The pneumatic nutrunner is necessary for fast unscrewing/screwing of threaded connections. Today there are many models of different brands on the market, so it is quite difficult to choose a suitable wrench for specific jobs. Let us look at what to look for when choosing a pneumatic wrench and take a closer look at the 4 best models.
The pneumatic nutrunner is needed, as is easy to guess, to tighten and loosen the nuts. When the master pulls the trigger, the compressor emits a jet of strong compressed air hitting the rotor cavities, which causes the rotor to rotate. The rotor axis drives a frame with 2 metal hammers which in turn move the wrench axis. Socket head fastened on the axis and screws on the nut required. The nuts are undone with the reversing function. Depending on the built-in mechanism, wrenches are divided into:
- Impact wrench. The rotating tools perform only rotary movements for simple shapes of fasteners;
- Percussion. The rotating action is accompanied by pulses, so that the fastener is screwed on particularly reliably;
- Pistol type. Pivots at right angles to the body axis. This is a classic, conventional tool with a balanced center of gravity
- Straight type. All axes are parallel. Makes it easier to work in hard-to-reach places.
How to Choose a Pneumatic Wrench
When choosing a pneumatic wrench, it is necessary to clearly determine the purpose of its use.
Angle or straight wrench?
The angled impact wrench is suitable for fasteners installed “on the side”. The body of the tool acts as a force arm in this case. It is easier to hold in your hand when working with heavy fasteners. Straight wrenches are cheaper, more familiar and easier to use.
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This parameter determines the power of the air tool. The higher the torque, the more difficult the fixings can be handled. The simplest wrenches need only 80-100 Nm of torque. Models designed for commercial vehicle fasteners are required to produce thousands of newton-meters. Peak values are only required for unscrewing to get the nut out of place. You don’t need a lot of force to screw it in. Over-tightened bolts, on the other hand, easily break across, tearing off the threads. And if such trouble does not happen, you need more power to unscrew it next time.
The no-load speed of the spindle is assumed to be determined by the power of the impact wrench. In fact, the speed is only an indication of the design. A powerful tool, for example, is capable of producing up to 7,000. Rpm, but it’s not speed that counts with the truck, it’s the power that counts. For this reason they have a high air consumption, but the idle speed is about 3,000. Rpm.
Working pressure and air consumption
The airflow is directly proportional to the power of the tool and may vary for equal working pressure in the pneumatic system. For example, at a standard pressure of 6.3 atmospheres, medium-power models consume about 150 liters of air per minute. This figure can exceed 800 liters for the “powerhouses”.
It is desirable that the pneumatic system is equipped with a compressed air preparation unit. This greatly extends the life of the impact wrench and requires the operator to monitor output pressure and lubrication.
The dimensioning of the impact wrench must match the technical characteristics of the compressor. Recommended pneumatic system requirements are always found in the tool’s data sheet. Model has to be chosen that compressor must be able to provide normal working pressure at the declared flow rate.
Spindle fit size (chuck, shank square)
Wrench power determines the dimension of the shank, which is usually given in inches. There are the following standards: 1, ½, ¾ inch, and less common variants. The more powerful the tool, the larger the diameter of the spindle. This is logical, because a square of small cross-section at high power simply can not withstand the load. It is important to pay attention to the fact that it is difficult to find a sockets for non-standard shank, you will have to buy additional adapter.
Quicker fasteners give way when unscrewing due to the jerk effect. Over, it is impossible to unscrew half of the nuts with a hammerless tool. That is why impact wrenches are always the first choice.
Adjustable tightening torque and reversing torque
Almost all modern models have a reverse on/off switch. This function makes it possible both to tighten the fasteners with high torque and to unscrew old bolts. But there are some models on the market without reverse. Their spindle only rotates to one side.
The tightening torque adjustment function is also common, but it’s the first thing that fails on low-quality models. It allows you to set the maximum force that will be applied to the fastener. Torque accuracy even of expensive brand-name tools does not exceed 10%. Torque wrench is better if error is to be reduced to zero.
Dimensions, weight and ergonomics
Tool weight is reduced by use of lightweight, high-strength alloys. There are some models on the market with a plastic body, but their quality is originally questionable.
Not only the weight but also the high torque makes one-handed operation with the heavy tool impossible. That’s why these models are fitted with an extra handle.
