Maker & Reference
Bolt Torque Calculator
Torque = K × diameter × clamp load. K factor depends on lubrication. Wrong torque snaps bolts or leaves joints loose.
Torque (ft-lb)
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- In-lb
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- N·m
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- Clamp load (lb)
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FAQ
Dry vs lubricated torque? +
Same clamp load needs ~30% less torque if you lube the threads. Always check what the spec was written for — over-torquing a lubed bolt stretches or snaps it.
How to tell bolt grade? +
Look at the head. Grade 5 has 3 radial lines. Grade 8 has 6 lines. Metric is stamped with numbers (8.8, 10.9, 12.9). No marks = Grade 2.