Choosing the best air impact wrench is incredibly easy!
All you have to do is answering three questions. What would be the speed of your ideal air impact wrench? How much torque will it provide? What would be the PSI and SCFM of the air compressor?
Don’t worry if you don’t have the answers to these questions yet. That’s why this article is here for. Read on to learn more about:
- In-depth buying guide for first-time buyers
- Top 6 products review
- Common questions when using an air impact wrench
What do you need to consider?
Let me get this straight, 1/2” drive air impact wrench may be all you need. I don’t have any 3/8” of air version. Instead, for tight spaces application, I used my cordless stubby impact wrench or a cordless ratchet. And a 1” version is probably too big for most people.
In any case, there are four major factors you need to look for to choose the best air impact wrench
- Average air consumption
Let me explain all these factors in detail.
Torque and Speed – What are your tasks?
Your tasks play a crucial role in deciding the torque and speed of your ideal air impact wrench.
- Heavy-duty tasks: Are you involved in heavy equipment maintenance? Do you work on major construction projects to earn a living? Then you’d need an air impact wrench with tremendous speed and torque output.
- Light-duty tasks: Are you an enthusiastic DIYer? Do you need an air impact wrench only to loosen the lug nuts of your car’s wheels? Then you may want to go for a smaller air impact wrench. One which produces less speed and torque and is compact.
Any force that causes an object to rotate around an axis is its torque. It is measured in foot-pound (ft-lb). In the case of air impact wrenches, you must pay attention to two types of torque.
- Forward torque: This torque forces the air impact wrench’s rotor to move in a forward/clockwise direction. It is responsible for tightening lugs, nuts, and bolts.
- Reverse torque: This torque forces the air impact wrench’s rotor to move in reverse/counter-clockwise direction. It is responsible for loosening lugs, nuts, and bolts.
Some air impact wrenches also mention “nuts-busting torque” on their packaging. This type of torque indicates the maximum power the tool can break a bolt that was tighten using another tool. And it is always greater than forward or reverse torque.
But you shouldn’t take the nut-busting torque seriously. Why?
Manufacturers mention these numbers to trick users into thinking that their air impact wrenches are more powerful than others. That, unfortunately, isn’t always the cause. In reality, you may never get the amount of torque that the manufacturer might have achieved in lab conditions. Here’s how:
Assume for a moment that you’ve torqued a bolt to 1,400+ torque. How hot will it be? Pretty hot, that’s for sure. Won’t that make it easier for you to remove it? Yup. But would the nut be as easy to remove if it was at room temperature? Nope.
Imagine you have two bolts in front of you. Both of them are torqued to 1,400+ torque. There is however one difference between them. The one on the left side is lubricated. The one on the right side isn’t. Which of them will be easy to remove? The lubricated one, of course.
That’s what manufacturers do. They lubricate high-torqued bolts before removing them with their impact wrenches. This allows their air impact wrenches to boast impossible-to-get torque numbers. Obviously, you can’t lubricate your 20 years old rusty bolt from the inside.
Pay attention to these two factors when checking an air impact wrench’s speed:
- Revolutions per minute (RPM)
How quickly will the air impact wrench drive nuts or bolts? Its RPMs determine the answer to this question. Wrenches with high RPM would get the job done quickly.
Most air impact wrenches on the market have an RPM range between 7,000 and 9,000 (without load). If you’re a home mechanic, that range is more than what you’ll ever need. As it will allow you to fasten/loosen virtually anything.
- Impacts per minute (IPM)
Their name makes it clear what IPM (aka BPM-blows per minute) is all about. It tells how many times the internal hammer strikes in 1 minute. The lower IPM, the harder it gets to control the tool and the more risk you put in your hand.
The majority of impact wrenches’ IMP range often falls between 1,000 and 1,600.
PSI and CFM – What air compressor do you need?
You may already know that air impact wrenches do not work in isolation. They require a specific minimum size air compressor as their power source.
Here’s what you need to consider when choosing an air compressor for an air impact wrench:
PSI stands for pound-force per square inch-indicate the pressure level. You need a compressor to deliver a pressure level of 90 PSI for an impact wrench to work properly. You must measure this number at the tool’s inlet, not the compressor’s outlet.
This is why you must get an air compressor whose output is greater than 90PSI. Only then will it can make up for the losses in its system.
Here are major factors that cause PSI drop
- Hose’s length: Ever used a garden hose to water your plants? What happened when you increased the length of the pipe? It led to a decrease in water pressure. The same thing will happen with the air compressor. An increase in hose length will result in a reduction of PSI.
- Hose’s diameter: Undersized air hose will cause PSI drop. When using an impact wrench, make sure your air hose diameter is at least 3/8”.
