How To Choose A Pneumatic Impact Wrench For A Compressor

How to choose a pneumatic impact wrench

How to choose a pneumatic impact wrench

how to choose a pneumatic impact wrench for a compressor

Nowadays, pneumatic impact wrenches find more and more widespread use in various fields of activity. If earlier they were used mainly in assembly plants and auto repair shops, now they are increasingly appearing in home workshops, since they can be used to easily and quickly tighten and loosen any threaded connections.

The principle of operation of the pneumatic impact wrench is based on the energy of compressed air. When the tool is connected to a pneumatic mower line or directly to a compressor and the trigger is pulled, the compressed air starts to rotate the rotor, which transmits the torque to the spindle on which the head for fastening is put on. All impact wrenches have a reverse function that allows you to change the direction of rotation of the spindle. Also, on some models of pneumatic impact wrenches there is a power regulator that allows you to limit the tightening torque.

Pneumatic nutrunners are lighter and more compact than many network and battery analogs, and also have a higher tightening torque. The absence of an electric motor allows them to be safely used in high humidity conditions, as well as near combustible materials. In addition, electric motors are more likely to fail under high load and intensive use. The pneumatics is devoid of these shortcomings.

Form factor

There are 2 main form factors of pneumatic impact wrenches: pistol type and straight type.

  • Pistol-type nutrunners are more familiar to a wide range of people, since they have ergonomics similar to most tools. As a rule, such models are used in everyday life and in car services. Such wrenches, as a rule, have an impact function and have a large reserve of torque.
  • Straight type nutrunners are more convenient for use in industries. They allow you to work in cramped conditions and in hard-to-reach places. Such a tool can be held with one hand, and the other to hold parts or use your hand as a support. The shaft of the model can be either short or long, which allows you to choose the model for the working conditions.


Now let’s talk about the characteristics of impact wrenches that you should pay attention to when choosing:

  1. Torque. This is the main performance characteristic of the impact wrench. The range of tightening torques for different impact wrenches can be from 30 to 3500 Nm (Newton meters). Different types of work have their own tightening torque standards, from which it is worth starting from when choosing a tool. If the tightening torque is too low, the screw connection may loosen and loosen. Otherwise, with excessive tightening torque, you risk damaging the threads and / or fasteners. For example, the tightening torque for the wheels of a passenger car is approximately 90-120 Nm. But if you try to assemble the frame of wooden furniture on a bolt with such a tightening, then there is a high probability of damage to the wooden parts. Too much force will hammer the wood and even lead to its splitting.
  2. Rotational speed. It is indicated for the idle run of the no-load tool. The higher the rotation speed, the faster you can twist and unscrew the required fasteners. For in-line production, speed is important.
  3. Impact function. This function is very useful if you need to unscrew rusted and stuck bolts and nuts. Also, when tightening large fasteners with a pneumatic impact wrench with this function, they do not need to be additionally “pulled”. Due to impulse shock movements, the fasteners are tightened tightly. However, it should be borne in mind that the impact function increases the risk of thread breakage during tightening (and in the case of excessive torque, doubling). And when working with fragile materials, shock loading can damage it.
  4. Spindle diameter. Everything is simple here: the larger the spindle diameter, the larger the size of the fastener the tool is designed for. Typically, this characteristic is proportional to the torque. For example, for small bolts and nuts up to 16 mm in diameter, the spindle diameter is ΒΌ “, and for the tire fitting of trucks, 1”.
  5. Air consumption. Here, too, everything is quite transparent and interconnected: the greater the torque and rotation speed, the more air is required for the operation of the pneumatic tool. Large pneumatic impact wrenches can be powered by a small compressor, but in this case it will work without rest and will fail very quickly.
  6. Operating pressure. Together with the previous point, this characteristic must be taken into account when choosing a compressor. If the output pressure is insufficient, the wrench will still work. But at the same time he will not be able to reach the specified parameters of torque and number of revolutions.

On our website you can find a large selection of impact wrenches for different tasks. We will be happy to help you choose!

