Rotary hammer: types, features of choice and application

In everyday life and in professional construction, a variety of devices and mechanisms are used. Among them, a perforator plays an important role. But before choosing and applying it, you must definitely understand all the nuances of such a machine. First of all, with what it can be used for.

When the word puncher is pronounced, people imagine all sorts of things. In the physical plane, it is a device that converts electric current into rotational motion. But builders and repairmen are interested in a completely different point: why this device is needed in practice. Any specialist will confirm that the hammer drill has great technical capabilities, while it is universal in its field of application. Inside the rock drill there is a pneumatic device that pushes the piston. This piston comes into contact with the striker, and already the striker forces the rig to reciprocate. Therefore, it comes into contact with various structures and surfaces, destroying their structure mechanically. Due to the impact, the device can punch round and other shaped holes in stone, brick and concrete walls.

The scheme of any punch, despite the design differences, invariably contains:

• electric motor;
• percussion apparatus;
• reducer;
• chuck for holding drills and securing nozzles.

But these components are not always satisfied. A large number of manufacturers equip their equipment with:

• vibration blocking devices;
• systems that fix the position of the working part or the depth of processing;
• devices that remove the generated dust.

Note that all this is optional and largely remains at the discretion of the developers. Even changing the power of impact or drilling is not always possible. However, sophisticated manufacturers do not ignore these kinds of moments in their efforts to grab the attention of buyers. An important characteristic of the device is the vertical or horizontal installation of the electric drive. In any case, 100% of the motors with which the perforators are equipped are made according to the collector circuit.

Most of the serious rock drills designed for use by professional builders are equipped with vertical motors. When the drive is placed horizontally, it works more efficiently in difficult-to-access or narrow areas. However, the mechanical load on the power units is slightly higher, and the cooling of the electric drive becomes more difficult.

Skilled technicians are more likely to choose vertical drills. They are considered more comfortable for long periods of work. Also, the difference is that this arrangement of the electric motor makes it possible to replace the rolling bearing with a mechanism with a crank and connecting rods. In addition to the engine, it is worth paying attention to the main working unit of the hammer drill. Designers are constantly striving to provide the best balance between electrical power consumption and the force of impact.

To solve this problem, an electro-pneumatic working unit is better suited than an electromechanical one (which is why the second type is much less common in modern models). If you open the percussion apparatus installed in a lightweight puncher, you will find:

• piston;
• friction bearing;
• ram;
• firing pin.

When the motor is started, the rotary motion from the motor is transmitted to the inside of the bearing. And that clip, which is located outside, makes an oscillatory movement (it is tightly coupled to the piston). The gap separating the piston from the ram is filled with air. During operation, it undergoes alternating contraction and increase in pressure. Following these differences, the ramming unit reproduces the piston stroke by striking the striker. And the striker is already driving the chisel hiding in the chuck. The pneumatic device can shut off by itself if the rock drill is idling. As soon as the ram moves forward without encountering a solid medium in the way, it opens a hole in the piston chamber.

Medium and heavy rock drills, thanks to the crank system, can deliver very strong blows, their energy reaches 20 kJ. But the basic principle of operation differs little from that already described. The difference is that the transfer of energy from the motor occurs to the gear. The force is transmitted through the worm-type shaft. The final link on the shaft turns out to be a crank, which already transmits an impulse to the working mechanism.

It should be noted that high power rock drills are usually equipped with an active anti-vibration system. Technically, it is quite simple: it is a counterweight with a spring that takes up the resulting vibration. Of course, it is not capable of absorbing 100% of vibrational vibrations, but their significant reduction greatly helps the craftsmen. The well thought-out design of the rotary hammer handle helps to further reduce vibration. It is specially secured only by means of a hinge with a spring. But in most models, a passive vibration suppression system is also provided. This is the name of the special rubber pads. Their additional function is to prevent hand slipping.

During operation, the regulation of the rate of rotation of the electric motor is of great importance. Typically, this pace adjusts to the strength of the pressure on the start button. But some models of rotary hammers are equipped with a special regulator. Electrical circuits can also be different. The simplest option is indistinguishable from a household drill. As you might guess, a large amount of heat is generated during the operation of the electric motor, as well as the impact mechanism. To remove and remove it, air is captured by the fan wheel. Such a solution, as practice shows, almost eliminates overheating during long work. To further reduce the risk of burns, some of the rotary hammer drills are fitted with plastic pads. But nevertheless, experts recommend taking breaks from time to time - this will help keep the device working longer.

It is dangerous to damage the device itself or cause injury. To avoid such a development of events, special protective couplings help. They also save the electric motor from overloads. Thanks to the clutch, if the drill stops, the engine armature continues to move. At the same time, the hammer drill chuck is disconnected from the shaft, and therefore does not burn out. Friction clutches are formed by special disc assemblies, initially pressed against each other. As soon as the chuck stops, the relative position of the discs changes. There is also a spring-cam version of the clutch, in which the halves of the device are pressed by a spring. When blocking the main part of the tool, the half-couplings slip. At this moment, a slight crackling sound is heard (it is emitted by the teeth).Such a system is more reliable, but sometimes it allows false positives.

When describing the work of rock drills, gearboxes cannot be ignored either. The role of these components, along with transferring rotation to the chuck, is to support the action of the percussion mechanism. Each gearbox installed on drilling machines has a constant gear ratio. To set the number of revolutions of the cartridge per minute, a special regulator is used. Gears are lubricated only during the manufacture of the device and during its repair (and this work should be done by professionals).

Further - a cartridge of one of three types (other options have long ceased to be used):

• cam;
• quick-release;
• SDS format.

It is the SDS system that almost completely dominates today - less than 10% of drilling machines are equipped with parts of other types. The advantage is obvious: when the chuck is screwed on, it only needs to be turned to secure it. Rotary hammer bodies are usually assembled in two parts. To connect them, in addition to screws, side mounts can be used.

