Pneumatic torque wrench

Optimal torque control of your impact wrench

October 15, 2018.

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Originally pneumatic impact wrenches were designed to loosen tight nuts and bolts. Nowadays, however, mechanics use impact wrenches to tighten bolts, for example, on wheels, as this allows them to work more efficiently, safely and quickly. Here are some guidelines for torque management and tool performance.

Good torque control is essential for perfect bolt tightening (Measuring torque when changing wheels is covered in our blog), so your tools are designed with a range of features to control tightening force and torque for your specific application.

For example, bolts usually require more force to loosen, as they may have rusted or become jammed. Conversely, tightening the bolts requires less power. in this case, more precise control and control is needed to avoid overtightening, stretching or breaking the bolt.

Yann Pasco. Global Business Development Manager. Automotive Services

The power of a pneumatic tool depends on the volume of air in the engine, and based on this, there are two ways to adjust the power. The first is to adjust the air pressure, the second is to directly influence the air flow rate by choosing a suitable air compressor or using a hose of the required diameter.

Most pneumatic tools on the market are rated for optimum performance at 90 psi. in / 6.3 bar Operators must use an air regulator to measure pressure when connecting the tool to the compressor.

The FRL device (filter, regulator and lubricator in one) limits the air pressure to the instrument and allows you to regulate the pressure in the hose. This allows for a more accurate power setting. therefore, mechanics should use this regulator to adjust the air pressure and achieve high accuracy. If the pressure on the tool does not coincide with the recommended, then its performance will undoubtedly be lower than expected.

Over the years, instrument designs have evolved to more accurately control air flow. In the first half of the twentieth century, the early classical models were equipped with a special lever, the release of which reduced the air flow inside the instrument. These primitive impact wrenches used a simple technology, they could be operated with one hand, but they could not provide high accuracy of adjustment.

Over the past ten years, special attention has been paid to the ergonomics and controllability of the tool. Most tools were still designed for one-handed operation, and their clever design allowed the operator to change direction of rotation and adjust torque with one hand.

Nowadays, the highest level of precision and ergonomics of the instrument is at the forefront. Instruments are designed with the ability to more accurately adjust the air flow. and therefore the torque. The innovative design of the latest impact wrenches increases the efficiency of the mechanic. for example, no need to move the tool to control the working power, since the control panel is located at the back of the tool, freely accessible.

There is no one-size-fits-all tool for every application. On the contrary, the best tool for the job is one that meets the mechanic’s needs, habits and comfort. From the huge range of impact wrenches available today, there are several criteria to choose from, and one of the most important criteria is the degree of precision power and torque control you need.

Yann Pasco. Global Business Development Manager. Automotive Services

One last thing to consider: the location of the tool on the air line (at a small or large distance from the compressor) also affects the pressure applied to the tool. Accordingly, more or less air must flow into the instrument, depending on the specific task, and this can be easily adjusted thanks to the capabilities of modern precision instruments.

Pneumatic Impact Wrench (Air Tighten Fasteners)

Compact and lightweight compressed air tool. Has gained immense popularity in car services, industry and everyday life. Capable of delivering impressive torque compared to electrical counterparts, while being less prone to breakage, thanks to a simple, monolithic mechanism. In this article, we will tell you how an air impact wrench works, what tightening adjustment is, and also tell you what to look for when choosing this tool.

Pneumatic torque wrench

Most modern impact wrenches are equipped with a torque adjustment feature. The main purpose of this function is to prevent fasteners from overtightening, breaking the thread or head. The adjustment will be useful for tightening relatively small nuts and bolts with a high torque tool. The fastener on the M8 will most likely be damaged if it is tightened with a tool without a regulator, with a maximum torque of 1000 Nm.

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The principle of operation of a pneumatic adjustable nutrunner is to restrict the air supply, thereby reducing the torque. For example: if on a Fubag pneumatic impact wrench at 900 Nm, set the mode number, its torque will decrease to 450 Nm, which will allow you to confidently tighten the M14 fastener. The number of modes on different instruments may vary, but on average there are from 3 to 5 of them. Information about the operating modes is indicated in the documentation attached to the tool. Each individual device has its own characteristics of regulated powers.

