Electric wrench: principle of operation and overview of popular models

If you ask an unknowing person about what a wrench is needed for, then almost everyone will answer that the main purpose of the device is to tighten the nuts. Even many professionals argue that an electric wrench is one of the options for a screwdriver, the only difference is in the types of cartridges. But this is not entirely true. There are some similarities between an electric wrench and a corded screwdriver. But in fact, these are different tools, very different from each other.

Let's compare the two tools.

Many impact wrenches are impact devices, which already distinguishes the device from the screwdriver. And if in hammer drills the blow is carried out along the length of the barrel, then in wrenches - in the direction of movement.

There are a lot of percussion structures in the world. But they all work according to the same scheme:

• the clutch rotates the chuck until the operator begins to exert pressure on the tool;
• the driving element stops working in conjunction with the chuck, accelerates strongly, but does not complete rotation and hits the chuck (the latter, in turn, does not make any movements);
• due to the fact that the driving element is quite weighty and rotates at high speed, a moment of force arises along the barrel, due to which the fixed bolts move.

The main element of any wrench is the clutch. The final price of the device depends on the shock coupling. It is an indicator of reliability. In budget lines of devices, the coupling is not installed. On some devices, it can be turned off - then the device will turn into a standard screwdriver. These products are very expensive. And if you need a device not for professional activities, but for home use, then it is better to buy a screwdriver and a wrench separately. For versatility, the manufacturer asks for a very high price.

The next important indicator of the wrench device is torque. That is why very powerful batteries are installed in battery-type devices. If you purchase these batteries separately from the instrument, then they will cost you dearly. Because of this, most wrench manufacturers release their product without batteries as standard. All buyers rejoice at the low price, and after purchase they discover that the new battery costs the same as the device itself.

Summing up the above points, you can see that the range of directivity of impact wrenches is much narrower than that of screwdrivers or hammer drills. It makes sense to buy a gadget if you are not a fan of car services. With its help, you can inspect the car yourself. It can be especially useful in a garage. Automotive bolts cannot be removed with a wrench or adjustable wrench. All the craftsmen faced a situation when the nuts and bolts had not been loosened for a very long time, therefore they are in a "frozen" position.In this situation, the impact wrench will also be indispensable, since it is very difficult to unscrew it manually.

It is not recommended to use the instrument at home for other purposes. Since it will only aggravate the situation due to the lack of a regulator. You cannot detach the clutch here. And at high speeds, the device can "demolish" the thread.

The wrench is very handy in the professional field. It comes in handy in maintenance services, tire fitting and car dealerships. In these situations, it is difficult to overestimate the importance of the device: it is very powerful and partially has functions of dust and moisture protection.

The device is often used in the field of field technical support, it is especially common among operators who are engaged in the assembly and disassembly of iron structures. The device is popular in industry and factories.

Let's start with the most important characteristic of the device - the moment of force. The higher this indicator, the larger the nuts the tool can move. Before purchasing a device, you need to find out for yourself what purpose it will be used for. If you decide to unscrew the small bolt with a powerful device, then it will simply break the thread. Therefore, experts recommend starting from the approximate diameter of the nut.

For nuts of size 12, a device with a torque of 100 Nm is suitable. The size 18 nuts unscrew the device well at 270 Nm, and the size 20 is tied with a torque of 600 Nm. This is the most powerful unit to date.

The type of chuck depends on the size of the nuts to be loosened and the torque of the tool. The quarter-inch hex chuck is usually installed in very weak fixtures. They work in tandem with flat or sacral bits (sizes 1-3) and with nut (sizes up to 12). M12 heads are often found in mini hammer drills.

Less common types are 3/8 "and square (0.5") chucks. The latter is the most popular among the M8-M12 heads. The square version is used in conjunction with very large nuts, which are found in the repair of trucks or during the assembly of large iron structures. Many manufacturers, in addition to the standard configuration, put several adapters as a bonus on less popular cartridges.

The performance of the tool can be indicated by the maximum number of rotations per second. This indicator is not very much in demand when working at home, but it is a very important point during installation work in factories, where the tool almost never turns off. All other buyers can ignore the RPM. You just need to know that it is closely related to the number of blows made by the device per second. And the higher this number, the easier it will be for you to work with the instrument. Since not in all cases the user needs a high rotational speed, it is advisable to make his choice in favor of those devices that have a pre-installed gearbox and have an adjustable speed mode.

Electric wrenches are subdivided into impact-free and percussion wrenches according to their variety. The impact function will not be useful in all cases. Often the bolts are tight enough, so if a blow is triggered at the slightest pressure, the thread and nut will immediately become unusable. Therefore, the manufacturer provides a function to turn off shocks. Note that the rotational force of percussion instruments will always be higher than that of unstressed instruments, even if the power is equal.

