Last Updated on July 13, 2022 by Georgie Smith
An impact wrench refers to a tool used to aid the tightening and loosening of nuts and bolts. The use of the tool reduces the effort required in loosening or tightening bolts and thus increases the speed of working. Impact wrenches come in types based on what powers them. They include:
- Air Impact Wrench
- Corded-electric Impact Wrench
- Cordless-Electric Impact Wrench
- Hydraulic Impact Wrench
- Manual Impact Wrench
However, this review limits itself to Air Impact Wrenches. An air impact wrench happens to be a type of wrench, powered by compressed air. The tool connects to a compressor via a hose, then compressed air from the compressor supplies the pressure needed to power the wrench.
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Air Impact Wrenches are very handy and used vastly in the completion of various automotive works and home projects. The hammering action of this power tool makes worker’s life much easier and jobs less stressful. You don’t have to worry about stubborn bolts or nuts with an air impact wrench nearby.
Different brands exist on the market; however, we handpicked Aircat 1150, Snap-On Mg725 and Nitrocat 1200K then compared and contrasted them. Do read the result below:
|Aircat 1150||Snap-On Mg725||Nitrocat 1200K|
– It comes with 15 percent larger rotor than others
– It stands as the hardest hitting air impact wrench
– It produces low noise which remains a good advantage when you have to work for long hours.
– Special patented tuned exhaust system for low noise emission
– Lightweight and versatile unit
– Adjustable torqued unit ranging from 200-900 ft. lbs.
– It has the capability of handling all repairs with ease
– It comes in a very durable lightweight construction and minimal vibration
– It has faster motor start-up and greater performance torque.
– It comes with anvil stop feature for safe operation.
– Comfortable cushion grip button that delivers improved control
– It works with fewer parts and less downtime
– Come with slim style nose for working in tight spaces.
– It can withstand even the most brutal repair shop conditions due to the Kevlar composite construction.
– Its exhaust passes through handle to keep debris away from the operator‘s face while blowing it away.
– It generates low noise at 86dB.
– It comes with easy fingertip controls which make for easy forward-reverse operation without disrupting the power.
– It comes with a twin clutch
– It executes medium to heavy-duty truck repairs perfectly.
– According to users, it vibrates violently when removing lug nuts and if not held properly can jump off and dent nearby surface.
– The socket and the gun might wear our faster due to the excessive vibration.
– Variable trigger comes stiff
– Max torque can be complicated to set-up
– It happens to be the least powerful impact wrench in the shop.
– If the muffler does not come with it, it will become as loud as others.
– Though pretty strong for most application yet not very strong in others
– It has a longer impact than some others thus some suspension components are impossible to use with this unit.
– It has a seal on the nose cone that leaks after moderate use.
– Two-year parts and labor warranty
– Two-year warranty
– Two-year warranty
Top 3 of The Best Air Impact Wrench for Home Use:
AirCat 1150 Reviews:
The AirCat 1150 Killer Torque ½-inch Impact Wrench comes loaded with sheer power. With 1,400 Blow Per minute, this bad boy stands as the strongest hard-hitting Twin Hammer ½-Inch Impact Wrench on the market. It also comes with a performance of 1,295 feet-pounds (ft-lb) of loosening torque plus maximum torque of 900 ft-lbs.
The Aircat 1150, although powerful yet weighs lower than expected at just 4.63 pounds you can use this compact tool with ease. Couple with the weight, it also comes with an ergonomic handle for comfortable use.
Snap-On Mg725 Reviews:
The Snap-On Mg725 1/2-inch Drive Super Duty Impact Wrench represents an attitude, power, durability, balance, and good looks. The unit can deliver an outstanding 1,190 ft. lbs. of Bolt Break Away Torque – such power! It also comes with 810 ft. lbs. of Working Torque. It comes with machined magnesium housing for an extremely durable, lightweight, and balanced unit.
It gives off minimal vibration and comes with superior control which makes for less user fatigue and longer tool life. To make the unit cooler, it comes with an 8-vane rotor for faster motor start-up and excellent performance.
NitroCat 1200K Reviews:
The NitroCat 1200K ½-inch Kevlar Composite Air Impact Wrench with twin-clutch mechanism boasts as the most powerful ½-inch impact in its class. It comes with a durable Kevlar composite housing. You will not complain of fatigue when you operate it because of its ergonomically designed handle.
