Cordless grinders: characteristics and tips for use

Angle grinders (abbreviated angle grinders) have long become an indispensable tool. The first samples of compact angle grinders in the Soviet Union were made in Bulgaria. The tool quickly became so popular that any angle grinder is now called a "grinder". After the appearance of sufficiently powerful and compact batteries, it became possible to make compact and convenient cordless grinders.

The most important feature of the battery-powered angle grinder is the possibility of fully autonomous operation. There is no need to run the cable from the mains socket. You can work even where there are no electrical outlets at all - in the forest, in the country, on the construction site.

The simple design of the cordless tool makes it easy to use, even at home. Despite the fact that the apartment has electrical outlets, in a hard-to-reach place, a cordless grinder is much more convenient than a power tool connected with a cord. And from the outlet during the operation of the rechargeable angle grinder, replaceable batteries are charged.

The main advantage of cordless angle grinders is portability. The battery grinder is small and light. Compared to units that are powered from an electrical outlet, rechargeable angle grinders produce much less noise during operation.

Replacement grinder batteries are often suitable for other types of cordless tools of the same brand. This allows the master to alternately work with a grinder, a cordless chain saw, and a screwdriver.

Even their low power can be considered a plus of the cordless tool. The models of electric motors used in them operate at very high speeds. This allows you to work with small diameter discs no less efficiently than large ones. The higher rotational speed also contributes to a neat, scratch-free, burr-free material handling.

The cordless tool also has disadvantages. When cutting thick, tough material is required, a low-power cordless tool may not be up to the task. Batteries "run out" pretty quickly. When processing durable materials, a single battery can last only half an hour. The battery will then need to be recharged, which can take several hours - you have to keep spare batteries close at hand.

All other things being equal, a rechargeable grinder is several times more expensive than an angle grinder of the same parameters powered by a household outlet.

Repairing cordless tools is also more expensive and more difficult. For grinders powered by 220 volts, many spare parts are compatible and interchangeable between different models. Spare parts for cordless angle grinders cannot always be found on sale.

Now the range of cordless grinders is not too extensive.The produced models differ greatly in such characteristics as: engine power, battery capacity, type of electric motor used.

The angle grinder on the battery, first of all, should be compact and convenient. The most common grinders are equipped with collector motors with two or four carbon brushes. They are available in any capacity and are relatively inexpensive.

The brushless sander is distinguished by the fact that its motor does not have a brush manifold assembly. This makes the motor maintenance-free. But cordless tools with such motors are much more expensive than machines with brushed motors.

If possible, a tool with speed control should be preferred. A portable sander with this adjustment allows the best use of discs of different diameters and different strengths.

Some materials require a reduction in tool rotation speed. For example, a metal cutting saw does not tolerate high cutting speeds. At the same time, a diamond blade for cutting extremely hard materials requires a high spindle speed.

To get a rough idea of ​​what kind of cordless grinders are, let's try to make a rough rating of some models of portable grinders of different prices - from the cheapest to the most expensive and professional ones.

Enkor hand tools are manufactured in China under the supervision of a Russian developer and customer. It is an inexpensive but high quality tool. The design of the ENKOR cordless sanders is very simple. The standard set of the AkkuMaster AKM-1825 angle grinder includes a casing, a side handle and a spindle flange nut wrench. It's good that two rechargeable batteries are included at once. But neither the batteries nor the charger have a charge indicator. The batteries take a long time to charge, which is also not very convenient.

The motor of this angle grinder is weak and overheats quickly. For grinding "difficult", viscous materials, such a grinder is not suitable. Therefore, during the development, they provided for the possibility of using discs of only small diameters - no more than 115 mm. The rest of the grinders usually allow mounting tools with a diameter of up to 125 mm.

The start button of the AKM-1825 model is rather inconvenient - it is small and tight. The battery can be rotated - this allows using the angle grinder in hard-to-reach places. But the swivel unit is connected to the motor not by wires, but by sliding contacts. This reduces the reliability of the structure.

It is interesting that the AK-1835 "extension cord" is produced for this model. Using such an adapter, you can connect the grinder to a rechargeable battery that is in your pocket or hanging on your belt. The connection is secure, and the tool itself becomes even more compact and lighter.

Having some drawbacks, the AkkuMaster grinder is much cheaper than its competitors. In addition, not every expensive instrument can boast of such compactness.

The Japanese manufacturer "Ryobi" (sometimes the name is pronounced as "Ryobi", but from the point of view of the Japanese themselves, it is the first option that is correct) is well known in Europe as a supplier of inexpensive, but very high-quality power tools.

The inexpensive model "R18AG-0" is interesting in that it can operate both from modern lithium batteries and from batteries.collected from nickel-cadmium elements. They are weaker than lithium, but much cheaper.

Japanese designers have provided everything for the convenience and safety of the angle grinder.The shape of the case is comfortable to hold and has a non-slip rubber coating. The gearbox housing not only has 3 slots for installing the front handle in different positions, but even has a heel. On this heel, you can "put" the angle grinder so that the disc will be directed upwards and will not break. The spindle lock facilitates and speeds up disc replacement.

