A pneumatic impact wrench is used to quickly loosen and tighten threaded connections of various sizes and diameters. There are many models on the market today, so choosing an air impact wrench can be quite difficult. So that choosing the right option does not become confusing and difficult for you, we suggest you figure out how to choose an air impact wrench and what aspects to pay attention to.
How to choose a wrench?
In this material we will try to tell you in as much detail as possible about what points you need to pay attention to when choosing a pneumatic impact wrench. After all, when it is necessary to perform a specific plumbing operation, you must be sure that the pneumatic tool will not fail.
Before answering the question of which pneumatic impact wrench to choose, you need to familiarize yourself with their main types. This material is discussed in a separate article here.
How to choose a pneumatic impact wrench? Find out!
Each model has many different benefits and amenities to consider before making a purchase.
Below is a list of features you should rely on when choosing a wrench.
- The presence of a striking mechanism;
- Maximum torque;
- Connecting square size;
- Air flow and operating pressure;
- Rotation speed of the working shaft (spindle);
- Features of the case (material, type, size, additional handle);
- Working shaft length;
- Power adjustment;
- Weight;
- Ergonomics and reverse switch;
- Equipment;
- Warranty, service center and availability of spare parts;
- Country of Origin;
- Price.
Having listed all the parameters that you need to pay attention to, we will try to talk about each in more detail in order to decide which pneumatic impact wrench to choose in a particular case to solve the problem.
Presence of impact mechanism
As a rule, all pistol and straight impact wrenches have an impact mechanism. Due to the shock-rotating action of the working shaft, even the most rusty and “stuck” threaded connections are unscrewed.
In most cases, air ratchets are considered non-impact impact wrenches, although some models may have an impact mechanism. They have an angular design, where the spindle is located at a right angle (perpendicular) to the body. Pneumatic ratchets develop low torque values and are used to work with small fasteners. They are relevant for use in hard-to-reach places, for example, in the engine compartment of a car.
Maximum torque
Having enough torque to remove fasteners is the most important factor when selecting an air impact wrench. Removing bolts and fasteners of various sizes requires a certain amount of torque, which varies from case to case. Knowing the recommended parameters in your field of activity, you can easily select the necessary model.
Below in the table you will find the most suitable parameters for choosing a pneumatic impact wrench for unscrewing different bolts and nuts.
For frequent or professional use, we recommend choosing a more powerful model (yellow in the table).
If the air impact wrench cannot loosen the bolt or nut within 5 seconds, then you need to use a more powerful tool or apply penetrating lubricant to the threaded connection and try to unscrew the fastener again.
Connection square size
This parameter is closely related to the torque characteristic. The higher the torque, the larger the size of the connecting square the pneumatic impact wrench will have. The size of the tool's connecting square must correspond to the size of the square of the impact sockets, extensions and other fitting tools that you use. In some cases, it is possible to use adapters.
The most common are 1/2" square drive impact wrenches, which are suitable for most applications.
What to look for when choosing a pneumatic impact wrench
- If the user often has to deal with problematic hardware, that is, rusted/soured, etc., it is best to give preference to the so-called air impact wrench . The main difference between impact devices and non-impact (static) devices is the presence in the former of an additional “hammer” on the drive shaft , which creates an impulse when rotated.
An impact wrench can easily handle even the most challenging fasteners.
- Advanced air impact wrenches give the user the ability to customize the amount of torque . The force regulator usually has 3 positions: minimum, medium and maximum. The ability to adjust the torque makes working with hardware efficient and safe. With increased torque, the impact wrench becomes more productive than ever, easily unscrewing even rusty bolts/nuts. By reducing the torque, the likelihood of thread failure and fastener breakage is reduced.
- Experienced specialists always pay attention to cabinet materials . The most prestigious, and therefore expensive, are pneumatic impact wrenches with a titanium alloy body. Such models are incredibly durable, they are designed to work in the most intense and loaded conditions.
Cheaper impact wrenches are made in an aluminum alloy body. There are models with a plastic or composite shell. Such impact wrenches are much more modest than their titanium counterparts, but their potential is quite enough for an ordinary workshop or assembly line.