Working principle of pneumatic impact wrench

Like any pneumatic tool, a pneumatic impact wrench operates on compressed air from a compressor. Bypassing the hose connected to the wrench, air enters the device and begins to spin the rotor blades, which transfers rotation to the spindle (stop), the attachment, and finally to the fasteners. The reverse function changes the direction of the air flow in the tool, as a result of which the direction of rotation of the rotor changes, and the nut is unscrewed in a few seconds.

By type of work, pneumatic impact wrenches are impact and non-impact. The presence of an impact mechanism in the nutrunner increases its torque, but at the same time, the risk of breaking the thread or bolt head increases. The shock-rotational movement is created using a special hammer mechanism located in front of the spindle. Devices without impact function often produce less rotational force, and are mainly used when working with fasteners up to 12 mm.

Going deeper into the details, you can outline the device of a pneumatic wrench as follows. Inside the body of the tool there is a rear panel, a cylinder with a rotor and blades, an impact mechanism, a stop. On the outer part of the body there is a start button, a connection for connecting a compressor, a reverse and a regulator (on most models).

To current or future owners, with material where we tell and show how to carry out maintenance and repair of a pneumatic wrench.

How to choose a pneumatic impact wrench

  • Scope of application. Determine for yourself in which types of work the tool will be used. Whether you are looking for a pneumatic garage nutrunner, a compact vent mount or a large truck wheel unscrewing unit.
  • Nut dimensions. The more compact the fastener, the less tightening force it requires. If you have to twist nuts with a thread size from M6 to M10, a 1/2 landing square will do. The 3/4 square impact wrench is suitable for fasteners with M10. M18 threads. For large nuts, a 1-inch square is optimal.
  • Torque. Based on a certain type of work, a tool is selected with a suitable torque indicator, which usually ranges from 300 Nm to 3000 Nm (excluding the giants of the industry). The wheels of a passenger car can take off at 300-400 Nm, Kamaz wheels at 800-1000 Nm, and extremely loaded joints will yield only to a tool with an indicator of several thousand.
  • Tightening regulator. An important factor that adds versatility to the tool. The adjustment expands the range of fasteners to be screwed in, but on pneumatic wrenches it has an error of 10%.
  • Device weight. Long-term work with a heavy tool with vibration can make life quite difficult. If you choose a pneumatic impact wrench for a garage and small household chores for a few minutes a day, then a unit with an all-metal body will do. For longer use, it is better to take a lighter tool, with a body made of composite materials.

Compressor for pneumatic impact wrench

The most important equipment necessary for the operation of a pneumatic tool is an air compressor. This device, with the help of an engine, injects air in itself and directs it to the instrument through a special hose. Let’s take a look at how to match a compressor to an impact wrench to meet all your needs.

  • Pressure. The force of the output of compressed air depends on this characteristic, and therefore the performance of the tool. For most medium impact wrenches, a low pressure compressor that produces at least 6.3 atmospheres is sufficient.
  • Maximum productivity. An important indicator on which the pace of the tool depends. If the flow rate of 360 liters per minute is indicated on the pneumatic wrench, and the compressor pumps only 330 liters during the same time, you can forget about uninterrupted operation in such a bundle. Compressor performance should be higher than the needs of the wrench.
  • Receiver volume. A rather controversial indicator that determines the duration of the autonomous operation of the tool, in the absence of constant air pumping. Compressors with a small air volume (50 l) quickly lose pressure and for continuous operation of the tool, they must constantly pump air. With more impressive volumes (100-200 liters), the equipment can rest a little, despite the continuing operation of the pneumatics. For convenient work in a home workshop, a compressor for a wrench is enough for 100 liters.
  • Connection type. To deliver compressed air to the air impact wrench gearbox, you need a special sealed hose that can withstand the pressure being applied. Before purchasing such a hose, you should find out which fitting size it fits (1/4, 1/2 or 3/4). The manufacturer indicates this data on the instrument itself, in the documentation or on the box.
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Device and principle of operation

Any pneumatic wrench is shaped like a gun with a start button and is connected to the compressor using a hose through which air enters. The body itself can be made of plastic or metal. The latter is considered the most reliable, since heat is removed faster and the pneumatic wrench does not overheat.

The force of the compressed air drives the rotation mechanism, and the head tightens the fastener. There is a special screw on the handle with which the air supply is regulated. This provides a better twist.

