How do I convert Nm to ft-lb?

To convert Newton-meters (Nm) to foot-pounds (ft-lb), multiply by 0.7376. For example, 100 Nm × 0.7376 = 73.76 ft-lb. Conversely, to convert ft-lb to Nm, multiply by 1.3558. Our calculator performs these conversions instantly.

What is the formula for torque to horsepower?

Horsepower = (Torque × RPM) / 5252, where torque is in foot-pounds. For metric: kW = (Torque in Nm × RPM) / 9549. This relationship shows that horsepower is torque multiplied by rotational speed.

What torque should I use for lug nuts?

Lug nut torque varies by vehicle: typically 80-100 ft-lb (108-135 Nm) for passenger cars, 90-120 ft-lb (122-163 Nm) for trucks/SUVs, and 140+ ft-lb (190+ Nm) for heavy-duty applications. Always check your vehicle's manual for exact specifications.

How does a torque wrench extension affect torque?

When using an extension perpendicular to the torque wrench (like a crow's foot), actual torque = Set torque × (L / (L + E)), where L is wrench length and E is extension length. Extensions in-line with the wrench don't affect the torque reading.

What is torque angle tightening?

Torque angle (or torque-to-yield) tightening involves first tightening to a specified torque, then rotating an additional specific angle (e.g., 90°). This method provides more consistent clamping force and is common for critical fasteners like head bolts.

What is the difference between Grade 5 and Grade 8 bolts?

Grade 8 bolts are stronger than Grade 5. Grade 5 has a tensile strength of 120,000 PSI (3 radial lines on head), while Grade 8 has 150,000 PSI (6 radial lines). Grade 8 bolts require approximately 20% more torque for the same size.

What is the metric equivalent of Grade 8 bolts?

Class 10.9 metric bolts are roughly equivalent to SAE Grade 8. Class 8.8 is similar to Grade 5. Class 12.9 exceeds Grade 8 strength. These classes indicate tensile strength: 8.8 = 800 MPa, 10.9 = 1040 MPa, 12.9 = 1220 MPa.

Should I torque bolts dry or lubricated?

Most torque specifications assume clean, dry threads unless stated otherwise. Lubricated threads reduce friction and can result in over-tightening if using dry torque specs. Reduce torque by 15-25% for oiled threads, or 50% for anti-seize compounds.

Why is proper torque important?

Proper torque ensures: (1) Adequate clamping force to prevent loosening, (2) Prevention of fastener/thread damage from over-tightening, (3) Even load distribution, (4) Proper gasket sealing, (5) Reliable joint integrity under stress and vibration.

How do I use a torque wrench correctly?

Set the desired torque value, apply slow steady pressure perpendicular to the handle, stop when you hear/feel the click (click-type) or reach the indicated value (dial/digital). Never use extensions on the handle, and store click-type wrenches at lowest setting.

How do I convert Nm to ft-lb?

To convert Newton-meters (Nm) to foot-pounds (ft-lb), multiply by 0.7376. For example, 100 Nm × 0.7376 = 73.76 ft-lb. Conversely, to convert ft-lb to Nm, multiply by 1.3558. Our calculator performs these conversions instantly with high precision.

What is the formula for torque to horsepower?

Horsepower = (Torque × RPM) / 5252, where torque is in foot-pounds. For metric: kW = (Torque in Nm × RPM) / 9549. This relationship shows that horsepower is torque multiplied by rotational speed, divided by a constant.

What torque should I use for lug nuts?

Lug nut torque varies by vehicle: typically 80-100 ft-lb (108-135 Nm) for compact cars, 90-120 ft-lb (122-163 Nm) for sedans with alloy wheels, and 140+ ft-lb (190+ Nm) for trucks/SUVs. Always check your vehicle's owner manual for exact specifications.

How does a torque wrench extension affect torque?

When using an extension perpendicular to the torque wrench (like a crow's foot), actual torque = Set torque × (L / (L + E)), where L is wrench length and E is extension length. Extensions in-line with the wrench handle don't affect the torque reading.

What is torque angle tightening?

Torque angle (or torque-to-yield) tightening involves first tightening to a specified torque, then rotating an additional specific angle (e.g., 90°). This method provides more consistent clamping force and is common for critical fasteners like cylinder head bolts.

What is the difference between Grade 5 and Grade 8 bolts?

Grade 8 bolts are stronger than Grade 5. Grade 5 has a tensile strength of 120,000 PSI (identified by 3 radial lines on head), while Grade 8 has 150,000 PSI (6 radial lines). Grade 8 bolts require approximately 20% more torque for the same size.

What is the metric equivalent of Grade 8 bolts?

Class 10.9 metric bolts are roughly equivalent to SAE Grade 8. Class 8.8 is similar to Grade 5. Class 12.9 exceeds Grade 8 strength. The numbers indicate tensile strength: 8.8 = 800 MPa, 10.9 = 1040 MPa, 12.9 = 1220 MPa.

Should I torque bolts dry or lubricated?

Most torque specifications assume clean, dry threads unless stated otherwise. Lubricated threads reduce friction and can result in over-tightening if using dry torque specs. Reduce torque by 15-25% for oiled threads, or about 50% for anti-seize compounds.

Why is proper torque important?

Proper torque ensures: (1) Adequate clamping force to prevent loosening, (2) Prevention of fastener/thread damage from over-tightening, (3) Even load distribution across the joint, (4) Proper gasket sealing, (5) Reliable joint integrity under stress and vibration.

How do I use a torque wrench correctly?

Set the desired torque value, apply slow steady pressure perpendicular to the handle, stop when you hear/feel the click (click-type) or reach the indicated value (dial/digital). Never use extensions on the handle, and store click-type wrenches at their lowest setting.

Torque Conversion Calculator

Professional torque converter with 12+ units including Nm, ft-lb, in-lb, and kg-cm. Features torque-to-horsepower calculator, bolt specifications, and wrench extension calculator.

Torque Converter

Enter Torque Value

Select Unit

Conversion Results

Newton-meters

—

Foot-pounds

—

ft·lb

Inch-pounds

—

in·lb

Kilogram-force centimeters

—

kgf·cm

Kilonewton-meters

— kNm

Millinewton-meters

— mNm

Kilogram-force meters

— kgf·m

Newton-centimeters

— N·cm

Newton-millimeters

— N·mm

Inch-ounces

— in·oz

Foot-ounces

— ft·oz

Dyne-centimeters

— dyn·cm

Gram-force centimeters

— gf·cm

Quick Reference

1 Nm =

0.7376 ft·lb

1 ft·lb =

1.3558 Nm

1 Nm =

8.8507 in·lb

1 kgf·m =

9.8066 Nm

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“Essential tool for my auto shop. The bolt torque database saves us time looking up specs, and the extension calculator prevents over-torquing with crow's feet.”

Carlos M.

Master Mechanic

“The torque-to-horsepower calculator is perfect for engine builds. I can instantly see how modifications affect power output at different RPMs.”

Steve R.

Engine Builder

“Finally, a torque converter that includes all the units I need. The metric bolt specifications with class ratings are exactly what I use for precision work.”

Hans K.

Industrial Engineer

“As a DIY enthusiast, this tool helped me properly torque everything during my engine rebuild. The automotive specs section is incredibly useful.”

Mike T.

DIY Mechanic

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