- 12.913 mm
- Tap drill
- 31/64 (coarse), 33/64 (fine)
- Wrench size (hex head)
- 13/16"
- Clearance hole
- 15.9 mm
How the 9/16" torque is calculated
Preload is 70% of the bolt's yield strength times its tensile stress area. Torque then follows the ISO 16047 / VDI 2230 formula, which splits it into thread pitch, thread friction and friction under the head:
F = 70% × 634 MPa × 117.4 mm² = 52.1 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 52.1 kN × (0.16·2.12 + 0.58·0.15·12.91 + 0.15·18.26/2) mm = 144.8 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (18.26 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for a 9/16" Grade 5 bolt?
About 106.8 ft·lb (144.8 N·m) with dry threads, 80.1 ft·lb (108.7 N·m) with oiled threads and 53.5 ft·lb (72.5 N·m) with PTFE or moly paste, for a coarse 9/16"-12 UNC thread tightened to 70% of yield. The resulting clamp force is 52.1 kN.
What is the torque for a 9/16" Grade 8 bolt?
About 150.9 ft·lb (204.6 N·m) with dry threads, 113.3 ft·lb (153.6 N·m) with oiled threads and 75.6 ft·lb (102.5 N·m) with PTFE or moly paste, for a coarse 9/16"-12 UNC thread tightened to 70% of yield. The resulting clamp force is 73.6 kN.
What size wrench fits a 9/16" bolt?
A standard 9/16" hex head bolt or nut takes a 13/16" wrench or socket.
What drill size do I need to tap 9/16"?
Use a 31/64 drill for 9/16"-12 UNC and 33/64 for 9/16"-18 UNF.