It comes with 1,295 ft. Lbs. torque to outperform anything in its class. Do you know that many NHRA Top Fuel race teams use this no-nonsense bad boy? Join the league of important people by adding NitroCat 1200K (valuable addition) to your air tool workforce. It comes with low noise of 86 dB.
Which One Should We Buy?
After reading the product review and comparison, you might want to know which to buy with all the brands on the market. Many features abound to consider helping you decide which impact wrench to buy. Also, your job type will go a long way to affect your choice. For instance, occasional users will require a different kind of impact wrench compared to frequent users. 
Now let us consider the following factors to help you decide:
Torque refers to the force required to turn or fasten a screw. There should be enough torque to remove a fastener, hence the importance of this factor. The higher the torque, the stronger the impact wrench. The minimum torque to consider should be 150 ft. lbs. (1,800 in. lbs.).
Impact Per Minute
The number of times within a minute the hammer hits the anvil refers to the impact per minute or IPM. A higher IPM wrench drives screws faster and has the capability of loosening tight bolts better.
The following are the drive sizes available:
- ½-inch drive – The most common out of the three and will execute most applications
- 3/8-inch drive – The second most common size but comes in a smaller total package. It, however, has lower torque compared to the ½-inch drive wrench.
No Load Speed
Just like the term, it means the speed of a wrench when it bears no load not being used on any bolt. Naturally, a higher speed will fasten screws faster, but a higher speed will result in a lower torque.
Small compact wrenches seem better since it can be used efficiently in tight spaces. Small wrenches usually have lower torque. Consider an impact wrench that tends to blend size and torque.
To avoid over-torqueing a bolt or snapping a bolt head, torque adjustment becomes imperative. Torque adjustment gives you control over the torque output of the wrench.
Wrenches differ in weight, while some are heavy others are light. If your task happens to be a short one, the weight of the wrench might not matter. However, for the more extended projects, the need for a light wrench cannot be overemphasized because prolonged use leads to fatigue. Heavy wrenches are not easy to control especially when the operator is tired.
Balance and Ergonomics
You can easily have a good grip on some wrenches compared to others. The design varies from brand to brand. When buying get one that fits your hand perfectly and that gives the needed comfort.
Get an impact wrench with a decent warranty for the much-needed peace of mind while you use your wrench. Warranty varies from manufacturer to manufacturer.
Summing up, you should be able to marry the features highlighted above together with your need to get the best impact wrench for you. However, do note that you should not let the features take priority against the intended use. In plain terms, do not sacrifice the purpose of the tool on the altar of the features of the same.
Are Impact Wrenches Adjustable?
A few years after the Impact Wrench was invented, you cannot easily get an adjustable Impact Wrench. However, due to product modernization air impact wrenches now come with adjustable torques.
With the impact wrench, loosening stubborn bolts becomes effortless. However, using an air impact wrench to tighten a fastener to the right position again using the correct torque can be a bit challenging.
The right amount of force necessary for the fastener will depend on the air pressure amount that is available. Due to the preceding, manufacturers today developed air impact wrenches with adjustable torque. 
Few of the Benefits
- An air impact wrench with adjustable torque will exert just the right amount of force required to get jobs done with ease.
- When it comes to projects that require specific tightness, e.g., the tightness of bolts and screws, an adjustable impact wrench will foot the bill.
- With an adjustable torqued impact wrench, an operation can easily measure the torque required to match specifications in various applications.
- The adjustment of torque will aid the right loading and tension of all the parts. Using an air impact adjustable wrench will help with different tasks.
How Does It Work?
Using the adjustable air impact wrench takes two steps. Those two steps require two types of adjustments, viz:
Step 1. Regulate the line pressure
- Turn the compressor on and leave it to run till it gets to the shut-off pressure.
- Attach your impact wrench to the compressor using the air hose
- Lessen the available air working pressure to the line by adjusting the regulator of the compressor
Step 2. Regulate the tool pressure
- With the air tool adequately attached to the tool air regulator, adjust the tool air regulator
- Keep adjusting the air until it reaches the specified amount of torque you desire.
