how an impact wrench works

Just How an Impact Wrench Works

Ever since I was a kid I was fascinated by air impact wrenches, so whenever my dad took the car to have the tires changed, I always watched but never really knew how they worked so effortlessly, so I decided to look into it for myself.

How does an impact wrench work? Impact wrenches work by utilizing pneumatic or electric power sources to apply a series of sudden, intense, twisting bursts of toque to a lug nut.

When dealing with nuts and bolts, this type and level of applied torque is used to effectively and quickly work on the project, small or large, causing impact wrenches to be practically irreplaceable.

When is an impact wrench necessary?

An impact is necessary when replacing the tires or taking out the mags of your car, but can also be used for numerous other projects, perhaps such as tightening a screw to correct the level of a television to its rack with precision. Essentially, an impact wrench becomes necessary whenever you need more power for a bolt or nut and a hand tool or standard drill just cannot give you the raw torque you need to get it done.

This twisting motion of torque is measured in foot-pounds. The greater the torque, the better it twists. Torque is usually measured in the hundreds, from 100 to 500.

Why a flurry of strikes is effective

HowStuffWorks continues: “the continuous short, strong bursts of force trying to twist on the fastener are what eventually bring some movement (loosening or tightening)”. This is also called impact.

Physical contact with the bolt or nut being focused on either tightens or loosens the target screw.

Depending on the type or brand of impact wrench, the interval can vary. As the force builds up, it transfers energy to the screw, tightening or loosening it up immediately.

Impact is measured in the thousands, like rotation. Some companies opt to increase rotation per minute more than impact per minute.

Both are different in nature but work on the same page. More rotation and impact means the project part can be done easily without being too stressful for the user.

Furthermore, HowStuffWorks says that an impact wrench can run on air or electricity. The popular cordless impact wrench shall not be included here because this only talks about corded impact wrenches.

An air-type impact wrench is a pneumatic tool while the electric impact wrench runs on electricity.

An impact wrench powered by air is usually used on a race car that needs to have its tires replaced in less than one minute. Meanwhile, the electric impact wrench is used on virtually everything that needs speed and precision.

What else can you do with an impact wrench?

Regardless of its orientation, the impact wrench has primarily one job: to apply torque to a screw.

Nick Moore of Nick282K says that the impact wrench “stores energy in a heavy rotating mass and then releases it all at once in small impacts against the output shaft”. This is how the impact wrench buries the screw or nut into the surface.

This heavy rotating mass rotates and hits the target in a pattern. It should store energy by twisting the output shaft and releasing it in intervals, striking the head of the screw or nut.

It can also work in reverse, pulling it upwards. This is made possible by a locking mechanism that firmly puts the screw or bolt in place. Since this heavy rotating mass is fully-automatic, it removes stress from your wrist.

Is torque the same in electric, air, and cordless impact wrenches?

While torque has improved considerably in recent years in the cordless power tool area, pneumatic/air/gas impact wrenches are still the best bet for torque.

That isn’t to say that electric or even cordless impact wrenches don’t pack a punch, because that would be far from the truth. Today’s wired impact wrenches and portable impact wrenches are both quite handy and pack quite a punch, but also have a home in every mechanic’s garage.

Other questions about impact wrenches

How is torque measured in impact wrenches?

Torque in impact wrenches is measured in foot-pounds. Torque is the core aspect of every impact gun, a force it uses to push in or out a bolt or screw.

This makes the gun a tremendously important tool in working on project parts that may be too rusty and difficult for manual tools. If you are working on more than 100 project parts in a day, you should require something powerful like an impact wrench.

Are there cordless impact wrenches?

There are numerous cordless impact wrenches on the market. Black and Decker first introduced the cordless drill in 1961, which changed the future of power tools forever. It opened the door to the possibility of the battery-powered impact wrench that we know today.

What type of battery do cordless impact wrenches use?

The drill that B&D produced was powered by nickel cadmium, a battery that still sees some action in other power tools today, and actually does still have some advantages in certain situations. Lithium Ion is now the most common type of battery and has proven to be the most effective and energy-efficient of all, to-date.

Are cordless impact wrench batteries interchangeable?

Cordless impact wrenches have a universal battery hub. This enables the swapping out of batteries with each other as long as they are compatible and sport the same configuration. A cordless power tool will not work on a battery it does not support.

Do cordless impact wrenches work differently from corded or air impact wrenches?

Cordless impact wrenches still work under the same exact principles of torque and rotation that the air or pneumatic impact wrenches do. This is not different from corded ones, but can be more convenient to use on the road or in places where there are plenty of wires.