Impact wrenches are one of those tools that you find in many toolboxes, but their exact purpose is not as well known. That’s because an impact wrench is a tool that is used occasionally for most people. Even on a construction or demolition job, an impact wrench may still only be occasionally used, but you’ll appreciate it being there for you when needed.
If you have watched any auto racing events or watched an auto mechanic change tires, then you have most likely seen an impact wrench at work. The distinctive whirring sound that accompanies the use of an impact wrench is quite loud, so you should wear ear protection if you are using this device. A typical impact wrench can loosen lug nuts that have been tightened to 100’ of torque.
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Uses of Impact Wrenches
They are primarily used to loosen lug nuts so they can be removed. Lug nuts are most associated with tires on vehicles, but they can be used to connect different types of parts. Impact wrenches are used in construction and demolition work. They are quite handy when loosening old, rusted lug nuts that manual lug wrenches cannot budge.
In addition to loosening lug nuts, the impact wrench can be reversed to tighten them once again. Because they use a hammering impact, the nuts will be tightened considerably more compared to using a manual lug wrench which may or may not be desirable depending on the situation.
The impact wrench usually has different size heads to fit the variety of lug nuts that are available. The most common is the type found on vehicles, but there are other sizes as well.
How It Works
A standard manual lug wrench is what you have in your vehicle as part of your tire-changing kit. You find the right size, put it to the lug nut, and turn. And while an impact wrench has the same connection, it is a different type of device.
The mechanized impact wrench is a device that looks similar to a power drill but operates on a somewhat different principle. The torque that is generated from an impact wrench comes from the successive hammering blows that it delivers to the lug nuts in quick succession. You can see this in action as you first apply the impact wrench and see it move slowly, then it moves quickly once the nut has been loosened.
The same is true when the impact wrench is reversed, and the hammering action tightens the lug nut in place. However, for the most part the wrench is used to loosen and not tighten lug nuts as standard manual wrenches can do that job just as well.
How to Operate an Impact Wrench
Once you have purchased an impact wrench, you will need the proper gear for protection as you operate the device.
- Gloves
- Safety Goggles
- Ear Protection
The gloves should have rubber to help absorb the vibrations of the impact wrench. Plus, the coating should help you get a better grip on the device. The safety goggles are there just in case rust or other particles that have been loosened by the impact wrench do not lodge themselves in your eyes as they fly off the lug nut.
The ear protection is to protect your hearing. Impact wrenches can be quite loud when up close. So be sure that you are fully protected before turning on the impact wrench.
Once you are prepared, start up the wrench with a couple of short bursts to see that it is functioning correctly. Now, set the opening over the lug nut to ensure a tight fit. Once you are ready, turn on the impact wrench and let it do the work.
There will be a temptation to turn your wrist to help loosen the lug nut, but you do not want to strip the nut by accident. Instead, press the impact wrench into the lug nut and let the device turn it until it is fully loosened and removed. Set aside the lug nuts so you can find them easily when you are ready to replace them.
If you are changing a tire, the impact wrench will be quite handy. The only thing to keep in mind is when you replace the tire and apply the lug nuts. A nut that has been replaced by an impact wrench will be quite tight. So, unless you have an impact wrench around if the tire should go flat, expect to put in some muscle work to loosen the nuts.
You may instead want to tighten the lug nuts with your lug wrench instead. This way, in case you get a flat tire and you do not have a impact wrench around, you can still loosen the lug nuts manually.
Impact Drivers
An impact wrench should not be confused with an impact driver, but the function may seem similar at first. This type of wrench is used to loosen lug nuts, mostly from the wheels of vehicles. However, it can be used in any situation where a considerable amount of torque is needed. One difference between an impact wrench and an impact driver is that the former has ½” sockets to fit a lug for wheels. While the latter has a ¼” hex opening.
Apart from that, they do look similar and operate in roughly the same way. If you decide that an impact wrench is for you. Be sure to look over the labels, so that you know that you are getting an impact wrench and not an impact driver.
Impact wrenches are most often used in commercial work, particularly auto shops and pit crews that must loosen lug nuts on a regular basis. For vehicle owners, an impact wrench may be seldom used depending on the circumstances, but it is a handy device to have. This is particularly true when you need that extra power to loosen a stubborn lug nut or remove nuts that have rusted in place over time.
Founder of HandymanGuides.com and self-proclaimed “Mr. Fix-It”, Mike has countless years of experience building and tinkering with everything under the sun. He works as a local repair guy near Santa Monica, CA and when he’s not spackling drywall, he enjoys spending time with his wife and 2 daughters.