How to choose a pneumatic impact wrench for a compressor
Air flow and operating pressure
Before choosing an air impact wrench, carefully look at the characteristics of your air compressor in order to select the correct air impact wrench for the compressor. It is assumed that the average air compressor should produce 30%-50% more air than the entire connected tool consumes. For example, if a pneumatic impact wrench consumes 150 l/min, then it will work optimally with a compressor that produces about 200-225 l/min. As a rule, most models operate with an air pressure of 6.3 BAR, but there are impact wrenches with an operating pressure of 8.4 BAR. Some angle pneumatic impact wrenches (pneumatic ratchets) operate with a pressure of 3 BAR. The technical description of the pneumatic impact wrench indicates its operating pressure and the amount of air consumed.
As a general rule, the larger the compressor's air reservoir, the longer it will run, since a larger air reservoir will be depleted less often than a smaller reservoir, meaning the compressor motor will not be constantly running, pumping air non-stop.
Drive shaft speed
Otherwise found as rotation speed, measured in the number of revolutions of the working shaft made per minute without load. The higher the rotation speed, the faster the air impact wrench works. Almost always, higher performance of this parameter means lower torque from the impact wrench. Most people prefer to focus on the maximum torque value rather than the shaft speed.
Case Features
Type of shell
Pneumatic impact wrenches are divided into:
- Pistol;
- Corner
- Direct.
Pistol housings have impact wrenches with a connecting square from 1/4 to 3/4 inches. Can be used with one hand. Pistol body impact wrenches are the most popular.
Angled models have low torque, so they are used for working in hard-to-reach places, for example, in the engine compartment of a car.
Straight models have high torque characteristics and decent weight, as they must unscrew large threaded connections. Such impact wrenches have a connecting square of 3/4 inch or more. Due to the weight, each straight impact wrench model is equipped with an additional handle, so operation will require the use of both hands of the operator.
Housing material
The impact wrench can have a metal, aluminum or composite body.
Pneumatic impact wrenches with a metal and aluminum body are more resistant to careless use, such as falls, and are resistant to dirt or accidental collisions with cars. Of course, such models weigh more than impact wrenches with a composite body. Most models have a rubberized casing.
Due to the use of composite materials, the weight of the impact wrench is significantly reduced, but such models are more susceptible to external contamination and are sensitive to careless use.
Case size
A physical characteristic of a wrench that affects the ability to use the tool in hard-to-reach places. Typically, smaller impact wrenches have less torque.
The smaller the tool, the better it works in hard-to-reach places. The downside is that smaller models have less torque. This is a “slim” choice in which you will find a tool with the size and power you need.
Additional handle
Found in impact wrenches with a connecting square of 3/4 and 1 inch. The presence of an additional handle is due to the large weight of the tool.
Drive shaft length
There are models with both short and extended working shafts. The presence of an extended shaft makes it possible to work with fasteners that are recessed in hard-to-reach places, for example, in the steel rim of a cargo wheel. As a rule, powerful air impact wrenches for trucks have an extended spindle.
Power adjustment
The presence of speeds allows you to control the output torque of the air impact wrench. Thus, using different speeds depending on power needs will help loosen or tighten threaded connections without damaging them. The number of speeds for unscrewing and tightening depends on the specific model of the impact wrench and is indicated in the description of the product card or shown in a separate picture. It is also worth paying attention to the reliability and convenience of the location of the speed switch.
Weight
There are models with different weights. For short-term use, weight is unlikely to be an important factor, but for long-term work, where fatigue inevitably sets in, it would be better to choose a lighter air impact wrench. Over long periods of use, a lighter impact wrench places less strain on the wrist, resulting in operator fatigue later.
Ergonomics and reverse switch
The ergonomics of the tool plays an important role when choosing a pneumatic impact wrench. Choose a wrench that fits your hand, has a comfortable grip, and is well balanced to reduce fatigue and strain during use.
The reverse switch must be located on the impact wrench body in such a way that it is possible to quickly switch the direction of rotation of the working spindle.
Equipment
Some models come in a plastic case along with popular impact socket sizes, extensions, fittings and lubricator. The plastic case makes it easy to store, and the set is cheaper than buying all the components separately.