For convenience, pneumatic wrenches are equipped with rubberized grip surfaces on the body and handles, as well as a pivoting nozzle for air exhaust. The tool is used at different angles, and the rushing air flow directed into the ground picks up dust. Debris in the eyes and lungs. The ability to adjust the direction of the air nozzle will be an additional bonus.
The advantages of a pneumatic impact wrench
If you don’t know how to choose a pneumatic wrench and in general, whether it is worth choosing it, let’s analyze how it is better than other types of wrenches:
- Pneumatic screwdrivers are excellent for “Spartan” conditions, they are autonomous, i.E. Not dependent on outlets, they are not afraid of moisture and aggressive working conditions.
- They are quite hard-wearing and durable. It can be used for a long time without interruptions and will hold up. For professionals, this is very important. And the tool takes a very long time to wear out.
- Lightweight design. When you are pondering which pneumatic wrench to choose, pay attention to the weight of the product. If you plan to spend a long time with the tool in your hand, you will like this option. It does not have a heavy motor.
- Reverse function makes it easy to not only tighten, but also loosen or loosen the nut.
When selecting this tool, you need to understand the nature and intensity of the work you plan to do with it. Professional impact wrenches, for example, allow you to work regularly, but for short periods of time. And budget options can be used no more than a couple of times a week.
Pay attention to maximum nut or bolt size when selecting an impact wrench. The budget versions are usually suitable for M25 size parts, which is enough for daily use. Medium sized vehicles require the ability to work with parts up to 3 cm in diameter, and with heavy trucks need to use wrenches that work with nuts up to 5 cm in diameter.
How to choose an air screwdriver
Pneumatic wrench. Indispensable when working on threaded joints. Even the most complicated ones. Those already reliably “seized” by corrosion. Are no problem for the pneumatic impact wrench. About criteria and parameters for choosing a impact wrench in this article.
The pneumatic impact wrench
An air ratchet is a device which converts compressed air energy into torque. And not only does it apply rotational energy to the screw joint when it is operating, but also impulsive impact loading which makes it easier to loosen tight threaded connections.
How it works? This is quite simple. The compressed air from the hose connected to the inlet fitting enters the tool handle and is routed through internal channels to the turbine rotor. On its way it meets the following elements:
- Shutoff valve, the opening of which is controlled by the button (trigger) of the tool;
- Power regulator, which is a small cylindrical tube with holes of different diameter (nozzles). Each of these apertures is capable of passing through a certain volume of air, which determines the final power on the tool’s chuck shaft;
- Rotation direction switch, which determines one of the two air channels to supply air to the turbine blades (rotor) and, as a consequence, its rotation in one or the other direction.
The torque from the rotor shaft is transmitted to the wrench shank, passing through the mechanisms of the percussion-torque unit along the way During normal tightening/unscrewing of a screw joint, torque is transmitted from the rotor shaft to the tool chuck. If the socket head of the latter encounters any rotational resistance, the impact unit activates. Tangential impact (force vector of which is perpendicular to the chuck rotation axis) is additionally generated on the shank shaft due to their masses and inertia forces arising in the unit, helping to overcome the resulting rotation resistance forces of the tool.
The presence of an impact-rotating mechanism significantly increases the effectiveness of torque and reduces the risk of injury when unscrewing stuck threaded joints.
Type of impact wrench
Even though all impact wrenches are designed almost identically, there are several designs for different applications:
– Designed for tightening “blind” self-tapping screws and screws in wooden constructions. Distinctive feature of this type. Low torque values and high chuck rotation speed. Option for the pneumo screwdriver is to use it in a garage or small auto shop to work with threaded connections with a diameter of 6-8 mm.
Air screwdriver, due to its low torque, is the only type of tool that does not require special tools. It can be anything you like, but it must be the right size for the application. The more “torquey” types of impact wrenches require specialized heads made of chrome-molybdenum alloy (CR-MO). Typically colored black for easy identification in the toolbox.
- The classic air screwdriver. The most common tool type with a rather wide range of applications, from small car workshops to construction sites and industry.
- Angle impact wrench.
The axis of this type of nutrunner is perpendicular to the axis of the rotor and the hammer mechanism, which makes it extremely compact. Beyond the tightest and tightest spaces, bolt heads and nuts are easy to reach with the butterfly wrench. However, lower torque compared to legacy models, at the expense of compact size.
- The butterfly style impact wrench. Ultra-compact member of the family of impact wrenches. Named for the similarity of the control buttons to the wings of a butterflyflyflyfly.
