Impact wrenches

It is used for maximum tightening (or most effective loosening) of screws with the least effort. Its advantage is the combination of impacts and rotation, which guarantees its effectiveness.
The wrench is equipped with an air or electric motor, which effectively loosens or tightens screws with short and twisting movements. At low speeds, a high torque is created.
The mechanism consists of two most important parts. Hammer and anvil. The latter sticks out of the machine and a working tool is clamped at its end. For example, an impact socket or a bit.
The principle of operation is the repeated pulling and releasing of the spring on the hammer part. This releases the hammer and the accumulated energy hits the anvil during rotation (in the direction of engine speed). This is how the screw is loosened or tightened using an impact. It is possible to tighten with different tightening torques even in hard-to-reach places,
which is also helped by impact extension bats, joints and adapters.
The most common size of the wrench is a four-inch hexagon or a half-inch square.

If you have decided to buy an impact wrench, you need to consider whether you want a pneumatic, battery-powered or electric.
Its "power" is also important. For normal hobby use, when you only need to tighten wheel bolts a few times a year, a screwdriver operating
with values ​​of 200-300 Nm will be sufficient. On the other hand, professional machines can handle 3000 Nm. The recommended number of impacts is at least 3000 per minute.

Another important parameter is vibration. Modern and high-quality machines try to eliminate vibration to the lowest possible value so as to avoid unpleasant hand pain
during use of the machine.
In short, focus on the number of revolutions, maximum torque, power source and in case of battery-powered machines also battery voltage.
The weight of the machine, or LED lighting, protection against dust and moisture can also be an important aspect.
Your choice of power source (and the usability of the wrench in various situations) will also affect the price of the machine.

Pneumatic / air impact wrench
The impact wrench should have the same or slightly lower capacity than the compressor. It is powered by an air motor using compressed air. For its functionality and use, it is necessary to ensure a compressor with sufficient capacity, air distribution, for example using hoses, couplings and quick connectors.
3/8" hose is ideal for smaller wrenches suitable for limited space.
1/2" hose is a popular and common size for the home workshop.
3/4" hose is intended more for professional use.
1" hose is for commercial purposes, wrenches are heavier and have higher power.
Air wrenches are most often used in car repair shops.

Cordless/battery-powered impact wrench
The wrench is powered by an electric motor, but unlike an electric impact wrench, it is powered only by a battery. The ideal power should be between 400 - 600 W with a torque of 400 to 600 Nm. Unlike electric and pneumatic devices, it is independent of the range of the electric power or compressor. It is often supplied without a battery and charger. However, their construction is light and easy to handle. Therefore, they are gradually starting to replace pneumatic wrenches which are being pushed out, for example, from tire shops.

Electric impact wrench
The wrench is comparable to pneumatic and battery-powered wrenches. However, it depends on the power connection (length of the power cable).

SUMMARY
An impact wrench is a useful tool in places where it is necessary to exert great force with minimal effort, for loosening joints on steel structures, rusted screws and when changing wheels in tire shops. In addition to the power source, it is important to consider the performance and torque of the wrench.

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