How Does An Impact Wrench Work?

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Impact Wrenches are a powerful tool that has made a lot of work much more accessible and easier. Yet, a lot of the time most of us are unsure about the mechanics of an impact wrench or how it works. Most widely known as impact wrench is also known as an air wrench, air gun, impact gun, or rattle gun.

However, most importantly all of these work with the same mechanics of rotating chasm, anvil, and the physics of kinetic energy. In this article, we are going to take a look at how an impact wrench work and what is the primary usage of such tools,

Uses of Impact Wrench

As it is a very powerful tool, it has numerous usage in a lot of industries. Primarily it is widely used in the automotive industry. Whenever we change the tires of the car, we need to remove the lug nuts and impact wrenches to do the trick.

Thus it is one of the most needed tools in any automotive repair shop or automotive assembly factory. Further uses of impact wrench also include in large construction projects and appliances factory as well as in the manufacturing, assembly, and maintenance of machinery and tools.

Types of Impact Wrenches:

How we separate the type of impact wrenches is where it gets its power from which is either electricity or air. That is because regardless of the type of Impact wrenches the working principle or how it works is essentially the same. However, each type of impact wrenches has their differences and their pro and cons, such as;

  • Corded Impact Wrenches:

There are wired impact wrenches that need to be connected to an electrical socket or power supply to function. Essentially it receives its power from the electricity. There is an electric motor that is fixed at the end of the wrench, powering the hammer and the anvil.

With electricity as the main power source, it has a faster torque and better speed control compared to its counterparts. It is also very portable as there is no need to carry an extra air compressor like the air impact wrench. However, compared to air tools, it is very expensive and is more prone to overheating inside the impact wrench

  • Cordless Impact Wrench:

A one step further from the corded one, it doesn’t rely on a power socket but rechargeable batteries making it one of the most portable impact wrench out there. There’s no need to carry any additional supplies and you can easily work in closed conditions. This cordless power tool is popular in car repair shops.

However, due to its heavy power usage, the batteries drain pretty quickly and need replacements. It’s also the most expensive option among all the impact wrenches.

  • Pneumatic Impact Wrench:

Pneumatic or air impact wrench, as better know, receives its power from compressed air pressure. Compared to its previous counterparts, the makings of a pneumatic impact wrench is quite simple as there are no electric parts. Thus it has a very sustainable source of power and has zero chance of overheating. It is also inexpensive.

However, the concern is that these impact wrenches are not very portable as they require a continuous supply of air pressure through a unit of compressed air. There’s also not much control over torque or speed as it is mostly receiving its power through compressed air.

How Does An Impact Wrench Work:

Regardless of the type of impact wrench, all of them have the same working principle which is applying a constant rotating force or impact. Mostly the energy in the impact wrenches is either powered by electricity or battery or air. Even though the air impact wrenches are the most popular for their sustainable energy sources, the inner working for all these impact wrenches is the same.

The Rotor: The rotor is the rotating element and the in-turn is the driving element for the hammer. Both of them are powered by either of the sources we mentioned before.

The airflow moves from the backplate till it reaches the rotating blades as that drives in a circular motion. The rotor inside is connected to an anvil which is an output shaft. When the energy from the rotor then reaches the anvil, it then drives the hammer mechanism.

The Hammer and Anvil: The hammer mechanism works in such a way that whenever there’s a force it removes itself from the anvil and the anvil is being resisted in a separate channel. The hammer slides away from the engaging pin and it then rotates in a velocity that is higher than it started and there is a build-up of energy.

Then, due to the very energy it rotates and gets connected to the anvil again. Thus, it forms multiple transfers of kinetic energy from the hammer shaft to the anvil and back and forth which results in an output of very high torque or rotating force on the final shaft.

The Output Shaft: This buildup results in a sudden consumption of the kinetic energy and that is when we see the impact wrench in action. After that usage of the energy, the output or the final shaft feels the resistance again putting the hammer and anvil into motion.

The whole cyclic process repeats, there are multiple transfers of energy again, leading to a  buildup, and then finally it reaches to the output shaft. This is how the impact wrench works and these cyclic blows are what make the impact wrench a highly valuable and efficient tool.


I think you should now have no confusion regarding how does an impact wrench works. Let me know if you have any more queries.

Also Read: Reviews of Best Inch Pound Torque Wrench

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