How Impact Wrench Work

By Richard S. Clark | Last Updated: July 24, 2022

Understanding how an impact wrench works are complementary to using it with ease. There are different types of wrenches. For beginners, it might seem too complicated to use or even to operate one.

An impact wrench has several uses. You can find it in car garages, building sites, or even in carpentry sites. It also does several heavy-duty works more than a manual wrench.

Impact wrenches make the work more easy and fast. You can use it to tighten or remove bolts that are difficult to turn with the manual one.

In this article, I will show you how this tool works. I will also point out the merits and demerits of the same.

What are the different types of impact wrenches?

They are of two types, namely:

  1. Air impact, and
  2. Electric impact coded wrench.

Each of the two functions in an almost similar manner, but the difference is in the application that distinguishes them.

How does a coded electric impact wrench work?

As the name suggests, this type of wrench uses electric power to run its motors. The tool features a unique characteristic that is known as the impact function. It provides a lot of heavy bursts that are rotational. They are inside the wrench.

When you turn the machine on, it transfers the bursts to the drill bit. In turn, the impact moves to the bolts and nuts. The effect is that the bolts can either screw or unscrew.

In the machine, there is an anvil and a hammer mechanism. When the anvil and or the output shaft faces resistance, the impact functions activate. The hammer then slips from the pin and rotates faster and in a circular motion.

As the speed and energy increase, it comes into contact with the anvil and transfers the energy in a short burst. The process will repeat if the mechanism faces resistance.

What are the advantages of an electric impact wrench?

  • It offers variable speed options, meaning that you can adjust the torque’s settings with ease.
  • They work well in constricted, tight, or even narrow spaces.
  • Removes bolts and nuts that are otherwise difficult to remove with air impact wrenches and manual wrenches.
  • You can charge the mechanism and use it without connecting to a source of power.
  • It hastens the work and improves the performance and output of the user.

How does an air impact wrench work?

It works by applying a rotating torque or energy to the target and firing the same in short bursts. The rotating torque comes from the air at very high pressure.

Such kinds of wrenches work well where there is a constant and continuous supply of air. The adapter powers the airflow that then forces it through a tiny hole. It then comes into contact with a cylinder that has several equally-shaped blades. That is the rotor.

The air that drives the mechanism causes the rotor to spin, and that is what creates the rotational torque or energy. In the end, this torque or force passes to the bolt or nut.

The air impact wrench has a spline in which the hammer mechanism makes the hammer move together with the rotor cylinder. It makes it gain a lot of rotational energy or torque. The handle pulls the hammer back and pushes it forth again, and it presses the trigger. The mass then gains speed, and the bolt either screws or unscrews.

What are the advantages of an air impact wrench?

  • It is cheaper than any other type of impact wrench. That is to say, a lot of people can afford to own one.
  • They have a longer useful life, meaning that their life expectancy is high. You will gain value for your money.
  • It does not overheat because the air that runs the system also acts as a coolant. You can, therefore, do your work with a lot of peace of mind.
  • They make the task easy, and it is cheap to maintain. You only need a consistent supply of air to run the system, unlike the electric one that comes with high power bills!
  • It is easy to operate or to use. Should you face difficulty while using it, then refer to the user manual that comes with the wrench.

Which one is better between an electric wrench and an air wrench?

The two machines are best for the work, depending on their area of application. You can use any of them to screw or unscrew the bolt or a nut.

What are the procedures to follow before using an impact wrench?

If you are new to impact wrenches, then you should first learn how to use them. You can either get a trainer or even refer to the user manual that comes with the tool when buying.

The next step is to assemble it so that it can function as expected.

Put on the protective gear or clothing before starting the machine. Here, you would need to protect the eyes and the hands by wearing gloves.

Start the wrench and let it run for between thirty seconds to one minute. That is to allow for the mechanism to absorb the oil before you use it.

You are now ready to use your impact wrench. Please observe all the safety protocols to avoid hurting yourself while using your tool!


There are two types of impact wrenches, and their functionalities are more or less similar. The difference is where you use them. The electric wrench runs on electric power, while the air wrench also runs on air. You can try any of the two, and the experience will be excellent!

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