Which Pneumatic Impact Wrench To Choose For A Car Service

Choosing a pneumatic impact wrench To speed up work with threaded fasteners, special devices are used, represented by impact wrenches. This article describes how to choose an air impact wrench.


The rotor speed determines the speed of work. This parameter can reach up to 8000 rpm. When using devices with a large value, caution is required due to the difficult control of the degree of tightening, which can lead to stripping of the thread, especially of small fasteners. The rotor speed is controlled by changing the compressor pressure. It is recommended to purchase a device with a rotation speed of 3000 rpm.

The torque determines the power of the impact wrench. At a small value, a weak tightening occurs, and the fastenings quickly weaken under the influence of variable loads. Excessive torque leads to overstressing in the thread, leading to its rapid destruction. The range of this parameter for impact wrenches is 30-6000 Nm, but for pneumatic models it is narrower (300-2200 Nm). For example, options with an indicator of 100 Nm and more should be considered, choosing for tire fitting. It must be borne in mind that the declared torque is only achieved in the main direction of rotation. Some devices are equipped with regulation, which usually includes 3-5 modes. Its principle of operation is to restrict the forced air, leading to a reduction in torque.

The spindle size is selected based on the fasteners used. So, for automotive parts where 25 mm thread fasteners predominate, a 0.5-inch spindle is required. The inch spindle is suitable for fasteners with a thread of 25-32 mm, one and a half inch for threaded diameters from 50 mm.

The characteristics discussed above are interrelated. So, nutrunners with high speeds are characterized by high torque, therefore, they are focused on large fasteners and are equipped with large spindles. It should be borne in mind that powerful tools require appropriate compressors and high costs, so their purchase is not always advisable. In general, for permanent work, it is recommended to purchase a compressor with a power reserve of 40%.

In the case of selecting a tool for the existing compressor, it is taken into account for the wrench what pressure and air flow it has. In the case of exceeding its needs, the compressor capacity is not achievable, the full power of the tool.

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Other parameters

In addition to the structure of the nutrunner and the operating parameters, ease of use is of great importance, which is determined, first of all, by such parameters as dimensions and weight.

By the shape of the body, pneumatic wrenches are classified into pistol and cylindrical. The former are more comfortable to hold in a horizontal position. The cylindrical shape is more suitable for vertical work, and the elongated shaft allows for work in hard-to-reach and deep places. Currently, the most common models of the first type.

In addition, there are corner models designed to work with side fasteners. Their arm represents the shoulder of force. Such wrenches are convenient for specific cases, however, for most jobs, it is impractical to use them due to their complicated design and higher cost.

In terms of weight, pneumatic wrenches are significantly inferior to electric models. For most options, it is 0.75-4 kg. Professional tools weigh up to 10 kg. The most modern nutrunners with bodies made of composite materials are about 2 times lighter than their conventional counterparts. However, keep in mind that lightweight tools are not always the best. Thus, high-power, low-mass models are difficult to hold.

Many models of impact wrenches are equipped with accessories such as handles and pads. The latter are very useful when working in cold conditions and also contribute to better retention in general. The side handle is especially important for compact tools to increase the tightening force.

which pneumatic impact wrench to choose for a car service

In addition, the main features of pneumatic impact wrenches can significantly depend on the manufacturer. It should be borne in mind that many little-known brands are characterized by overestimation of instrument indicators. In general, it is recommended to purchase expensive European models.

Finally, it should be borne in mind that for a nutrunner as for a specific tool, cost does not determine quality. The main selection criterion that determines all the parameters discussed above is the purpose.

Selection principles

The following are the main criteria for choosing a pneumatic impact wrench.

Wrenches: main types and types

The wrench, although a very highly specialized tool, but the volume of work, as well as their scale, is quite impressive, and therefore one of the types of this tool can be chosen for different purposes and tasks.

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How to choose the right wrench?

An impact wrench, like any tool, is purchased to perform certain tasks, and the purpose for which it is intended is the starting point of choice: for a car enthusiast, most likely, it makes no sense to consider the option of buying professional equipment. And, for example, at a service station, a manual electric wrench may cope with the work, although in terms of the number of revolutions it will greatly lag behind a professional tool, but, in any case, it will fail very soon, since it is not intended for use in intensive production conditions.

Wrenches for the car industry service stations and not only

Considering that in any car there are a lot of nut-bolt connections, then at car assembly plants, as well as in service centers, you cannot do without a nut wrench, sometimes not of one or even different types. But which one to give preference depends on several factors.

In this case, electric wrenches are used extremely rarely, primarily for fire safety purposes, since due to special conditions with an increased concentration of flammable substances, sometimes moisture and dust, if a spark occurs accidentally, a fire may occur.

Design features:

  • The presence of a reverse– is necessary not only for the implementation of the twisting process, but also for unscrewing. Since the reverse belongs to the most fragile part of the nutrunner, choosing a future device is from European-made models that will last much longer than models of Iranian or Chinese origin;
  • Tightening adjuster– is an expensive thing, therefore, it is worth looking for a wrench equipped with a regulator only if you really need it in the future. As a rule, tightening is carried out “by eye”. This gives an error of 20% on average, which will not significantly affect the quality of work. The tightening torque can also be adjusted by changing the volume of compressed air pressure at the inlet;
  • Square size– in any kind of tool, this indicator is proportional to its power and often does not require any upgrades. The optimal value is ½ “, and at high power of the device. 1”;
  • Angle head– the need for it directly depends on the type of task. An angle wrench will allow you to tighten bolts or nuts on the side surfaces. They are more compact and have a minimum tightening torque. The cost of such an impact air wrench will be an order of magnitude higher, so you should think about it before purchasing an angle type tool.
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Pneumatic impact wrench. How to choose?

Recently, only hand or electric tools were used to install threaded connections. Now, among the wide variety of the range of construction and repair equipment, pneumatic wrenches are especially popular. They have become reliable helpers when installing bolts, nuts and other fasteners. How to choose a reliable air impact wrench and not get confused in the variety of the instrument? Let’s figure it out!

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.