#10 Screw Torque
A #10 A574 screw with a coarse 10-24 UNC thread needs about 73.3 in·lb (8.28 N·m) when dry and 56.0 in·lb (6.32 N·m) when oiled, tightened to 70% of yield (clamp force 8.19 kN).
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| A574 | 8.19 kN1840 lbf | 73.3 in·lb8.28 N·m | 56.0 in·lb6.32 N·m | 38.6 in·lb4.36 N·m |
| Grade | Clamp forcepreload | Dryμ 0.15 | Oiledμ 0.11 | PTFE / moly pasteμ 0.06 |
|---|---|---|---|---|
| A574 | 9.34 kN2099 lbf | 81.3 in·lb9.19 N·m | 61.2 in·lb6.91 N·m | 41.1 in·lb4.64 N·m |
Torque for #10 screws with a cap-screw head (head size estimated) on steel with a 5.6 mm clearance hole. Friction μ applies to both the threads and the bearing face. Always follow the manufacturer's value where one exists.
#10 thread and dimensions
- Coarse thread
- 10-24 UNC — pitch 24 TPI
- Fine thread
- 10-32 UNF — pitch 32 TPI
- Tensile stress area Aₛ
- 11.3 mm² (coarse), 12.9 mm² (fine)
- Pitch diameter d₂
- 4.139 mm
- Tap drill
- #25 (coarse), #21 (fine)
- Clearance hole
- 5.6 mm
How the #10 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% × 1034 MPa × 11.3 mm² = 8.19 kN
T = F × (0.16·P + 0.58·μ·d₂ + μ·Dₖₘ/2)
T = 8.19 kN × (0.16·1.06 + 0.58·0.15·4.14 + 0.15·6.67/2) mm = 8.28 N·m
Here d₂ is the pitch diameter and Dₖₘ the effective bearing diameter of the head (6.67 mm). Change the grade, lubrication or preload in the calculator below.
Frequently asked questions
What is the torque for a #10 A574 screw?
About 73.3 in·lb (8.28 N·m) with dry threads, 56.0 in·lb (6.32 N·m) with oiled threads and 38.6 in·lb (4.36 N·m) with PTFE or moly paste, for a coarse 10-24 UNC thread tightened to 70% of yield. The resulting clamp force is 8.19 kN.
What drill size do I need to tap #10?
Use a #25 drill for 10-24 UNC and #21 for 10-32 UNF.