What Are Impact Wrenches Used For?
In an automotive shop, when all else fails, to what do you turn? Well, when all other wrenches refuse to work, an impact wrench stands as a tool to last option. If you have ever been in the following situations, you would appreciate what this section addresses:
When the lug nuts, you want to undo wound too tightly in place and become hard
to come off.
When after trying with your manual wrench but the screw head gets stripped that
your wrench could not have a good grip.
When you are trying to reach a bolt in a tight space that makes it difficult to turn your wrench
Whichever scenario you find yourself in any or all of the above examples, an impact wrench lets you add extra force. Along with extra force, you get a good grip on those hard-to-turn bolts or nuts. When you use the impact wrench correctly no lug nut no matter how tightly fitted can conquer you. Air impact wrenches by design can deliver high torque as fast as possible.
Let us consider in summary the uses of the impact wrench:
- You can use the impact wrench to loosen machine-tightened nuts and bolts. The reason is since they are tighter than regular hand-tightened ones, extra force is necessary.
- You can use the impact wrench to remove and re-install lug nuts, e.g., changing tires on a car.
- You can use the impact wrench to tightly secure heavy items such as shelves for holding heavy tools, brackets for bikes, or other heavy things.
- Impact wrenches can remove stuck bolts that have stayed for years.
- It can also help to remove nuts or bolts in tight spaces.
- Impact wrenches save the mechanic the exhaustion of using a breaker bar all the time. The use of the impact wrench reduces job-related injury associated with manual wrenches.
- When speed becomes important, the impact wrench fits the bill. For this purpose, the impact wrench features in F1 races because F1 mechanics use it during tire change – a time-saving advantage.
- Automotive works such as working on cars, small engines, etc. can be done with ease by an impact wrench. Besides working with ease, the tool secures the nuts and bolts firmly on the machine so that it does not come off while the engine or car works.
How Do Impact Wrenches Work?
An electric or air-powered impact wrench comes with an electric or air motor. The motor applies a sudden, powerful twisting motion to lug nuts or on stubborn bolts. The motion occurs in short bursts (every five seconds or so). The continuous short, strong bursts of force twisting on the fastener eventually lead to the desired movement (loosening or tightening).
An Impact Wrench comes in handy during assembling and disassembling jobs. Furthermore, to improve the torque of the air impact wrench, the pressure provides extra force by pushing the targetted fastener forward. This pushing action helps the tool to deliver its job better than when you go manual.
Impact Wrenches make mechanical work easy. An air-powered impact wrench has been considered to be the most professional-grade impact wrench since it provides the most torque. Generally, air impact wrenches are lighter than others and easier to use.
The electric impact wrench, on the other hand, can provide enough punch needed for your DIY (do-it-yourself) operations. Hence, an electric impact wrench should be kept in your car for tire changes since you cannot easily access an air compressor on the road.
Impact Wrench Won’t Shut Off
We hear users complain about their impact wrenches encountering trigger-related problems. Trigger-related issues become evident when the impact wrench refuses to shut off. Now if you encounter such issues, do not fear, we have the solution here.
There are two ways of fixing the problem:
Solution 1: Oiling the air intake
Apply thin lubricating oil to the air intake to see if the trigger can respond. If the problem persists, then you have to consider the second solution.
Solution 2: Take the impact wrench apart.
Once the oiling did not work, it means the trigger is broken and needs replacement. The few steps are highlighted below though require due care on your part. Now if in doubt of your ability, contact an expert.
Remove the trigger by first removing the pin which is the impact wrench’s pivot. Use a flat table without holes or cracks to prevent the pin from getting lost in them.
Position the striking surface of the punch on the head of the pin found at the side of the impact wrench’s handle. Strike the smaller side if one side is larger than the other.
Strike the head of the punch sharply with the hammer to loosen the pin. You might need to apply several blows for the pin to come out of the handle.
Pull the broken trigger pieces out of the impact wrench’s handle. Place the replacement plastic trigger in the place of the old broken one. Now tap the pin carefully into the trigger hole to prevent damaging the new trigger.
Set the pin correctly once it has fit perfectly into the opposite hole in the impact wrench. Test your new wrench and see it go. It should work perfectly if you install it well.
