It’s difficult to imagine the immense torque (twisting force) that an air impact wrench can apply, but here’s an example. A nut that is “hand tight” requires a pressure of about 2 pounds per square foot—usually expressed as 2 ft-lbs. The best air impact wrench multiples that energy more than 500 times. Tough jobs like loosening lug nuts, where even using an extension bar on a standard wrench can prove insufficient, are a breeze for a good air impact wrench. You won’t find a pro auto shop without one, and they are also widely used in engineering and construction.
However, they are neither complicated nor difficult to use. So there’s no reason keen amateur mechanics shouldn’t have one at home, especially if they already own a versatile air compressor. They are also the perfect tool for driving lag bolts, or indeed for any job where hexagonal fasteners are used.
The following sections were put together to help you better understand the important features of these handy tools. Whatever fastener challenges you face, this information will help you find the best air impact wrench for the job.
- BEST OVERALL: AIRCAT 1150 Killer Torque 1/2-Inch Impact Wrench
- RUNNER-UP: AirCat Nitrocat 1250-K Air Impact Wrench
- BEST BANG FOR THE BUCK: ACDelco ANI405A Heavy Duty Pneumatic Impact Wrench
- UPGRADE PICK: Ingersoll Rand 22235QTiMAX Air Impact Wrench
- BEST FOR LUG NUTS: Ingersoll Rand 232TGSL Super-Duty Air Impact Wrench
- BEST COMPACT: Aircat 1056-XL-1/2″ Nitrocat Composite Compact Impact Wrench
- BEST LIGHTWEIGHT: Astro Pneumatic Tool 1822 ONYX 1/2″ Nano Impact Wrench
- ALSO CONSIDER: Sunex SXMC12, 1/2″ Mini Air Impact Wrench
- HONORABLE MENTION: WORKPAD 1/2-Inch Mini Air Impact Wrench
What to Consider When Choosing the Best Air Impact Wrench
It’s common to picture an air impact wrench in the hands of a mechanic attacking stubborn lug nuts. While that’s certainly a popular use for these tools, they offer a wide choice and plenty of versatility for just about all hexagonal fixings. The following looks at the technical aspects you will want to consider.
Torque is rotational force: the energy required to loosen or tighten screws, nuts and bolts, and so on. When you twist a screwdriver in a screw head, or put a wrench on a nut and push on the end, you are generating torque.
An air impact wrench is capable of generating way more torque than even the strongest person. The most powerful models considered here produce well over 1,000 ft-lbs. However, when looking for the best air impact wrench for specific needs, it’s more important to have the right amount of torque rather than the maximum available. While heavy-duty users might need the highest torque levels possible, any tool that generates 400-500 ft-lbs. will be sufficient for most. The terms “nut-busting” and “breakaway torque” are frequently used to indicate the maximum torque available for breaking free difficult fixings, though normal operating torque will be lower.
Depending on the intended use, it may be worth checking forward and reverse torque figures as they often differ.
Rotation Speed and Impacts
Rotational speed, given in revolutions per minute (rpm), is not the same as torque. Here it’s not about energy but about how fast the socket will turn. It’s an important consideration for those who work on multiple fixings because it impacts how quickly they can be fastened or loosened. Usually, manufacturers give this as “free speed” or “no load speed,” which assumes no effort is required to turn the fixing. In the real world, even a small amount of mechanical friction will reduce this speed. Nevertheless, it is useful for comparison purposes.
Air impact wrenches have hammer mechanisms within the tool that jolt the socket, increasing the effectiveness of the torque. Specifications are given as impacts per minute (IPM) or sometimes blows per minute (BPM). A higher number generally means a more aggressive action so if working with tough fixings is a regular task, it’s an area that warrants attention. That said, high IPM also means a tool will vibrate more, increasing user fatigue. Twin hammer actions help balance this out. While they still vibrate, it is less severe.
- Air demands: All air tools need a compressor to supply sufficient air pressure and volume. Pressure is given in pounds per square inch (psi) and volume in standard cubic feet per minute (SCFM, or sometimes just CFM). Air impact wrenches don’t have particularly high-pressure needs, but CFM demands can be higher than other tools. Checking these demands is vital. Many otherwise very good home air compressors may not produce the required supply.
- Weight and grip: Air impact wrenches come in a wide variety of sizes and materials. Weight can have a big impact on manageability and user fatigue, so while lighter tools tend to cost more (because materials are more expensive), it’s often money well spent. It’s also important to have a good grip on the handle, both for control and safety. Contoured and rubberized areas generally improve ergonomics.
- Noise levels: The hammer action of an air impact wrench is loud. While better manufacturers make an effort to reduce noise, most tools still exceed current safety levels. As a result, ear protection should always be worn.
- Sockets: While 1/4-inch drives do exist on light-duty air impact wrenches, most are 3/8-inch or 1/2-inch. This tells you the size of sockets you’ll need. It’s important that the sockets are of good quality. They should be marked as “impact ready” or something similar. Cheap socket sets are unlikely to stand up to the pounding they will receive and can actually shatter under the forces generated.