CFM and SCFM
- CFM (cubic feet per minute) refers to the air compressor’s output – or the airflow it can supply.
- SCFM (standard cubic feet per minute) refers to the compressor’s output at “standard temperature and pressure” which means at 68*F and 36% humidity at sea level.
Here’s what you need to look for:
CFM@90PSI of your air impact wrench
Air impact wrenches are intermittent tools – you take one nut off, release the trigger, turn it back on after a few seconds, and continue. You aren’t going to turn on the wrench and keep on using it for a full minute without taking a break.
That’s why you may see two types of CFM ratings on the wrench’s packaging:
- Average CFM rating: indicates the wrench’s CFM/flowrate based 25% use factor(15s on, 45s off). One that is common and followed by almost every mechanic. You must consider this rating to know if your compressor is strong enough to power the wrench.
- Full load CFM rating: indicates the wrench’s CFM/flowrate based on the assumption that you use the tool for 1 minute straight. You can divide it by 4 to get the average CFM rating.
SCFM@90PSI of your air compressor
For DIYers, you may pull out your impact wrench every once in a while. This is my recommendation for you:
- Air compressor’s SCFM@90PSI = wrench’s average CFM@90PSI.
On the other hand, if you’re a mechanic or you work on cars everyday, this is the ideal equation for you:
- Air compressor’s SCFM @90PSI = 1.5x wrench’s average CFM@90PSI.
Noise – How nice are your neighbors?
Impact wrenches’ noise is measured in dBA and ranges mostly between 85 and 95. The unit dBA is different from dB. While the dB scale only measures sound intensity, the dBA scale measures both the sound intensity and the human ear’s response to that intensity.
That allows dBA to give us a better idea of what sound level can damage our hearing. Experts caution that sustained exposure to noises in the 80 to 90dBA range may result in hearing loss. The keyword here is sustained and you should pay attention to it. Here’s why.
Sustained exposure means exposing your ears to the same noise level for 2 to 4 hours. Those of you whose exposure level to high noise meets or exceeds that threshold may want to invest in hearing protection devices.
Top 6 air impact wrenches review
These are the 6 air impact wrenches I enjoy using the most as a mechanic. I will analyze them in detail and guide you to choose the best one for your needs.
|Brand/Model||Max torque |
|Timmy’s pick||Ingersoll Rand 2235QTiMAX||900||4.7||$$$|
|Bang for the buck||AIRCAT 1150||900||4.5||$$|
|The noisy dwarf||Ingersoll Rand 35MAX||450||2.4||$$|
|Top choice under $100 ||Aircat 1056-XL||550||2.5||$|
|The quiet beast||Nitrocat 1250-K||950||4.5||$$$|
|The fluffy guy||DeWalt DWMT70773L||650||4.6||$$|
Timmy’s pick – Ingersoll Rand 2235QTiMAX
- Highly powerful
- Rugged design
- Durable titanium hammer
- Variable speed feature
- Finely tuned twin hammer impact mechanism
- Not quite balanced
- Relatively expensive
The Ingersoll Rand 2235QTiMAX offers many outstanding features. Foremost among them is its massive 900 ft-lbs of torque that lets you quickly tighten and loosen nuts and bolts. This model’s 8500 RPMs and 1220 IPMs limit means making short work of both light- and heavy-duty tasks.
Moreover, despite boosting such above-average features, this air impact wrench still has an average air consumption of 6 CFM@90PSI. One that can quickly be supplied by an appropriately sized air compressor that you will connect to this tool’s inlet.
It weighs slightly heavier than any average 1/2” air impact wrench and has dimensions to match that. But still, lightweight and compact enough for any mechanic. I myself used it a couple of times and had no problem with its weight (ok maybe a little) and size.
And yes, the plastic body is meant to make the tool lighter. But it also makes the balance a bit off. With a deep socket or torque stick mounted on the front, it feels front-heavy and difficult to hold for a long time.
One more thing, 91.9 dBA will mess with eardrums and give your neighbors a hard time. You can easily deal with its noise by wearing ear protection devices or by adding a noise filter. And you’d have to do that if you want to enjoy this model’s one-year warranty, which, even for an impact wrench that costs more than $250, is impressive.
Final Verdict: The Ingersoll Rand 2235QTiMAX provides more than enough power for your typical cars, light trucks, and similar automotive jobs. Therefore, it’s a must-have if you need an impact gun in a small package with lots of power.