Pneumatic wrenches

Professional pneumatic impact wrenches for tire fitting

An impact wrench is a highly targeted tool that simplifies the process of unscrewing and tightening fasteners in a car during repair work. It saves time and improves the efficiency of repairs by 1.5-2 times.

The pneumatic impact wrench is one of the most popular types of tools. It runs on compressed air, which is supplied to the twisting mechanism by a blower. This tool is ideal for service stations and tire changers. It is lightweight, reliable and easy to use.

The main advantage of the pneumatic impact wrench is that it can be used even when working with fuel and lubricants. It works exclusively on mechanics and does not generate sparks, therefore it is 100% safe.

But it should be borne in mind that for good tool performance, you need to use clean air without exhaust gases and dust. Otherwise, its service life will decrease by 1.5-2 times.

The pneumatic impact wrench should not be connected to a compressor that exceeds the capacity of the tool. Excessive pressure in the system can lead to complete damage to the device, which will be difficult to restore.

It is also necessary to carefully monitor the amount of lubricant in the mechanism. Lack of oil leads to poor performance and increased wear.

With active work, you need to disassemble the instrument every few weeks and clean the air ducts from dust. This will prevent clogging of the system.

What are the types of pneumatic impact wrenches and how to choose a reliable one?

On the tool market today, there are 2 main types of impact wrenches according to the principle of operation:

  • Shockless. Loosening and twisting of the fasteners is carried out using a stable load with a well-defined effort.
  • Impact. The tool tightens and unscrews the nuts with a series of impacts. The pressure on the fastener is applied unevenly, which allows you to unscrew even tightly tightened and stuck nuts.

Impact wrenches are quite suitable for basic repair work, but for a service station and tire fitting, experts recommend using an impact pneumatic wrench, because you often have to deal with stuck nuts.

Straight and angle wrenches are also distinguished by the shape of the body.

An angle wrench is also popularly called a “pistol” because of the shape of the handle with a trigger. Such a tool is very convenient when working on weight and for loosening-twisting fasteners in hard-to-reach places. But such devices have limited power. Up to 150 Nm. It is quite enough for working with passenger cars, but for trucks something more powerful is required.

The straight pneumatic tire wrench delivers much more torque. In some models, this figure reaches 4500 Nm. This is a full-fledged pneumatic impact wrench for trucks, with which you can even mount a tower crane. It is most convenient to work with direct devices on stands and workbenches. True, the price of such pneumatic impact wrenches in Ukraine is quite high.

We evaluate the design ergonomics

Decide which shape of the case will be suitable. Both impact and non-impact pneumatic wrenches are divided into two types.

When buying, pay attention to the weight of the tool. Compared to networked pneumatic tools, they are quite lightweight (from 0.75 to 4 kg). There are also professional pneumatic impact wrenches, the weight of which can reach 10 kg. They are used in industry, mechanical engineering, shipbuilding, etc.

Choosing a pneumatic wrench

How does a pneumatic impact wrench work? It connects to the compressor, and when the user applies the nozzle to the head of the fastener and pulls the trigger, compressed air is fed through the hose to the inside of the device and starts rotating the rotor. That, in turn, transmits a rotational action to the spindle, and the fasteners are screwed into the material. The reverse function allows you to change the direction of air flow to the rotor, and, therefore, the rotation will be carried out in the opposite direction. This way you can unscrew the nuts and bolts. As a rule, this procedure takes only a few seconds, which significantly increases labor productivity compared to the manual method.

This is far from the only reason why many manufacturing enterprises and repair shops use pneumatic wrenches as technical equipment. If you choose between a network and a pneumatic device, the latter will have much less weight and dimensions (with similar characteristics). In addition, the absence of an electric motor makes pneumatics absolutely safe when working in conditions of high humidity, dustiness and concentration of flammable substances. Spark formation, electric shock to the user, as well as overheating and engine breakdowns during intensive operation are excluded.

If these are the requirements for your tools, then the pneumatic impact wrench is what you need. It remains only to choose the one that will meet the needs of your company. What should you pay attention to when buying? Let’s tell you more.