Tips for Using an Air Impact Wrench
In addition to the key technical features to consider when choosing the best air impact wrench, it’s important to be aware of the important practical and safety aspects of using these powerful tools.
A key component that might often be overlooked is the compressor required to supply air. Taken into account are the necessary air supply specifications, but optimum performance will only be achieved if the compressor itself is properly maintained. While air impact wrenches themselves need little maintenance, regular lubrication is vital. In both cases, it’s important to follow the manufacturer’s recommendations.
- Make sure the hose is properly connected to the compressor and that the air supply to the air impact wrench is set at the correct pressure (psi).
- Although many air impact wrenches can be used one-handed, make sure you have a good grip of the tool when loosening tight nuts and bolts. If the fixing breaks away suddenly, the torque reaction can make the tool jump in your hands and cause a nasty wrist sprain.
- Be careful when tightening nuts and bolts. If the torque is too high, the power of the air impact wrench can easily strip threads. If the tool is adjustable, you can always start at low pressure then increase it if the fixing is not tight enough.
- Always wear some kind of ear protection. Even air impact wrenches that are considered “quiet” may still exceed the 80-decibel limit above which hearing damage can occur.
Our Top Picks
Now that the key technical and practical elements of choosing the best air impact wrench are at the top of your mind, it’s time to apply that knowledge to models that are currently for sale. The following have been chosen for their performance, reliability, and value. While Aircat and Ingersoll Rand dominate the market, there are some interesting alternatives in several categories.
With so many good tools around, it is tough to pick the overall best air impact wrench. However, the 1/2-inch Aircat 1150 is likely the one that will appeal to most people, most of the time. It certainly offers impressive performance.
That “Killer Torque” name refers to the maximum nut-busting torque of 1,295 ft-lbs. Standard operating torque remains high at 900 ft-lbs., with three-way adjustment. A twin hammer action works at 1,400 BPM, and free speed is 9,000 rpm; however, at 4.5 pounds, this is not an unwieldy tool. It’s also among the quieter air impact wrenches at just 86 decibels.
Available as a stand-alone tool or with a number of extras, this model comes with three invaluable extensions to increase reach and versatility.
The 1/2-inch Nitrocat air impact wrench is another outstanding tool from the Aircat range. In pure performance terms, it’s even more impressive than the model that took our top spot, though it’s also more expensive and fewer people are likely to need the performance it delivers.
The breakaway torque figure is 1,300 ft-lbs., with a normal level of 950 ft-lbs. There is a three-way adjustment to maximize control. The twin hammer action is designed for heavy-duty applications, and the Kevlar-reinforced body offers tremendous durability in tough workshop environments.
For all its power, the Nitrocat 1250-K air impact wrench weighs just 4.5 pounds. At 86 decibels, it’s remarkably quiet for its type, too.
The 1/2-inch ACDelco air impact wrench is a great all-rounder that offers excellent value without too many sacrifices. The steel body should ensure good durability, and a maximum 500 ft-lbs. of torque is more than enough for changing wheels, lawn-mower blades, and other wrenching jobs around the home and yard.
Torque is not adjustable, but speed is, with four settings that go to a maximum free speed of 8,000 rpm. It’s a well-balanced tool with a comfortable handle, though at 5.7 pounds it’s not the lightest available. The sound level is 97.6 decibels, so it’s among the louder tools in its class. For occasional users those will be minor drawbacks, but its low cost puts it within the reach for those who might otherwise not have considered buying an air impact wrench.
With a nut-busting torque rating of 1,300 ft-lbs. and standard rating of 900 ft-lbs., the 1/2-inch Ingersoll Rand 2235QTiMax air impact range is among the most powerful tools in its class. A four-stage power regulator provides excellent control. The twin hammer action runs at 1,220 BPM.
The case is titanium, which maximizes strength without adding weight. The tool weighs just 4.6 pounds, and the main body is made from an impact and chemical-resistant composite for even greater durability. Ingersoll Rand’s “Quiet Technology” does a good job of minimizing sound, though at 91 decibels it’s not as quiet as some high-end competitors.
The Ingersoll Rand 2235QTiMax is a pro-grade tool designed for heavy-duty vehicle, industrial, and job site applications. The up-front investment should be repaid by years of trouble-free performance at the highest level.
Lug nut removal is one of the most common uses for air impact wrenches. The 1/2-inch Ingersoll Rand 232TGSL Super-Duty Thunder Gun air impact wrench is specifically designed for this purpose. While largely intended for professional use, it would make a great addition to the tool kit of the keen home auto enthusiasts.
Nascar fans might recognize the design, which is closely based on the race track tool. The Thunder Gun produces 625 ft-lbs. of maximum reverse torque and 550 ft-lbs. forwards, with a regulator for power adjustment. BPM is 1,250, and with a free speed of 10,000 rpm it is the fastest full-size air impact wrench currently available.