Bang for the buck – AIRCAT 1150
- Patented quiet technology
- 15% larger rotor than similar models
- Massive torque and speed output
- High average air consumption
- Strong vibration
Multiple features of the AIRCAT impact wrench make it a must-have. The first is its 900 ft-lbs torque that delivers the sheer power necessary to deal with the most stubborn bolts. The second is its combo of 9000RPM and 1,400 IPM, allowing you to quickly wrap up your projects.
However, “with great power comes great vibration”, said uncle Timmy. Yes, the tool’s vibration may cause the socket to slip off and scratch your wheels if you aren’t careful. My little trick is to put a small piece of paper between the socket and anvil. It totally works!
Average air consumption of 8 CFM comes across as a double-edged sword. On the one end, it provides the impact wrench with sheer output power. On the other, you’d have to invest more in an air compressor, as budget-priced compressors may not be able to supply that much air.
More impressive is this model’s operating noise level. Rated at 86 dBA, it means you can work for hours without ear protection.
And the best thing about this product? It’s just a bit more than 150 bucks and is backed by a two-year warranty!
Final Verdict: The AIRCAT 1150 air impact wrench is a must-have for technicians or even DIYers. A balance between power and price, along with other features and 2 years warranty. It worths every single cent!
The noisy dwarf – Ingersoll Rand 35MAX
- Easily gets in tight spaces
- Featherlight-save your wrist
- 2 years warranty
- Low torque
The Ingersoll Rand 35MAX is much more affordable compared to the two above. This is why its 450 ft-lbs of torque cannot compete with what they offer. Ok, let’s face it, 450 ft-lbs is a lie. I used it with a monster air compressor in my garage, and 170 is the highest number I got. But actually, it’s still more than enough for most light-duty automotive tasks and similar projects around the home.
But why is it so special? Well, because it is an ultra-compact model. The tool only weighs 2.4lbs-save your wrist! The stubby 4.6” length and compact design give you access to various odd positions in the engine bay.
One of the best features of this model is its low air consumption. It requires only 4CFM at its inlet and can therefore be operated by your average air compressor. You won’t have to invest in a high-end model to power this tool.
Despite its relatively meager power output, it churns out 96dBA noise when running at full speed, which is at least 4dBA more than the 2nd noisiest wrench in this review. Along with its lightweight and ultra-compact design, that why I call it “the noisy dwarf.”
Though it more than makes up for this shortcoming with its below-average price and a two-year warranty. Not to mention its 3-mode power regulator give you much better control.
Final Verdict: The Ingersoll Rand 35MAX won’t hit you hard in the pocket, comes with a 2-year warranty, and is incredibly compact. All these features make it a worth-mentioning option for both mechanics and DIYers.
Top choice under $100 – Aircat 1056-XL
- Competetive price
- Provides ultimate control
- Compact and lightweight
- “Silencing Technology” keeps noise in check
- Relatively low torque
- Uncomfy grip for big-hand people
- High air consumption
Several features make the Aircat the top choice under $100. It provides 550ft-lb maximum torque, twice as much as you get from other options in this price range. Again, I don’t believe this number. But its actual torque is still powerful enough to remove any crank bolts, struts, subframe bolts, and more.
However, you’d need a slightly expensive compressor to provide enough air (8CFM@90PSI) for the tool. But you’d be rewarded for spending more with this unit’s 85dBA noise, which makes it the quietest of any wrench we have discussed thus far.
Maneuvering this model in tight spaces is incredibly easy too. Its lightweight (2.5lbs) and compact design make it a much more quiet version of “the dwarf” I mentioned above. Yes, another “dwarf”, but this one is more affordable and eats more air.
Final Verdict: The Aircat 1056-XL 1/2” impact wrench deserves your attention if you’re looking for a budget option to remove tire calipers, struts, or anything that need a bit more power than what your average-budget air impact wrench can offer.
The quiet beast – Nitrocat 1250-K
- Easy to use
- Operates quietly
- 2 year warranty
- Massive air consumption
- Placement of forward and reverse switch could be better
- Low IPM-harder to control
The Nitrocat 1250-K air impact wrench features a maximum speed of 8,500RPM. Together with its twin-clutch mechanism, its 950 max torque makes it better suited for heavy-duty projects, i.e., working on medium to heavy-duty pickup trucks. However, this tool’s IPM is just 1000, which will give your wrist a hard time.
Your standard air compressor won’t be able to meet this model’s air consumption requirements. Only the most powerful compressors would be needed to supply it with 8CFM@90PSI. But this model will make the most of any power you supply to you. Here’s how.
Nitrocat has equipped this wrench with its patented tuned exhaust muffler technology. Apart from helping it retain power by allowing air to exit without creating back pressure, this technology also enables it to operate at a relatively quiet 86dBA. This is why I’ve termed it “the quiet beast”.
