Torque: Nm to lb-ft
Industrial torque conversion for bolts, motors, and machinery.
How to convert Nm to lb-ft?
Torque is a measure of the rotational force applied to an object. In the International System (SI), the unit is the Newton-meter (Nm). In the United States and the United Kingdom, technical torque is often expressed in Foot-pounds (lb-ft).
[Image of torque force on a wrench]1 Nm = 0.73756 lb-ft
1 lb-ft = 1.35581 Nm
Standard Bolt Torque Table
Approximate torque values for standard metric bolts (Class 8.8) converted to imperial units:
| Bolt Size | Metric (Nm) | Imperial (lb-ft) |
|---|---|---|
| M8 Bolt | 25 Nm | 18.4 lb-ft |
| M10 Bolt | 50 Nm | 36.9 lb-ft |
| M12 Bolt | 85 Nm | 62.7 lb-ft |
| M16 Bolt | 210 Nm | 154.9 lb-ft |
| M20 Bolt | 410 Nm | 302.4 lb-ft |
Torque in Mechanical Engineering
Why accurate torque conversion is essential for reliability:
- Clamping Force: Proper bolt tightening ensures that joints remain secure under vibration. Using the wrong scale on a torque wrench can lead to stripped threads or loose parts.
- Motor Specifications: Gearbox and motor selection depends on the peak torque required to move a load. Most software calculates in Nm, but US motors often list specs in lb-ft.
- Automotive Tapping: Wheel lug nuts and engine internal components have very specific torque patterns that must be followed according to the manufacturer's scale.
FAQ: Understanding Torque Units
Is lb-ft the same as ft-lb?
Technically, lb-ft (Pound-foot) is the correct unit for torque (static force), while ft-lb (Foot-pound) is often used to describe work or energy. In most industrial workshops, however, they are used interchangeably.
How much is 100 Nm in lb-ft?
100 Newton-meters is equivalent to approximately 73.76 foot-pounds of torque.