Pneumatic wrenches

  • A rich package expands the capabilities of the tool

Pressure: 6.3 atm

Air consumption: 142.5 l / min

pneumatic, torque, wrench

Max torque: 720 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

  • High torque for working with trucks and heavy machinery

Pressure: 6.3 atm

Air consumption: 198 l / min

Max torque: 1200 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

  • Lightweight 2.7 kg combined with a high torque of 1200 Nm

Pressure: 6.3 atm

Air consumption: 266 l / min

Max torque: 1200 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

  • High tightening speed, maximum torque is reached in 3-5 seconds

Pressure: 6.3 atm

Air consumption: 142.5 l / min

Max torque: 600 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

Pressure: 10 atm

Max torque: 3200 Nm

Chuck size: 1 inch

Chuck type: square with hole and friction ring

  • Torque 717 Nm. the best option for tire fitting

Pressure: 6.3 atm

Air consumption: 133 l / min

pneumatic, torque, wrench

Max torque: 717 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

  • Metal body guarantees durability and long tool life

Max torque: 1356 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

  • Compact model allows you to work in narrow and hard-to-reach places

Pressure: 8.2 atm

Air consumption: 230 l / min

Max torque: 1085 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

Pressure: 6.22 atm

Air consumption: 164 l / min

Max torque: 1200 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

Air consumption: 230 l / min

Max torque: 314 Nm

Chuck size: 1/2 inch

Chuck type: square with friction ring

Impact presence: yes

The pneumatic impact wrench is designed for quick tightening and loosening of nuts and bolts. Such a tool is used in car services, repair shops and in production.

Features of the

  • Pneumatic impact wrenches operate on the power of compressed air, so they can be used where there is no electricity, as well as in places with high humidity.
  • The absence of a motor makes the tool lightweight, so the user will not get fatigued during work.
  • The reverse function allows you to change the direction of rotation of the head to quickly unscrew the nut or loosen the connection.
  • To unscrew fasteners in a hard-to-reach place, an extension nozzle is used.

How to choose?

Choose an impact wrench or impact wrench, depending on your application. The latter allows not only to tighten fasteners, but also to quickly unscrew rusted nuts.

When buying, you should pay attention to the tightening torque of the tool. For different pneumatic impact wrenches, it can be from 30 to 3000 Nm. The higher this indicator, the more effort is made when tightening the fasteners.

Pneumatic wrench for tire fitting Intertool PT-1106

Pneumatic impact wrench with a set of heads Vorel 81101

Electric impact wrench Titan PUG450 LCD

Compact pneumatic impact wrench 1/2 Yato YT-09514

Impact wrench 1/2 Yato YT-09506

Pneumatic impact wrench for tire fitting 1/2 ” 1356 Nm Yato YT-0953

Manual mechanical.

They consist of a torque-amplifying gearbox enclosed in a housing and a drive handle. Scrolling it for 20-30 revolutions will turn the spindle only 1 full revolution, however, the torque is converted from 200 Nm input to 7000 Nm output, as in Intertool XT-0005.
The manual nutrunner grinder with a gear has a gain from 1/16 to 1/68, which is sufficient for evenly loosening the bolts of truck wheels, with socket heads up to 33 mm, without the risk of breaking the fastener rod.

Electric impact wrench Titan PUG300

Best Electric Impact Wrench with Torque

BISON ZGUE-350 is a tool with an adjustable tightening torque. The gearbox housing is made of aluminum, equipped with external holes, which allows you to easily replace the brushes that come with the delivery. The presence of a two-position start button allows you to change the direction of rotation of the spindle without lifting your hand from the handle. The electric motor of not the highest power. 350 W. allows the gearbox to produce a torque of 300 Nm and provides a spindle speed of up to the classic 2 thousand rpm. Reliable percussion mechanism produces 3 thousand beats per minute.

For ease of use, the model is equipped with an ergonomic handle with rubber anti-slip pads, and a 5-meter power cord eliminates the need for extension cords. The case for storage and transportation will have to be purchased separately, since the tool is delivered in a cardboard box.

Drive types

The wrench is a device for twisting and unscrewing threaded connections, the shape of which outwardly resembles a pistol with a handle and an elongated body with the main working units located inside.

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The device is indispensable for tightening. unscrewing a large number of nuts or servicing hard-to-reach connections.