With a weight of 6 pounds, it is a bit of a handful, and its sound rating of 105 decibels means it’s very loud. Nevertheless, for those who remove lug nuts all day, the performance is hard to beat.
Standard air impact wrenches are very manageable tools, but sometimes it’s just impossible to get them into confined areas. The 1/2” Aircat 1056-XL was designed to overcome the problem. The head is just 4.25 inches front to back. With a weight of only 2.5 pounds and an ergonomic grip, it’s easy to use one-handed in tight spaces. A patented, trigger-mounted power management switch helps keep the tool compact.
Despite its small size, its performance is very competitive. Breakaway torque is 750 ft-lbs. and normal running is 550 ft-lbs. The free speed is 9,000 rpm. A composite housing helps protect it in harsh environments. The Aircat 1056-XL air impact wrench is also among the quietest tools on this list at just 85 decibels.
The 1/2-inch Astro Pneumatic Tool ONYX Nano is one of the most compact air impact wrenches on the market at a tiny 3.85 inches long. It is also among the lightest in its class at a mere 3 pounds.
Yet with a maximum 450 ft-lbs. of torque and working torque of 350 ft-lbs., it offers plenty of power. Three forward and three reverse settings also add versatility. It’s fast, too, with a free speed of 10,000 rpm. Despite that and the twin hammer action, the noise rating is a lowly 86 decibels.
The Astro air impact wrench will definitely appeal to engineers who often work in tight spaces, but given its low price, it would also make an excellent tool for the DIY user.
The Sunex 1/2” Mini Air Impact Wrench is among the lightest and most compact tools of its kind. It weighs only 3.2 pounds and measures just 4.29 inches front to back. That makes it ideal for getting into awkward spaces where full-size air wrenches often struggle.
Once in position, the power will not disappoint. The Sunex air impact wrench produces up to 500 ft-lbs. of breakaway torque with three levels of adjustment and a free speed of 9,500 rpm.
It can comfortably be used one-handed, though two are recommended for high torque applications. The 98-decibel noise level is comparable with many rivals, and the price is also competitive.
The Workpad 1/2-inch air impact wrench may not be from a top brand name, but it has all the features offered by many rivals and is all most home users will need.
Although it’s called a “mini” air impact wrench, the term applies to its compact size and is no reflection of performance. In fact, the power-to-weight ratio is excellent. A maximum of 500 ft-lbs. of torque is available, and there’s a three-position regulator for easy adjustment. Free speed is 10,000 rpm.
The tool has a durable, corrosion-resistant aluminum body that keeps weight down to 3.3 pounds. The only small drawback is the noise; At 112 decibels, it is louder than many.
FAQs About Air Impact Wrenches
The information above provides a comprehensive overview of these tools and will be invaluable in helping you find the best air impact wrench for your needs. That’s backed by a host of real-world examples of the top tools available. However, a number of questions crop up frequently, so see if yours is answered below.
Q. What does impacts per minute mean, and why is it important?
Impacts per minute (IPM), also referred to as blows per minute (BPM), is how fast the internal hammer action works to help loosen tough fixings. However, it’s just one of the factors to consider, as the guide above explains.
Q. Do air impact wrenches offer adjustability?
The best air impact wrenches offer a “power regulator” (also called an air pressure flow switch) on the tool to adjust air supply independent of the compressor. This effectively allows more precise control of torque. It’s sometimes referred to as speed control, though technically that’s not an accurate description.
Q. Are electric impact wrenches as good as cordless models?
It depends on the task. The best cordless impact wrenches are powerful and very convenient tools, particularly for light-duty tasks. However, some do struggle with higher torque demands, and runtimes can be modest. Corded electric impact wrenches often compete with their air-powered rivals. In many cases, an electric impact wrench can be a good choice for the homeowner, or for site work, but most automotive and engineering professionals still choose an air tool, perhaps in part because a compressor is usually available in those workplaces.
Q. Is drive size an important feature?
Drive size tells you the size of the socket the impact wrench uses. Most are either 3/8-inch or 1/2-inch. If you already own impact compatible sockets, this is important. Adapters from one to the other are available, but it’s not an ideal solution. If you are buying both air impact wrench and sockets, a 1/2-inch drive model is generally the more powerful.
Q. What size impact wrench do I need to remove lug nuts?
Removing lug nuts requires around 100 ft-lbs. of torque, so it’s a good idea to have an impact wrench that offers at least 150 ft-lbs. While some electric impact wrenches might struggle to achieve this figure, the majority of air impact wrenches can do so comfortably. You should never put lug nuts back on with an air impact wrench. It could easily overtighten them or strip threads. A manual torque wrench should be used to set them to the tightness recommended by the vehicle manufacturer.
Q. What is the optimum psi required for an air impact wrench?
Each tool has its own demands. Air wrenches need anywhere from 80 to 150 psi, so it’s a figure that needs to be checked, as does air consumption (see SCFM under “Additional Features” above).