It’s may not as light as some of the other models in this review. Still, Nitrocat, by providing it with an ergonomically designed handle, ensures that you encounter minimal hand and wrist fatigue when using it. Ok, I get the idea, but why don’t you guys just increase the IPM a little more?
Good news, you might not ever need the 2 years warranty. I myself dropped it a few times, once into the oil. It still busts the nuts right off. I’m more afraid that this thing will outlive me!
Final Verdict: The Nitrocat 1250-K air impact wrench is one of the best options to have if you engage in heavy-duty tasks or regularly work on medium to heavy-duty pickup trucks.
The fluffy guy – DeWalt DWMT70773L
- Shock-resistant bumpers
- Not so noisy
- Easy to operate and maneuver
- 3 speed modes- more control
- 3 years warranty
- Less torque and speed compared to same-weight brothers
Nah, it’s not that fluffy! But compared to other models with the same weight and size, it delivers much less torque and speed.
However, 650ft-lb is still more than enough to break free fasteners, and the 7,500RPM speed empowers this unit for dealing with high-power fastening applications.
It may have above-average power requirements but not one that cannot be met by your standard air compressor. This model also boasts one-handed operation with its forward/reverse switch that allows for easy (and quick) directional changes without fatiguing your wrist.
Equally impressive is its 87dBA noise, which is less than average. You can therefore keep on using it for hours without investing in an ear protection device. Moreover, the ergonomics is not bad-not too heavy (4.6lbs) or bulky.
Dewalt also offers a 3-year warranty for this fluffy guy. Again you’re probably not gonna need that. A shock-resistant bumper will protect this tool well enough. I don’t use it much, so most of the time, it lied in my dirty toolbox. But whenever I needed it, I gave this guy a drop of oil and we’re totally good to go.
Final Verdict: The DeWalt impact wrench is worthy of your attention if you’re looking for something to tackle your struts, lug nuts, and changing tires. A decent choice for both mechanics and DIYers with a balance of torque, speed, and cost.
1. Why should you always lubricate an air tool before operation?
A: Lubricating an air tool before operating it will provide you three specific benefits. Regular oiling prevents moving parts – both inside the air tool and outside it – from grinding against each other. This saves the tool from corroding itself into uselessness.
Regular oiling also prevents heat build-up between two moving parts. Surfaces that are regularly oiled are at a lower risk of wearing down as well. That’s because lubricants form a protective, low-friction layer on the surface of the part where they are applied. This saves the surface from corrosion.
2. Are electric impact wrenches as good as air?
A: Electric impact wrenches are less potent than their air-powered counterparts. They are more expensive and difficult to use, too, due to many settings. And since they are bigger and bulkier, carrying them around isn’t easy as well.
On the flip side, electric impact wrenches are easy to set up and use. Unlike air impact wrenches, these devices work straight out the box and aren’t bulky as well. All these factors justify the selection of air impact wrenches if you want your model to be more powerful and easy to carry.
3. Does CFM change with PSI?
A: According to the following equation, there is an inverse relationship between CFM and PSI. That means that if CFM increases, PSI decreases, and vice versa. Engineers take advantage of this fact by reducing the compressor’s air pressure whenever they feel the need to increase its CFM.
Here’s the equation: Power = Pressure (PSI) x Flow (CFM)/1714
4. Will a 3-gallon air compressor run an impact wrench?
A: You can use a 3gallon air compressor to run an impact wrench but you shouldn’t. Such compressors can power the wrench as long as the PSI is not too low, but the wrench will then operate for a short amount of time, before shutting down and waiting for the compressor to fill up.
As you might guess, this arrangement will take years to get the job done. Which is why we recommend against using a 3-gallon air compressor to run an impact wrench.
5. Will a 6 gallon air compressor run an impact wrench?
A: Scroll down to our product reviews section to find the answer to this question. There you’ll notice that the average air consumption of almost all models is greater than 6CFM@90PSI. Most 6-gallon air compressors, however, range between 2.6 to 4SCFM @90PSI.
That’s why we recommend that you don’t use a 6 gallon air compressor to run an impact wrench. Otherwise, you’d be spending the entire day – and expending lot of effort – just to take that wheel nut off!
This article contains everything you need to know to purchase the best air impact wrench for your needs. That includes a detailed buying guide – listing everything you may want to look for in an impact wrench, as well as reviews of the top six models currently available on the market.
We have also answered some common questions about air impact wrenches. You can now tell anyone with confidence why they shouldn’t bother trying to run an impact wrench with a 3-gallon or 6-gallon air compressor. Or why in some cases, air impact wrenches are better than their electric counterparts.
Now, let bust some nuts!