Air Compressor Scout

Reviews and General Information
on Air Compressors and Air Tools

Impact Wrench Buying Guide

If you have ever held a tool in your hand, at some point you’ve probably come across a bolt that just won’t give because its plain stuck, rusty or both! This causes you to lose precious time and wear yourself out (as well as your tools). Luckily, it’s possible to take advantage of an impact wrench which makes the removal of a stubborn bolt a total breeze.

Of course, you can use a tool like this to secure them in place too. Whether you’re a hobbyist, an advanced DIY enthusiast, or a professional you can complete your work much more efficiently with an impact wrench. With this in mind I have prepared the impact wrench buying guide below (just for you).

How It Works

Impact wrenches come in many different shapes and sizes. Some are designed to look like really large screwdrivers, while others are made to look like pistols. Regardless of the shape and size, the way they work is the same.

On the inside of every impact wrench is a rotating mass. The motor builds up energy through the rotation of that mass, and pushes it into an anvil that is located at the end. This creates a massive amount of torque which no human can produce. The mass which usually resembles a hammer goes on to rotate so the operator only feels a small fraction of the impact.

In addition to generating immense torque, impact wrenches are much more precise than human beings which makes them ideal for numerous applications. It is far safer to use this power tool for securing bolts on car wheels, or when working on construction sites. Even though all impact wrenches function in the same way, they do differ from one another in terms of features such as power source, shape, socket size and the amount of torque. Below, I look at each of these separately.

Power Source

Based on the kind of power source they use, impact wrenches are placed in three separate categories: Compressed air, electricity, and those powered by hydraulics. The first two types are more widespread, especially among contractors and car mechanics as well as enthusiasts while the hydraulic impact wrenches are mainly used in an industrial environment.

Impact wrenches which use compressed air are very common in car repair shops. Usually, they have an air tank fitted on one end which provides them with compressed air. Compressed air is extremely powerful, and connecting it to an impact wrench is a natural fit. Another advantage of these wrenches is they are light since they don’t have a motor or batteries to generate power. On the other hand, you need to have a full air tank at hand.

The electric designs are not quite as powerful as the compressed air type, but they are not far behind either. These come in very handy around your home where you most likely won’t have an air tank lying around. Now, when it comes to electric impact wrenches you have a choice between a wrench that plugs into a standard electrical socket, and a battery-powered unit. Battery operated wrenches tend to be heavier because of the extra weight batteries add, but you get total portability with them.

On the opposite end, corded impact wrenches are much lighter, and provide you with a constant flow of power, but they are limited by the length of the cord as well as the location of power sockets.
Hydraulic motors provide power to hydraulic impact wrenches. You won’t find these in anyone’s home, or at your local auto shop because their power far exceeds the requirement of most professionals. They are used on large construction sites as well as in factories where a massive amount of torque is required.

Shape and Socket Size

Based on the shape of the wrench, impact wrenches can be divided into two basic types: Inline and pistol.
Inline wrenches resemble an oversized screwdriver, with the hammer and the anvil located in front of the grip. Pistol type wrenches on the other hand, have the hammer and anvil located above the grip. When it comes to socket size, impact wrenches have plenty available which can fit onto pretty much any nut or bolt. In terms of size, sockets can be as large as a couple of inches, but are generally smaller than one inch.


Torque defines every impact wrench and each one has a specific maximum. However, they are not limited to that one amount. Most wrenches allow you to choose between multiple torque settings which lets you adjust the amount of torque according to the requirements of the job. Just one word of advice here, do make sure you always use the right amount of torque or you could end up in trouble(an under tightened bolt can have devastating consequences).


Now that you know how impact wrenches work, and some of their basic features feel free to take a look at my reviews on the best ones I have come across by clicking here.

Back to Top