What Size of Impact Wrench is Needed for Automotive Work?
Automotive work varies in size and complexity; hence each job requires different torque to get the job done with ease. The best impact wrench is not the one with the highest torque or the most precise. On the contrary, the best impact wrench must be the one that fits your job requirement.
In practice, when choosing the best wrench, you must consider the work and the force needed to get it done. Furthermore, when selecting the best size impact wrench for your automotive job, you check the torque and precision. The following examples are torque required for your automotive work:
Extremely Light Duty Tasks:
Standard maintenance of engines which includes fastening spark plugs change, oil drain plugs, valve cover bolts, and so on falls under extremely light jobs. The required torque for extremely light jobs ranges from 15-75 ft. lbs.
When you carry out common repairs which range from head bolts, lug nuts, and caliper bolts fastening, you operate under the light task category. Most automotive repairs fall into this category. Since most automotive maintenance fall under this category, an impact wrench for this category must be in your toolbox. The required torque for light jobs ranges from 30-150 ft. lbs.
Moderate Duty Tasks:
When the job at hand involves fastening axle bolts, hub bolts, and bolts on installed trailer hitches you need a moderate task wrench. These common automotive fastening applications are few but critical. To execute moderate tasks, you need a wrench with a range between 50 and 250 ft. lbs.
Operations like Driveline components and bearings, jobs involved in the transfer cases, and differentials all are heavy-duty jobs. When heavy-duty tasks call, an impact wrench of torque of between 120 and 600 ft. lbs. will suffice.
Extremely Heavy-Duty Tasks:
Applications under this category include camshaft sprockets and harmonic balancers. Many off-road vehicles or performance racing vehicles require torque in this range. The torque needed for this operation range from between 200 and 1,000 ft. lbs. or even higher torque.
In summarizing, as earlier mentioned, the automotive job you do will determine your wrench need. For instance, if your job involves oil changes and tune-ups, light or very light torque wrenches will foot the bill. Contrarily, if you specialize in heavier-duty repairs, e.g., rebuilding engines or transmissions or handling structural repairs like an axle or hub job then get a heavier wrench.
Q: How much torque do I need to remove and install a lug nut?
A: An unstuck lug nut would require 100 ft. lbs. of torque to move. For this case, an air impact wrench would be handy because it can deliver much higher amounts of torque to deal with demanding jobs and for speed. In conclusion, do not over-torque a bold beyond the manufacturers’ recommended specification.
Q: I run a home garage, please can you recommend the type of impact wrench that I should buy?
A: As a home garage owner, an impact wrench that can execute light applications will be the best type that you should buy.
Q: Can a manual impact wrench loosen rusted and frozen bolts and nuts?
A: Well a manual impact wrench may or may not be able to loosen rusted and frozen bolts and nuts. The manual impact wrench can loosen such bolts if it’s small or medium and not so rusted or frozen.
Q: What kind of air compressor should I buy?
A: For a single air impact wrench, an air compressor of a minimum of 6.5-7 CFM to 90 PSI for the average ½-inch impact wrench that requires 5 CFM. However, if you like to run more than one impact wrench at the same time, then your compressor must be able to deliver more than the sum of its CFMs. You can calculate this by adding the CFM of each of them.
Q: I hear air compressor dealers talk about PSI and CFM; What do those terms mean?
A: PSI means pounds per square inch. PSI measures the amount of air compressed into a given space. Note that PSI measures stored air and not continuous airflow. CFM, on the other hand, means cubic feet per minute. CFM measures the amount of air flowing at a given moment.
CFM determines how much power an air impact wrench will have at its disposal. PSI determines how long your air compressor can deliver that CFM before it needs to recharge.
As earlier said, choosing the perfect air impact wrench must be based on the intended use of the same. and other features. We believe that as you have read this post conscientiously, you have become a wrench guru. You are likely to buy a wrench based on sentiment or other baseless reasons. You also know now that all impact wrenches are like our fingerprints – uniquely different.
Judging by this our 2019 reviews, comparison, and analysis of AirCat 1150, Snap-On Mg725, and NitroCat 1200K, you should be all set to get the best of the best. As you know our submissions are without sentiment or biases. If you follow our tips, you will not be at a loss in the market jungle of air impact wrenches.
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