Air Impact Wrench

Impact wrenches, also known simply air wrenches, pneumatic wrenches, torque wrenches or impactors, are one of the most useful workshop tools. Used extensively by mechanics, and also in industry, heavy duty construction, assembly lines etc, impact wrenches are essential for delivering high torque very quickly.

They work by spinning a mass known as a hammer and then suddenly applying that force to the drive shaft. This method means a superb power to weight ratio, and extremely fast and efficient work. Once the hammer has delivered the impact force the motor is then released to spin freely, this means there is very little reaction force meaning that they are easy to use, transferring little force to the operator, while applying high torque to the socket.

While electric and hydraulic versions are available, air impact wrenches are by far the most common. Using compresses air to drive a vane motor, they deliver extremely good power to weight ratios and are inexpensive.

Air impact wrenches are available for all standard socket sizes. Starting at 1/4” for light work, and increasing in increments up to 8” for heavy construction, there is an air impact wrench suitable for every task. The most common sizes are 1” and 2” wrenches used mostly in the automotive industry and garages. They are by far the most common of air tools found in a mechanics workshop.

Air impact wrenches are available in a number of different styles, from inline models which are held like a screwdriver, to pistol grip wrenches for 1/2” and above sockets. From 1” and above, D-handle models become more popular due to the increased forces being applied.

Modern air impact wrenches are low noise, low vibration and smaller units can often be used one-handed. Small, lightweight wrenches are available from manufacturers such as Matika, Sealey, Ingersoll and Draper, and allow even the home mechanic on a budget the advantages of a full workshop air wrench.

Air impact wrenches, while delivering the best power to weight ratio for the money, are still relatively expensive and require an air compressor. For the small home workshop, and small businesses requiring the use of an impact wrench, lightweight electric or even cordless impact wrenches are available.

No matter what scale of workshop you have, there is almost certainly an impact wrench suitable for your needs. If you're working on a very small scale or have very occasional need for an impactor then an electric unit will probably suffice. If however you'll be using it on a regular basis then a proper air impact wrench will be well worth the investment.