Particularly suitable for the garage or small auto shop. Power characteristics allow to work without problems with fasteners with diameter of 8-12 mm.
Listed below are the main features of the air screwdriver that directly influence the choice of tool.
Parameter that has a direct impact on the maximum size of the fastener that can be handled efficiently with an impact wrench. The higher the value, the larger thread diameters can be served with it. For example, impact wrenches with a maximum torque of less than 750 Nm can work on fasteners with a thread diameter of less than 18 mm without any problem. A pneumatic gun with a maximum torque of 1500 Nm is needed for work with 27 mm diameter fasteners.
Not all models have this useful option. Its presence extends the functionality of the tool and the boundaries of the application.
Screwdrivers are not like other screwdrivers in the way they are adjusted. With pneumatic tools, power is reduced by reducing the amount of air supplied to the turbine rotor.
Choosing an impact wrench is only half the battle. You have to learn how to use it correctly. Improper use can result in torn hardware or tool breakage.
I have been working at a tire changer for 9 years. Tried many pneumatic wrenches. Lately we have stopped at FUBAG IW-720 model. The lightweight gun can cope with any nuts on cars. Can not find faults in the work.
In the garage I bought a Metabo DRS 68 Set 1/2. I think the lack of impact function is a disadvantage, but the “hard-worker” can handle almost all nuts and bolts. Works for three years without failure. I consider the presence of an extension cord and cardan a big plus, because I can get under in hard to reach places.
The principle of operation of the air screwdriver
To understand the cause of tool breakage, you should understand how it is made (fortunately, the mechanism here is very simple). Pneumatic nutrunner consists of a nozzle, to which the air hose from the compressor is connected. Next is a start button, which directs the air flow into a cylinder with rotor and blades, untwisted by high pressure. Motor transmits rotary motion to the stop where nozzles for tightening nuts are installed. If the impact wrench is an impactor, there is a hammer mechanism between the stop and the rotor.
For clarity and understanding of the impact wrench, below is a photo and video of the tool in disassembly.
Expensive segment (from 8000 )
The high-end segment representative from JONNESWAY justifies its price perfectly. Works well with hub nuts and pulley bolts. Works great in tandem with 8-10 mm hose, especially with reinforced cord. The impact wrench has a rubberized handle that damps vibration and allows you to work longer without interruption. The best buy for the small garage or home garage.
Perfectly unscrews the nuts at a pressure of 10 atmospheres. This is an important point, because with other pressure values can not cope with the fasteners. The package is small, it includes only the connector and instructions. Powerful and reliable. A great garage and car service option for six months or more even with regular use.
The small but powerful G1285 is the right choice for domestic and professional use. Can handle bolts 22-24mm. Maximum torque value of 1220 Nm. The impact wrench has a steel drive shaft that lasts a long time. Body is made of impact resistant material. Drop from one meter high.
What to look for when choosing?
In order not to regret the purchase, you need to consider the purpose of buying a wrench and what tasks it will perform. Check the following points before buying.
- Maximum rpm is one of the main parameters. The speed required will vary depending on the application. The domestic models have a range of 40-100 rpm, while the professional models have a range of up to 5000 rpm. For household purposes it is recommended to choose something medium: from 400 to 500 revolutions per minute.
- Battery capacity. This value determines how long the wrenches will work. The higher the value, the longer you will be able to keep the battery charged.
- Torque. The higher the maximum value, the more difficult nuts and bolts the impact wrench can work with. Available from 90 to 950 Nm. Household models usually have less than 600 N-m. 810 Nm and above is good for car repair, 440 Nm for general repair work. And models with a value of 250 H-m and below can be used for tightening small nuts on aluminum or thin metal, as well as for tightening thin plastic structures.
- Body material. The strongest and most durable body would be metal. Another option is a special reinforced plastic. Benefits from lower price and light weight. Hand does not get tired as quickly, but is inferior to metal tools in terms of reliability.
- Ergonomic. Before buying, you should understand how comfortable the tool will lie in your hand. Pay attention to the weight, location of controls, location of the handle. If the handle is located in the center of gravity, you will be less tired while working.
- Complete set. Look out for the useful extras that come with it. This will not buy some things separately, saving time and money. Wrenches can be accompanied by a carrying case, belt straps, wrist strap, carrying pouch, or various socket sizes. Large two-wheel drive system with extra battery pack for non-stop charging.
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