Many associate impact wrenches with car repair and tire change. While it is true that mechanics and rubber workers increase the productivity of their workshop by taking advantage of the benefits of these tools to easily remove bolts / bolts that would otherwise be very difficult to maneuver, the impact wrenches They also find wide application in other fields. Examples are the manufacturing, iron and steel, mining, oil, aeronautical, agricultural, construction industries and all those situations where a powerful wrench is needed to extract or place nuts and bolts or bolts.
The impact wrenches or, more appropriately, impact guns, as we know them today (that is why in this article we will use both terms as synonyms) they were introduced on the market about 75-80 years ago and as we can see in the figure below, the appearance they present does not seem to be very different from that of a drill, although beyond this, both tools work very differently. Let’s see why.
Pneumatic impact wrench
Impact Wrenches Operation
While a drill supplies constant rotational energy at a relatively high speed, a impact wrench is designed to provide a torque (or torque) raised at low speed.
Furthermore, the impact wrench does not even supply constant torque. Its performance could be understood as something very similar to the fact of placing a wrench on a nut or bolt that we want to loosen and hitting the wrench with a hammer, making it turn by short and gradual sections.
When the impact wrench energized, an internal “hammer” strikes against an anvil, which is connected to a square or hexagonal socket chuck at the operating end of the tool. This gives a rotation to the socket wrench connected to the chuck and that rotation is what is used to tighten or loosen the desired nut or bolt.
The great advantage of impact wrenches Above other similar tools is this hammering action, which achieves two important effects that a common drill lacks. First, it exerts more force than can be applied with a typical wrench, or even a torque bar. Second, the hammering action tends to loosen rust and other deposits that keep a nut or bolt attached to the surface and make removal considerably more difficult.
Impact Wrench Types
Currently, four types of wrenches / impact guns: 1) manuals, 2) those driven by compressed air or pneumatic and, like many other tools, the electrical. The latter can be 3) With cable, which we connect to an outlet, or 4) Without cable or wireless, powered by rechargeable batteries.
Next we will see each of these impact wrenches in more detail, but we will concentrate on the nuematics.
Manual Impact Wrenches
It’s about the wrench itself, which arose long before compressed air or electricity was available, when workers used a manual version of the current one impact gun, applying the same common wrench and hammer principle that we saw above. Even today, in modern models, these hand wrenches are useful for the home or hobbyist, as well as for simple and infrequent tasks.
In the figure below we see the appearance of a manual impact wrench, as well as its typical operation in an engine.

Manual Impact Wrenches
However, those who work in workshops and use these tools frequently will undoubtedly prefer the pneumatic or electric impact wrenches, which are much less time consuming and easier to handle.
Pneumatic Impact Wrenches
This is the most traditional and economical type, although it requires a air compressor to provide the compressed air that acts as a motive force to propel the tool. Since the air consumption of a pneumatic impact wrench it is quite high, you need a compressor of sufficient magnitude to supply the air effectively.
The impact wrenches Pneumatic boats come in different sizes and powers, from models that can be operated with one hand to those that require the intervention of two people, so each one is adapted to the needs of the user.
The pneumatic impact guns Today they feature an ergonomic design that reduces user fatigue despite many hours of continuous work.

Pneumatic impact gun wrench
What to consider when choosing to buy a pneumatic impact wrench?
As always, it will depend on the task at hand, however, these are some key points that are important to consider:
- Ergonomics: The pneumatic impact wrench is usually used for long periods or in situations where a good grip makes all the difference. Also, weight is key and that is linked to materials and components, which brings us to the next point.
- Durability: here the quality and composition of the materials prevail. The most durable ones usually have an aluminum body with some alloy to combine resistance with low weight.
- Insert: it varies a lot according to the task to be carried out, the most common being a 1/2 ″ or 3/4 ″ recess. In any case, there are accessories that allow you to adapt the fitting to the different measures with which you want to work.
- Connection: this is a key point that is directly related to the hose-compressor link. In different countries there are different inserts, for our part, we always recommend using “quick couplings” which simplifies the exchange between the different pneumatic tools.
- Air leak: Because it is a tool that works with air, the flow enters from the compressor, circulates to operate the impact valve and logically, in the end, it must be expelled. We are aware of designs that, to our surprise, have not taken into account the direction of the escape of air and have directed it to the body, or even to the face. During use, it not only becomes annoying, but also dangerous. It is advisable to choose an exhaust that tends downwards or that starts from the lower end.
- Regulation of force or torque: When using a hand wrench, the force of the user is what determines the torque, actually, depending on the application and in many cases on the specifications that correspond to the different nuts, bolts or bolts, it may be necessary to regulate the torque. It may seem, at first glance, a minor detail, however, it is key to doing a good job! In addition, the proper torque prevents breakage and damage to the part and the tool.
- Reverse functions: as in conventional screwdrivers, this function allows reversing the rotation by simply activating the mechanism.

Reversible pneumatic impact wrench
These are just some of the most important considerations when choosing to buy. pneumatic impact wrenches. However, we insist that the choice must always be conditioned by the specific needs of the task to be performed.
In conclusion, impact wrenches are ideal for inserting and removing both bolts and bolts. Therefore, if we are looking for a traditional tool that allows us to work for long periods of time, the pneumatic impact wrench it is an excellent option. On the other hand, if we need an impact wrench for more precise work and that can work at several different power levels, or if we do not have space to install a compressor, then a good alternative is to look for one electric impact wrench.
Electric Impact Wrenches
Although they have been replacing them with their wireless peers, many manufacturers offer corded electric impact wrenches. They provide similar performance to pneumatic impact wrenches similar in size, but only available in very limited sizes. We develop this topic in due course in this article.
User Review
( vote)