The diameter of the tool used is limited to 115 millimeters. For a lightweight and compact angle grinder, this may even be an advantage. The consumer gets real Japanese quality at a very affordable price.

The technique of the German corporation "Bosch" is well known to the masters. The tool of this brand, which belongs to the "green" line (according to the color of the plastic housing of the unit), is designed for home use. It is not as powerful and durable as the older series (blue - "professional" color), but much cheaper.

Among the inexpensive cordless angle grinders from Bosch, which are widely popular, the PSM-10.8 Li model can be noted. Its feature is a high spindle rotation speed - up to 22 thousand revolutions per minute. This allows you to work effectively with small diameter discs.

The unit weighs less than a kilogram. The design of the handle is comfortable, the body is covered with non-slip material.

Japanese grinder "Hitachi" model G14DSL belongs to the middle class, having many features of a professional tool, but a somewhat simplified design.

The 14-volt lithium battery has a capacity of 3 ampere-hours, which ensures long-term operation without changing the battery. The grinder of this model is equipped with a very fast charger that charges the battery in less than an hour. The grinder comes with a second battery.

The tool itself is very compact and handy. The elongated body is covered with a non-slip material and completely hides the battery. Moreover, the body length is less than 30 centimeters. The spindle lock facilitates disc replacement.

The tool is fastened to the spindle with a shaped flange nut. This is not very convenient, but not too important for home use.

The Makita brand has always been considered a symbol of professional tools at affordable prices. The Japanese corporation produces both heavy and very reliable electric machines for construction work, and cheap battery units for home use.

DGA504Z is one of the simplest and most inexpensive models of cordless angle grinders from this company. The grinder is quite heavy (2.5 kg). This is due to the robust metal housing construction, powerful motor and high capacity battery. But the shape and dimensions of the body make the handling of the grinder convenient.

The electronics monitors the load of the engine and, if there is a danger of jamming, turns off the motor. The spindle lock makes tool changes quick and easy. The start button has a latch. This facilitates long-term work, allowing you not to press on the key constantly. For safe handling, the start key has a lock, which prevents the instrument from being switched on accidentally.

The affordable price of this model will attract a craftsman who wants to get a high-quality and productive tool of real Japanese quality.

This model represents the "professional" line of the German manufacturer, as evidenced by the characteristic blue color of the grinder body and the case for its storage.

The spindle speed of GWS 18-125 does not exceed 10 thousand revolutions per minute. But for discs with a diameter of 125 millimeters, high speed is not needed.

The rechargeable battery with a voltage of 18 volts is compatible with other types of Bosch hand-held power tools of the "blue" series. This allows you to use one set of batteries and one charger not only with a grinder, but also with a drill, screwdriver or hammer drill.

Smart electronics protect the engine and battery in the event of overload or overheating. The batteries of this model heat up rather quickly during operation. This does not interfere too much with work, but it is better to have a replacement kit.

The discs are attached with a shaped end washer. The cover is removed only with a wrench, and there is no anti-vibration insert in the gearbox (although there is an anti-vibration washer on the spindle itself).

These features make the grinder cheaper. Otherwise, Bosch maintains a high blue line level. The carrying case has end locks, traditional for "Bosch", which makes it possible to dock several boxes. The start key is fixed in the on position. The protection system is sensitive to tool jamming.

This is a very short sander with a heavy but compact battery. The battery is attached to the unit at an acute angle, which is very convenient when working in tight spaces.

The large handle has an anti-vibration pad. The protective cover is easily repositioned without the use of tools. Each battery is equipped with battery charge indicators. The front handle can be moved to three different positions, which is very convenient. The lockable start key facilitates long-term work with the machine.

The electronics of the grinder monitors the overload of the motor and, in case of jamming, turns it off. The motor has low power, so the protection can also work when cutting viscous materials. But the overload indicator light allows the technician to notice the danger in time and reduce the pressure on the tool. In addition, the small motor gives the spindle very high revs, which allows efficient use of small diameter discs.

The metal structure of the gearbox housing guarantees the durability of the structure and allows for long-term operation. If necessary, the spindle can be locked with a button, making it easy to change tools. The grinder of the German manufacturer is very compact, convenient and fully justifies its price.

The Japanese angle grinder of this model belongs to a professional tool. The fast charger allows you to fully charge the batteries in half an hour. The brushless motor provides high reliability and performance. An overload protection device and battery charge indicator simplify monitoring.

Despite the characteristics, DGA504 RME is much cheaper than similar grinders from other manufacturers. The price was reduced by using the simplest attachment points for the front handle and casing in the design. The disc fastening nut is also simple, shaped and requires the use of a shaped wrench to change the disc. There is no spindle brake, which makes you wait for the rotating disc to stop by itself.

