7/16" Bolt Torque
A 7/16" Grade 5 bolt with a coarse 7/16"-14 UNC thread needs about 48.4 ft·lb (65.6 N·m) when dry and 36.5 ft·lb (49.5 N·m) when oiled, tightened to 70% of yield (clamp force 30.4 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| Grade 2 | 18.9 kN4242 lbf | 30.0 ft·lb40.7 N·m | 22.6 ft·lb30.7 N·m | 15.3 ft·lb20.7 N·m |
| Grade 5 | 30.4 kN6843 lbf | 48.4 ft·lb65.6 N·m | 36.5 ft·lb49.5 N·m | 24.6 ft·lb33.4 N·m |
| Grade 8 | 43.0 kN9671 lbf | 68.4 ft·lb92.8 N·m | 51.6 ft·lb70.0 N·m | 34.8 ft·lb47.2 N·m |
| A307 | 12.0 kN2698 lbf | 19.1 ft·lb25.9 N·m | 14.4 ft·lb19.5 N·m | 9.70 ft·lb13.2 N·m |
| A574 | 49.6 kN11160 lbf | 79.0 ft·lb107.0 N·m | 59.5 ft·lb80.7 N·m | 40.1 ft·lb54.4 N·m |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| Grade 2 | 21.1 kN4737 lbf | 32.6 ft·lb44.2 N·m | 24.3 ft·lb32.9 N·m | 15.9 ft·lb21.5 N·m |
| Grade 5 | 34.0 kN7641 lbf | 52.6 ft·lb71.4 N·m | 39.1 ft·lb53.0 N·m | 25.6 ft·lb34.7 N·m |
| Grade 8 | 48.0 kN10799 lbf | 74.4 ft·lb100.8 N·m | 55.3 ft·lb75.0 N·m | 36.2 ft·lb49.1 N·m |
| A307 | 13.4 kN3013 lbf | 20.8 ft·lb28.1 N·m | 15.4 ft·lb20.9 N·m | 10.1 ft·lb13.7 N·m |
| A574 | 55.4 kN12463 lbf | 85.8 ft·lb116.4 N·m | 63.8 ft·lb86.5 N·m | 41.8 ft·lb56.7 N·m |
Torque for 7/16" hex head bolts and nuts, standard ISO/ASME heads on steel with a 11.9 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
7/16" thread and dimensions
- Coarse thread
- 7/16"-14 UNC — pitch 14 TPI
- Fine thread
- 7/16"-20 UNF — pitch 20 TPI
- Tensile stress area Aₛ
- 68.6 mm² (coarse), 76.6 mm² (fine)
- Pitch diameter d₂
- 9.934 mm
- Tap drill
- U (coarse), 25/64 (fine)
- Wrench size (hex head)
- 5/8"
- Clearance hole
- 11.9 mm
How the 7/16" 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 × 68.6 mm² = 30.4 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 30.4 kN × (0.16·1.81 + 0.58·0.15·9.93 + 0.15·13.89/2) mm = 65.6 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (13.89 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for a 7/16" Grade 5 bolt?
About 48.4 ft·lb (65.6 N·m) with dry threads, 36.5 ft·lb (49.5 N·m) with oiled threads and 24.6 ft·lb (33.4 N·m) with PTFE or moly paste, for a coarse 7/16"-14 UNC thread tightened to 70% of yield. The resulting clamp force is 30.4 kN.
What is the torque for a 7/16" Grade 8 bolt?
About 68.4 ft·lb (92.8 N·m) with dry threads, 51.6 ft·lb (70.0 N·m) with oiled threads and 34.8 ft·lb (47.2 N·m) with PTFE or moly paste, for a coarse 7/16"-14 UNC thread tightened to 70% of yield. The resulting clamp force is 43.0 kN.
What size wrench fits a 7/16" bolt?
A standard 7/16" hex head bolt or nut takes a 5/8" wrench or socket.
What drill size do I need to tap 7/16"?
Use a U drill for 7/16"-14 UNC and 25/64 for 7/16"-20 UNF.