How to choose a pneumatic impact wrench for a compressor

Receiver volume

Shows the compressed air supply in liters. The volume of the receiver depends on the compressor capacity and the nature of the air consumption. It will take about 2 minutes to pump a receiver of 50 liters with an engine capacity of 150 l / min to a pressure of 6 atmospheres.

Consider, for example, the Prebena Vigon 300 compressor.

  • Receiver volume: 50 liters
  • Productivity: 300 liters per minute.
  • Working pressure 6-8.5 atm.

Adjusted for performance, it comes out about 240 liters per minute. The compressor is pumped from zero to full readiness in about 1 minute 20 seconds. If you connect a pneumatic screwdriver with a working pressure of 6 atmospheres and an air flow rate of 200 liters per minute, then we can say that this tool can work with this compressor. The working pressure is the same, and the compressor capacity is higher than the need for the screwdriver.And when you try to connect an impact wrench with a flow rate of 500 liters per minute, it turns out that the performance of our compressor will be 2 times lower than the need for the tool. This means that the compressor will be able to provide the working pressure of the tool, but only for short periods of time between compressor starts. For the constant operation of the tool, a more efficient compressor is required.

Air consumption

The higher the air flow rate, the more productive the tool is. But to keep such a powerful air tool running, a more efficient compressor is needed.


Tool selection options

Compressor parameters


Working principle of pneumatic impact wrench

The power source in the wrench is compressed air from the compressor, which enters the tool motor through the reverse and the nodal parts of the trigger. The rotor transfers the resulting movement to the flywheel located in the impact system of the wrench. The flywheel does the work of a conventional clutch. When the maximum resistance is reached, the working parts of the equipment stop, but the roller continues to rotate, forcing the impact mechanism to turn on.

Special regulators help to set the required parameters of tightening force, torque and screwing speed. They also control the operation of the instrument as a whole.

The advantages of the nutrunner include its high reliability and durability in operation. The tool body is always protected from aggressive media and excessive moisture levels. The air impact wrench is characterized by high wear resistance, minimal noise or vibration levels and increased productivity. Therefore, it is ideal for professional use for a long time, as well as for high workloads.


  • Idle speed– this is the main criterion according to which the power of the equipment is selected. Experts recommend purchasing a tool within 3 thousand. 7 thousand revolutions per minute;
  • Torque– determines the strength of the apparatus. On the construction markets, nutrunners with a torque value from 500Nm to 6000Nm are presented. The optimal value of this indicator is considered to be 3000 Nm. To work at a car service station, 1500-2800Nm will be just right;
  • Air consumption– especially important when selecting a pneumatic wrench for a specific compressor for a car service. Here it should be borne in mind that the receiver may be too small to provide the instrument with the necessary volume of air. This can lead to power losses. Standard models with a torque of 500-900Nm will consume in the range of 140 liters per minute. When working with a nutrunner, care must be taken not to exceed the pressure (normal pressure is up to 6 bar).

Types of pneumatic impact wrenches and device features

Before disassembling the main design features of the pneumatic impact wrench, it should be noted that it is divided into two types:

  • Impactless pneumatic wrench. Used when working with fasteners of simple shapes that do not require special professional skills and efforts. Such a tool allows you to work with maximum efficiency and there is no risk of the nut breaking off the thread;
  • Pneumatic impact wrench. Used for more significant and large volumes of work. For example, with rusted and stuck bolts. It is the percussion mechanism that is often used when working on a conveyor belt.. During construction, in factories or other large-scale works, as well as in domestic conditions.

Today, due to technical modifications, many models of such equipment are distinguished. At the same time, the device of the pneumatic wrench remains practically unchanged and has a rather simple design. The main components of a pneumatic impact wrench include:

  • Shock system. Can consist of a cam clutch, cam, pusher, roller and spring mechanisms, pins and a flywheel with a roller;
  • Pneumatic engine. Most often, the tools contain motors of a rotary six-blade type, installed in the body;
  • Reverse unit. Together with the trigger is located in the tool handle;
  • Launcher. Is in the handle;
  • Equipment case

Some modern models of the pneumatic impact wrench are additionally equipped with a handle that can be placed in two or more different positions in relation to the body part. This small addition is able to provide more comfortable operation of the tool during operation.