The variety of types of these tools is great. They are classified according to various parameters, which determine the usefulness of the device and the ease of use in a particular case.

By the type of drive, the following types of tools are distinguished: electric, pneumatic wrenches and manual.

Electric. the principle of models of such a device is based on the rotation of twisting nozzles using an electric current.

These devices are distinguished by high power, speed of operation and absence of vibrations, while the power source can be a 220V network. this subspecies is called wired, or a built-in battery in a cordless nutrunner.

The battery is compact and portable, its use is possible in various conditions of high-altitude or summer cottage work, without access to electrical networks, however, as the battery discharges, the power of the device will weaken, which will need to be charged to continue functioning.

An electric wrench with adjustable tightening torque will allow you to quickly and efficiently service structures with complex and strong connections, unscrew or tighten numerous nuts and bolts.

Pneumatic impact wrenches require a compressor or a wall inlet to operate, since the rotation of the nozzles occurs under the pressure of compressed air.

This type of device is quite powerful, has a large torque and, at the same time, it is light, compact and safe to operate.

Since wall inlets in our country are just beginning to appear, and a compressor for household needs is rarely bought, pneumatic wrenches are more often used by professional car mechanics or builders to perform work tasks than by amateur craftsmen in everyday life and minor repairs.

The principle of operation of manual impact wrenches is based on a rotating movement carried out by a person to operate the impact wrench.

When using a hand tool, the small forces applied are converted into increased rotation by means of a multiplier that converts torque.

This type of equipment is reliable, easy to operate, autonomous and mobile, has a low weight and small dimensions.


  • Type. direct, shock, network.
  • Power. 0.4 kW.
  • Torque. 350 Nm.
  • Revolutions. 2 thousand rpm.
  • Impact frequency. 2 thousand beats / min.
  • Chuck: type. ½ ”, diameter. 12.7 mm.
  • Reverse. yes.
  • Speed ​​control. electronic.
  • Weight. 2.9 kg.

What to look for

When choosing a wrench, you need to pay attention to the following characteristics:

  • maximum torque value;
  • battery capacity and voltage;
  • tool weight;
  • ergonomic tool.

What you can ignore
Secondary characteristics that can be neglected when choosing a nutrunner are:

  • body and handle material;
  • the frequency of impacts during operation;
  • the presence of a reverse motion;
  • the ability to adjust the speed;
  • the presence of a storage case and the number of attachments;
  • the ability to set an automatic shutdown of the device when a certain torque value is reached
  • super fast battery charging.

What’s better

Choosing between an impact and a non-impact device, it should be remembered that the former are cheaper and will cope with small amounts of work with threaded connections in everyday life, the latter are much more expensive and are used to perform industrial tasks and professional repair work.

An additional function of the impulse device allows you to use the addition of the force of individual blows, control the force and torque, which significantly increases the efficiency and speed of work.

Strong impacts accelerate the rotation of the chuck, which is able to enter solid material and withstand its density.

Best 12 Volt Electric Impact Wrench

A compact but powerful example of the BORT BSR-12 impact wrench powered by a 12-volt DC network. The model is not designed for serious loads, but due to its characteristics it is one of the best solutions for motorists. The device can be powered both from the terminals of the car battery, and from the cigarette lighter, and even from a 12-volt mowing line of a computer power supply of suitable power. The torque of 350 Nm is sufficient to loosen and tighten the wheel nuts of passenger cars.

pneumatic, torque, wrench

Torque Gun Company jGUN™ Pneumatic Torque Gun Operation

At such a low price, Bosch was not without flaws. We are talking about poor quality lubrication of units from the factory. For this reason, after purchase, it is recommended to disassemble the wrench and apply additional grease to the rotating parts in contact with each other. Another disadvantage is the length of the power wires. Sometimes it is not enough, so you should additionally build up one and a half to two meters.


Perhaps this is one of the main indicators that you should be guided by when choosing an electric nutrunner. Too high a torque can damage the fasteners, while too low will simply not tighten the nut or bolt to the rated torque. For household models, the parameter is from 100 to 300 Nm, while the production tool transmits more than 500 Nm of torque to the spindle.


  • price and power;
  • weight and size;
  • 12-volt universal DC power supply;
  • case included.