The Wrencher

Just about every mechanic out there should have an impact wrench in their stable of tools. It makes peeling off bolts about as easy as possible, especially when you consider how much fatigue can set in on your arm and joints if you’re doing it over and over throughout the day with a conventional wrench instead. However, while choosing an impact wrench makes a lot of sense, you need to make sure you pick the right one. Two of the most popular options are air and pneumatic options.

Pneumatic Impact Wrenches

This is the kind of impact wrench most people are familiar with. They are powered either by condensed gas like Co2 or otherwise just air. By putting these gases under pressure, they can exert huge amounts of force when someone uses their impact wrench to release it.

These types of wrenches are designed with drive sizes of 0.75-inch, 0.5-inch, 0.375-inch, 0.25 inch or a full inch. No matter what size you choose, however, large compressors are needed in order to make an impact wrench work as desired. That being said, there is a lot of power to be gained with a sizable compressor on your side. A one-inch drive can deliver up to 3,000 feet per pound of torque.

Most pneumatic wrenches come with the typical pistol grip, but these days, you have more and more options to choose from.

The main disadvantage to this kind of impact wrench is simply how much power you have to control in order to use it. There are no variable-speed triggers, for one thing and power is difficult to adjust. So if you only need a little bit of power—say to remove a tiny screw—this device will be too much.

Air Impact Wrenches

While air impact wrenches definitely fall under the umbrella of pneumatic tools, as the name suggests, these only focus on the types of wrenches that use air—as opposed to those that use CO2 or other gases—for their power.

The main advantage involved here is simply that common air is so much cheaper. So you’ll find it less expensive to operate your wrench. If you’re operating a garage or auto body shop that uses a number of different wrenches, this can be a real advantage.

One of its big disadvantages, though, as that this type of “fuel” doesn’t deliver as much energy as condensed CO2 can. So there may be some jobs where your pneumatic wrench just isn’t up to the task.

However, at the same time, this fills in nicely for the disadvantage we covered with conventional pneumatic wrenches. The lack of so much power means it’s also easier for you to choose just enough in order to address jobs without breaking screws off or causing other problems.

At the end of the day, many impact wrenches can handle either “fuel” source. So you can disconnect from one and connect the other as necessary. Otherwise, the types of jobs you predominantly handle should help you determine which one is best for you.