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What is a Torque Wrench?

The bridge you passed over or under on the way to work. The pipeline that brought the gas to your car. The power plant that’s creating the electricity you need to read this article.

All of these things have one thing in common: they rely on torque wrenches. But what is a torque wrench? Let’s take a look.

What is a torque wrench?

This year marks the 100th anniversary of the torque wrench, invented in 1918 by Conrad Bahr of the New York City water department.

Bahr was looking for a way to keep from overtightening the bolts on water main and pipe repairs, and the torque wrench provided him with a tool that could provide a specific level of torque to a fastener.

Torque wrenches are used in applications where the tightness of a fastener is critical, allowing users to measure torque so it can match the specifications of the job.

What is a torque wrench used for?

Calibrated industrial torque wrenches are used on large nuts and bolts used on wind turbines, petro-chemical plants, heavy manufacturing, and – as we indicated above — oil pipelines, bridge construction and power plants.

But not every torque wrench will work for every job. Let’s look at three of the chief torque wrench varieties – hydraulic, electric and pneumatic – and when they should be used:

1. Hydraulic torque wrenches

Hydraulic torque WrenchHydraulic torque wrenches are operated by a pump that’s driven by either electric or pneumatic power. They are industrial strength wrenches that can exert a strong amount of torque to a large bolt head.

With pneumatic and electric wrenches, the power source is part of the tool. But with hydraulic wrenches, the power source is at the pump, so the wrench itself is able to fit into a much tighter space, making them a good choice for power plants and steel mills or any place where you need a tool that is small and versatile.


2. Pneumatic torque wrenches

These wrenches are known for their durability. As Maxpro President Tom Macey put it when we wrote about pneumatic torque wrenches two years ago, workers could “drop it off a bridge and pick it up and start working again.”

And because they use pneumatic power, they’re a good choice for jobs where flammable liquids and gases might be in play, such as oil/gas pipelines or mines.

3. Electric torque wrenches

PaddedImage400400FFFFFF-E-RAD-7500 2-1Electric torque wrenches are more accurate than their pneumatic counterparts, with an accuracy range of plus or minus three percent.

And because you can plug them in, they’ll operate any place there’s a power source. And they make very little noise. They may not be as speedy as pneumatic wrenches, but they are lightweight, safe and powerful, used on wind turbines, nuclear plants and for military applications.

Whether your job requires an electric, hydraulic or pneumatic torque wrench, Maxpro has you covered. We not only sell top-quality wrenches from the RAD company, we also calibrate them at our state-of-the-art, A2LA-accredited lab.

Contact us today to learn how we can help you complete your next project.

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