Warranty, service center and availability of spare parts
Check the warranty period and availability of spare parts: rotor blades, spindles and other repair kits. Pay attention to the presence of a service center, since a serious and responsible company not only sells, but also maintains the equipment sold, both warranty and post-warranty.
For most models of AIST
Spare parts are available, and missing parts can most likely be ordered from the manufacturer. AIST also has its own service center, which repairs and maintains tools.
Country of Origin
Most models of pneumatic impact wrenches presented on the Russian market are produced in factories in mainland China and island Taiwan. Taiwanese air impact wrenches differ from their Chinese counterparts in the following:
- Made from quality materials;
- Have reliable internal mechanisms;
- Neatly assembled and free of loose parts and gaps;
- Resistant to long-term loads;
- Develop the declared power;
- With proper operation, they ensure a long period of maintenance-free use.
All models of AIST
and
MASTER
are manufactured on modern high-tech production lines of factories in Taiwan.
Price
In general, the cost of a tool depends on all of the listed parameters, but the most important characteristic when choosing a pneumatic impact wrench is the maximum torque. Once you've narrowed down your choices based on the torque you need, you can look at other options by comparing the differences between specific models.
Rules for applying lubrication
If for some reason you are unable to install a lubricator on your unit, then you can get out of the situation in the following way.
- Immediately before starting the impact wrench, you need to unscrew the hose from it and drop 3 to 5 drops of lubricant into the tool fitting.
- Next, you should return the hose to its original place and turn on the unit for a short time (thirty seconds will be enough). Thanks to this operation, the oil will be evenly distributed over all moving parts of the device.
Lubrication in this way must also be carried out before long-term storage of the tool. When using the unit in intensive mode, oil should be dripped into the fitting every 3-4 hours.
Although this method helps to extend the life of the impact wrench, it is very inconvenient. You have to interrupt work and spend time cleaning the tool from contaminants in the area of the fitting and preparing lubricant. Also, during the procedure, you should carefully ensure that no dust gets into the unit. It is for these reasons that it is recommended to install a lubricator in the system, which will always supply lubricant to the tool in a timely manner.
Summary
It is worth choosing a pneumatic impact wrench based on the power needs and specific use in a particular area. Buying a high-quality air impact wrench will be a wise and correct decision, since you will receive a reliable and convenient tool that will serve you for many years.
Pneumatic impact wrenches for car service centers and pneumatic impact wrenches for tire fitting of passenger cars and small commercial vehicles: 90140761 old. 90143075, 90141360, 90146120, 90147109, 90140968/KI-857-X, 90140967/KI-1450, 90141200/KI-857, 90141520, 90146138, 90141201/ KI-857.
Air impact wrenches for tire mounting of trucks and commercial vehicles: 90151661, 90151520, 90152214/KI-1635, 90162767-6/KI-1838A-6, 90166285-8-X/90162851-8, 90163451-8, 90163 315-8, 90162200, 90162441 -6/KI-1837-6.
After selecting and purchasing the model you are interested in, you need to familiarize yourself with the operating rules.
Do not forget!
It is worth considering that when tightening threaded connections with an air impact wrench, the risk of thread breakage increases due to the impulse function of the tool, so you should use a torque wrench for final tightening.
Remember that with air impact wrenches it is necessary to use impact sockets and socket inserts with bits made of Cr-Mo (Chrome-Molybdenum) steel, as this material is well adapted to shock loads. When worn out, it is important to replace the end attachments with new ones so that loose heads do not grind off the drive square of the shaft.
Operating principle of a pneumatic impact wrench
The pneumatic impact wrench is connected through a fitting to an air compressor, the pressure of which should not exceed the value specified in the operating instructions for the device. When the trigger is pressed, compressed air entering the rotor blades causes it to rotate. Through the frame and hammers, the rotation of the rotor is transmitted to the stop and the nut or bolt is unscrewed or screwed into its seat. If a lot of force is required to turn the nut, the stop does not rotate, and the hammers, while turning, are deflected back and engage with the stop. During the next revolution, the hammers gain inertia and, approaching the engagement, hit the stop in the direction of rotation. The blows are repeated until the nut begins to turn. Thus, the impact wrench allows you to quickly and easily unscrew and tighten tight bolts and nuts. Due to its light weight (no more than 2.6 kg), the tool can be held with one hand.
