How to Choose a Wrench

A wrench is essentially a large and powerful wrench used to loosen / tighten any wrench connections. But unlike a conventional wrench, this type of tool, for example, even a manual wrench, is equipped with an option to control the force and torque of the nut.

How to Choose a Wrench

Wrenches are often used in industrial enterprises, but in everyday life they can find enough work, especially if the owner is a car enthusiast.

Wrenches: main types and types

A wrench, albeit a very highly specialized tool, but the scope of work, as well as their scope, is quite impressive, and therefore, for different purposes and tasks, you can choose one of the types of this tool.

Types of Wrenches

So, wrenches by the principle of work are:

  • Pneumatic. This is the most compact, in size, view, with average characteristics in terms of power, speed and accuracy of operations. Indispensable in small workshops and service stations, especially. Tire fitting;
  • Hydraulic. Have the highest efficiency, do not have vibration and are distinguished by a large working resource and wear resistance. But this is also the most cumbersome. The size and rather heavy weight of these devices turn them into a purely professional tool that is used at industrial enterprises, large car services, etc.;
  • Electric. These are high-speed and accurate tools, they have practically no vibration. They are divided into two subspecies: cordless wrenches and those operating from the network.

How to choose a wrench:

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Wrench Type: Straight or Angled

This division into types is based on the principle by which the spindle rotates in the machine: in straight lines, the axis of rotation of the spindle coincides with the axis of motion of the motor, that is, they are parallel, and in the corner, the axes are perpendicular to each other.

Due to such design features, these two types have significant differences in terms of tightening torque, namely its strength, in angular it is 10-20 times less. For example, you can compare 4500 Nm for straight wrenches, versus 120-150 Nm for angular. But to perform some types of work on loosening contaminated or problem nuts in hard-to-reach places. You can’t do without a corner apparatus, and such power, as a rule, is often enough in many such cases.

Pictured is a pneumatic impact wrench

Impact and “unstressed” wrenches

Depending on the principle by which the torque in the tool works, all wrenches can be attributed either to impact, to direct or static. The former, in addition to performing a simple rotational motion, also performs drums. Percussion instruments are equipped with an additional shock counting option, and some have an electronic system for controlling the operation of torque.


The strength of the shock effect directly depends on the torque, as well as the number of blades on the turbine and its size.

And, for example, a pneumatic wrench will be additionally dependent on the power of the discharge compressor. And, accordingly, if the tool itself is powerful enough, but the compressor has average parameters, then this will affect the impact force.

The impact wrench first starts working on longer impacts, but closer to tightening or to the moment of free unscrewing, moving to shorter ones. In the process of tightening the nuts, the greatest impact force is provided precisely at the end, when additional force is necessary to ensure greater reliability of the bolted connection.

How to Choose a Wrench

Some wrenches, regardless of their type or type, can be equipped with a reverse mechanism, as well as a torque regulator.

Wrench with nozzles

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Mechanical wrench

This is not just a variety, it is a special tool that does not apply to any of their types or types of wrenches and has a clear purpose. For working with truck wheels. Although they can be both percussion and conventional. But the principle of operation of percussion mechanical tools is somewhat different. The percussion mechanism is activated only in the event of a load in the form of a nut resistance. And structurally and externally, this wrench resembles a familiar kitchen appliance, and got its slang name. A grinder, for this reason. Its other name is a key-reducer.

Pictured is a pneumatic wrench

The irreplaceable assistant to the driver

Its important advantage is an independent mechanical working principle, compactness and mobility. Such a tool in the arsenal, for example, with a trucker is a guarantee of road safety and timely arrival at the destination. These wrenches are distinguished by both increased reliability and reliability. Manufacturers took into account the fact that their main purpose is to remove and tighten the wheels of trucks, that is, rather heavy equipment, therefore, exclusively alloy steel that has undergone special hardening is used for their manufacture.

But it is likely that such a tool can also be used in the household of a country house or cottage, at a construction site, to perform certain operations, etc.

Pictured is an electric wrench

How to choose a wrench?

A wrench, like any tool, is purchased to perform certain tasks, and it is the purpose for which it is intended that is the starting point of choice: the motorist, most likely, does not make sense to consider the option of buying professional equipment. And, for example, at a service station, a manual electric wrench may possibly cope with the work, although by the number of revolutions it will lag far behind a professional tool, but, in any case, it will fail very soon, since it is not intended for use in intensive production conditions.

Wrench kit

Attention to technical parameters

The choice should be determined by other parameters, such as tool power, battery capacity (only for electric cordless wrenches), the availability of options for adjusting the speed of rotation, effort. Preferably, the gear case is made of metal, there is free access to the “cheeks”, on the case and especially on the handle there are rubberized inserts to reduce vibration.


When choosing a household tool, the weight of the wrench may be the determining moment of choice, and special attention should also be paid to the location of the center of gravity.

It may be important to have additional options or combining the functions of two tools in one device, for example, an electric impact wrench with a drill or screwdriver.

Work pneumatic wrench

Wrenches for the auto industry STO and not only

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

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

Benefits of Pneumatic Wrenches

But pneumatic tools are a more suitable option, in addition, their power is much higher. The source of energy for them is compressed air, which, falling on the rotor, is then transmitted to the spindle. In auto repair shops, direct wrenches with reverse and torque control are most in demand, but for some operations it is better to have a second device. An angular one. It should be noted that the pneumatic impact wrench finds its application on the lines of the car assembly, but only direct varieties are used there.

Advantages of hydraulic wrenches

The scope of hydraulic types of wrenches is quite wide. This explains the wide range of these devices. In tire shops, a wheel wrench is used, in which the following principle is applied: through the ratchet element, the translational movement from the hydraulic cylinder located inside the housing is transmitted to the working mechanism.

Cassette and union wrenches

It should be noted that there are two types of hydraulic units: sleeve and cassette. The former are able to cope with the most complex bolted joints due to the power of the hydraulic drive. In contrast, a hydraulic cassette wrench is used to loosen the nuts in hard-to-reach places, if it is impossible to use the union option. Given the complexity of the work intended for hydraulic wrenches and their power, the housing is made of especially durable materials, often these are aviation alloys, which are characterized by increased strength with a small weight, and alloy steel.