But the automatic protection detects the overload of the tool and stops the motor if the disc gets stuck in the material. Air cooling ducts contain easily replaceable filters. Even with a noticeable heating of the batteries, the device remains operational.

The model is not the cheapest. But the ease of handling and reliability of the grinder makes the choice of this Japanese tool attractive.

The American concern "DeVolt" (named after the founder of the company) produces not only tools, but also accessories and workwear.Factories are located on all continents, which provides a reasonable price and a high level of service.

The cordless grinder model DCG 412 M2 is distinguished by a special shape of the handle, which has a protective clip on the front. Combined with a robust protective cover that can be easily repositioned with a simple keystroke, it provides convenience and safety when performing difficult tasks.

The spindle of the grinder has a rubber washer in the construction, which reduces the vibration of the tool. But the flange nut has a classic shape wrench fastening. The start button has no fixation; during operation it has to be held by hand. This is also done for security reasons.

To ensure safe handling, the start is interlocked. The start button can only be pressed when the safety button is sunk into the side. This is a standard feature of American power tools. Three LEDs on each battery housing show the approximate charge level. The safety device is triggered at the slightest overload and the threat of jamming the tool.

The grinder is very reliable and safe. The high price is offset by the power of the tool, high productivity and ease of use with such a grinder.

The German company "Metabo" specializes in the production of extremely reliable and productive tools for professionals. Formally, the company today belongs to the Japanese concern Hitachi. But production is still in Germany.

The WB 18 LTX BL 125 Quick angle grinder is equipped with an advanced lithium battery made using LiHD technology. These batteries can deliver very high power. The batteries have built-in overload protection, heating control and charge level indication systems.

The design of the grinder is very well thought out. The cooling ducts are equipped with air filters, which are easy to clean and replace without completely disassembling the unit. The battery attachment unit can be rotated relative to the housing at an angle of 270 degrees. The batteries themselves have a voltage of 18 volts and are fully compatible with other professional Metabo power tools.

The front handle has an anti-vibration insert. The spindle brake allows the disc to stop in just a couple of seconds. Discs are easily changed without any special tools, just by hand. The protective cover is also fixed with a convenient key and can be easily rotated into a comfortable position.

The start button is fixed in the on position. A start lock against accidental activation ensures safe handling of the grinder. The start key provides a smooth start of the motor and allows you to smoothly adjust the spindle speed during operation.

This is an expensive device, but its convenience, power and reliability fully justify the investment.

First of all, you should decide on the required engine power. The mini-grinder is small and light, it is very convenient for it to perform precise work. Such a machine will be the best for housework, when laying ceramic tiles or in a carpentry workshop. A low-power engine will not allow the use of large-diameter disks, but this angle grinder is the most inexpensive.

A weak motor is unsuitable for cutting thick metal sheets or sturdy metal pipes. Small batteries of an ultra-compact machine do not allow you to work for a long time.

Powerful angle grinders are heavier than similar ones powered from an outlet. Such a machine quickly "eats up" even the most capacious batteries. Make sure you have spare batteries included.

The engine power must be selected depending on the tasks ahead. Power from 200 to 600 watts is sufficient for most jobs.Remember that the main advantages of the cordless sander are lightness and compactness. A large angle grinder is needed if you plan to work a lot with thick metal profiles or viscous materials such as drywall.

Comparing devices of similar power, you can see that different brands have different battery voltages. The nominal capacity of the battery can also vary. The best battery will be the one with the larger total capacity. To determine this parameter, the battery capacity (in ampere-hours) must be multiplied by the battery voltage (in volts).

If possible, it is advisable to choose a grinder with a protective cover, the mechanism of which makes it easy to change the angle of its attachment. It is good if the kit includes covers of different sizes and shapes to perform different types of work.

The safety of working with angle grinders is influenced not only by the strength of the protective casing. The material from which the body of the machine is made must also be durable. The shape of the body should be comfortable to grip, and the material should not slip in your hands (especially with gloves). The shape and location of the control buttons are also very important.

If possible, you can connect the charger supplied with your grinder to a nearby outlet. It's always a good idea to have replaceable batteries: while you are using one battery, the other is being charged.

If the machine has a speed control, it is best to use the largest one possible for the specific abrasive disc. Cutting should be fed smoothly and without excessive pressure. The misalignment of the tool threatens not only that the cut will come out uneven, but also that the disc may collapse. It is very dangerous.

For coarse sanding, if a significant layer of material needs to be removed, a roughing disc should be used. In this case, the tool must be held with some inclination to the surface. Make sure that no deep grooves are left on the material to be cut. Under no circumstances should cutting discs be used for roughing. They are too thin and break at the slightest lateral bend.

If, while working with diamond discs, you notice a long sheaf of sparks, then this means that the tool is dull. You can restore its suitability by simply making several slots with such a disk in any hard material (for example, ordinary brick). A continuous ring of sparks around a conventional disc indicates complete wear of the abrasive surface. It is better to replace such a disk with a new one.

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