Let's talk about powering the instrument. It can operate from 220V power lines, from the on-board power supply of a truck (24 V) or a car (12 V), as well as from an autonomous power supply. Most often, electric wrenches are very resource-demanding. You will not be able to work more than a quarter of an hour from one battery charge. There is no guarantee that replaceable batteries will give you at least half an hour of uninterrupted operation.And buying a third battery is too expensive.

If you do not plan to use the device for complex tasks, then purchase versions that work from the network. They do not have to be plugged into a 220V outlet. Power wrenches work great even on car power and can be transported in the trunk.

The manufacturer very rarely describes a type of percussion mechanism (only in expensive models). But this is the indicator that you should always pay attention to. Therefore, be sure to ask the seller for information about the "stuffing" of the tool. An experienced consultant will always inform you. Also, this information can be found on the manufacturer's website by reading reviews about the device.

All types of percussion mechanisms will be considered below.

• Pin clutch and rocking dog are a system with a long nose that resembles a cone. None of these systems can be used for complex tasks.

• Pin Clutch is made up of small parts. Such a system is most often found in network devices. Thanks to it, you can achieve a smooth impact, vibration damping. The mechanism has good torque. When choosing the right system, you should be careful. All insides must be durable and shockproof. Otherwise, your tool will become unusable after a couple of months of work.

• Rocking Dog has a very primitive structure. Here, the quality of the material from which the mechanism is made is not at all an indicator of reliability. Such a system is installed in budget line nutrunners. The negative side is the presence of loud noise during operation and the lack of vibration absorption function.

• The Pin Less mechanism is also of a simple design. But unlike the above-described system, this option is capable of absorbing vibration. In terms of performance comparison, Pin Less is the middle ground between Rocking Dog and Pin Clutch.

Let's consider some options.

• The most powerful cordless tool features impact wrench RYOBI R18IW3-120S... The manufacturer provides for work at 3 speeds, low speed, so as not to damage the thread or bolt. The battery comes as standard here. This battery runs on just 18 volts, but it is able to unscrew the bolts even on a tractor. Judging by customer reviews, we can say that the device has a very comfortable grip. The set includes a bag for transporting the device.

• "ZUBR ZGUA-12-LI KNU" will be ideal when working at home. It is the lightest on the market and is designed to work with furniture. The tool weighs only 1000 g but is very sturdy. The device is shock and in some cases will help out where a screwdriver of higher power failed. This small tool runs on 12 volts and a 1.5 Ah battery. With these indicators, the device will be able to work for about three hours continuously. Customers note the presence of a carrying case. On the negative side, it is noted that the battery sits down very quickly when working in the cold.

• AEG BSS 18C 12Z LI-402C. The manufacturer places great emphasis on the quality of the battery. The distinctive feature of AEG is that the same battery and charger will fit any tool from this manufacturer. The device is powerful enough, has a high rating and can work with bolts and screws of all sizes. If handled carefully, it will serve you for years. The device has one drawback - the price. In Russia, prices start at $ 300.

• "ZUBR ZGUA-18-LI K" is the best-selling product in the Russian market for impact wrenches. For $ 100, you are offered 350 N * m of torque, self-contained power supply, a carrying case and a charger.If we consider foreign models with such characteristics and configuration, then their cost starts from $ 250. And the Russian version is guaranteed for 5 years. Experts note the convenience when repairing a car. When choosing the right attachment, the tool turns into a full-fledged screwdriver. The downside is the battery. It often has weaker characteristics than what is written on the product packaging.

• INGERSOLL RAND W5350-K2 recognized as the best angle wrench. It is used in places where conventional devices simply cannot fit. The box with the device contains a charger and two 20-volt batteries. The device costs less than $ 100.

• Among the network devices, one can note BORT BSR-12... It is suitable for car repairs. The device is quite small, weighs about 1800 g, the torque is 350 N * m. The device, despite its good performance, costs less than $ 40.

• If you need to work with large trucks, disassemble large iron structures, then pay attention to the moment wrench Makita TW1000... The device operates from 1300 W and is designed for bolts in sizes 22-30. Adjustment of the tightening torque is possible. The device is made of impact-resistant plastic and comes with a carrying case and additional handle. This is the best all-round tool. But you will have to pay a lot for such characteristics: the cost in Russia starts at $ 850.

• "ZUBR ZGUE-350" - a good wrench of the Chinese assembly. It costs about $ 90. The seller gives a 5-year warranty. The device is equipped with a 5m cable.

First, decide for what purpose you want to purchase the device. Among motorists, pneumatic torque wrenches and electric rolling wrenches are widespread. For car repairs, choose a tool with a torque of 250-700 Nm and a 0.5 inch chuck. The cost ranges from $ 100-500.

For an overview of the Bosch GDS 24 Professional impact wrench, see the following video.