What Is Torque?

As Andy Dwyer might say, “I don’t know what torque is, and at this point I’m too afraid to ask.”

The word “torque” gets tossed around all the time on shop floors, but what is it?

Torque is the measurement of how much force you’ll need to rotate an object around an axis. You can calculate it by multiplying force times length:

Torque = Force x Length

For example, torque helps you use a wrench to loosen or tighten a nut, and the size of the wrench determines how much torque it can actually produce. A shorter wrench has a low torque and gives you less force to rotate the nut and loosen or tighten it. The longer wrench has a higher torque and gives you more force, making it much easier to rotate the nut.

Torque = Units of force (e.g. Newtons) x The length of the wrench

You’ll use less force with a longer wrench because increasing length increases torque. You’re traveling a longer distance and spreading the work out along a longer path.

Similarly, when riding a bike uphill, switching the bike to a low gear (high torque) makes it easier to move up the hill. This is because you’re using a physically larger gear on the wheel and, again, spreading the work out along a longer path.

This explains why riding in a low gear makes the bike travel slower. Spreading the force out over a longer distance (larger gear) means it takes longer for the gear and chain to rotate the wheel.

Horsepower vs. Torque

While torque meausures the amount of force an object produces, horsepower measures how quickly it can produce that force.

Horsepower = Torque / Time

Automakers calculate horsepower in cars by measuring how much power it would take for the car to move 550 pounds across one foot in one second.

Torque in Manufacturing

Manufacturers can use torque to run conveyor belts and other automation equipment. A high-torque motor on a conveyor belt means the belt moves with more force, making it easier to move heavy objects.

Shaft mount speed reducers like the ones from Baart Industrial Group’s Vortex VXT Series provide torque to drive conveyors and industrial automation equipment.

Torque is also the reason nuts, bolts, and other fasteners can hold materials together. If there’s not enough torque, the fasteners won’t be able to hold the materials together. Too much torque, and the fasteners can break from tension. This is why builders use torque wrenches, which apply a specific amount of torque chosen by the user.