For household work, perforators weighing no more than 4 kg are used. Intermediate (semi-professional) devices have a mass of 5 to 8 kg. Only rotary hammers from 8 to 10 kg fall into the category of professional systems. In most cases, buying a semi-professional device is sufficient. It is capable of punching an opening not only in a concrete wall, but also in a steel grating. More serious equipment is needed, mainly, for teams performing large repair and construction work. Such mechanisms can operate continuously for a long time, however, purchasing them for home use is unnecessarily expensive.

There are other classifications of drilling machines. So, they are sometimes divided according to how the effort is generated. The pneumatic rock drill contains:

• mobile pistons working in turn;
• strikers receiving impulse from pistons;
• air cushions to help build up pressure.

The peculiarity of such a system is that it works without pressing hard. It is simply not required for the normal functioning of the mechanism. Moreover, too active pressure leads to frequent breakdowns of equipment. In the household and semi-professional class, there are devices with an electromechanical percussion part. It works like this:

• under the influence of the eccentric, the spring is activated;
• connected to the lever;
• the lever sets the percussion mechanism in motion;
• the impulse from the latter is transmitted to the rig.

The approach to working with such a hammer drill is different from the one described above. Not only is it possible to press, it also helps to strike more effectively. By geometry, drilling machines are usually divided into L-shaped and horizontal. The former are considered preferable where the length of the apparatus and the effective cooling area of ​​the motor are important. But in general, they turn out to be cumbersome and not maneuverable enough.

The most compact units are equipped with an SDS + shank. Its diameter is 1 cm. This technique can punch holes no larger than 3 cm. Despite its limited capabilities, it is popular, since the cost is less than that of rotary hammers with other methods of fixing the rig. Professionals definitely prefer the SDS-max system. With its help, it is possible to punch holes up to 5.2 cm. However, such possibilities are realized only when the drill is fixed as securely as possible. In almost every device that is heavier than 8 kg, it is the SDS-max mount that is used. For rock drills equipped with the SDS-top clamping system, the shank diameter is smaller than in the previous case.

Such drilling machines can punch holes with a cross section of 1.6-2.5 cm. The hammer drills produced now can have two or three modes. The third mode is striking. Important: Hammerless drilling is a minor function for these machines. If you need it, it is better to purchase a simple drill. For clean drilling, conventional drills are used. An electric rock drill, which draws power from the mains, must have a long power cord. It is these devices that are used in domestic conditions. But in remote areas, where the power supply is unstable or completely impossible, wireless machines are used predominantly. They receive electricity from a battery.

Vertical (aka barrel) perforators are not only heavier and larger than their horizontal counterparts. The difficulty is that such a device requires continuous lubrication of the engine. But if necessary, drill down - it is they who are out of competition. When you need to punch a hole in the floor and ceiling, lay a pipe for water and gas - a vertical puncher is ideal. It is important to understand that such devices often do not have a drilling mode. When buying, it is imperative to clarify what functions they can perform. But, in addition to the pneumatic, (in some cases), the hydraulic type of perforators is also used. Attention to these is due to the fact that the pneumatic actuator has reached its limit of efficiency.

Attempts to make it even more powerful turn into an unjustified increase in the size of the apparatus, making them heavier. But even at this price, it is not possible to maintain the durability of the drilling devices. As practice shows, a hydraulic rock drill can drill 2-3 times more powerful and 2 times more productive than an outwardly identical pneumatic device. The reason is simple: voltage pulses in the liquid are transmitted more efficiently, the tool will be more durable in operation. The question may arise about chippers, because jackhammers, using the power of compressed air, work quite effectively. However, there is a significant difference between them, which precludes direct comparison.

Their functionality is limited. The hammer drill is much more versatile, it can replace the drill at the same time. But if you plan to carry out exclusively percussion work, the jackhammer will be more practical. All manufacturers indicate that the punching machine can be in impact mode for a maximum of ¼ of the total operating time. Those who violate this rule quickly find that the resource of the tool is exhausted, it cannot be restored. It must be remembered that a jackhammer is larger and heavier than a hammer drill. In domestic conditions, it is used quite rarely. Working with this tool requires not only skill, but also considerable physical strength. The equipment for the two devices is approximately the same.

Sometimes you can hear the question about which perforator should be used for socket outlets and other "delicate" works. It is quite possible to execute them with the simplest devices. Some amateur builders generally use hammer drills for this purpose. But the drilling machine must be at least 750 watts. If this power is not achieved, there is no point in buying a tool.

A very important point: the use of large and small rotary hammers. Their preferred size is determined by what the technique will be used for. In domestic conditions, it is recommended to limit yourself to a tool with a length of 36.8 and a height of 21 cm.Attention should be paid to the size of the drill. Its length (including the tail) varies from 10 to 100 cm.

But whatever the size of the hammer drill, whatever the shape of the device, the right choice of accessories is of great importance. It depends on them whether it will be possible to do the necessary work or not. Most often, a drill is used when working. The difference between individual drill designs has to do with which liner is used. There are 4 types of shanks in total:

• SDS +;
• SDS max;
• SDS quick;
• SDS top.

SDS + format constructs are the most popular and widespread. Their standard sizes are 1 cm in diameter and 4 cm in length. You can use such shanks on drills with an outer cross section of 0.4 to 2.6 cm. These devices are easy to distinguish even externally: they have 4 open grooves that allow you to fix the part in the chuck. Tip from 2.6 to 4 cm can be combined with SDS max shank. The section of the section inserted into the chuck is 1.8 cm. The length of the tail part of the drill reaches 9 cm. But SDS quick shanks can be found only among the products of the Bosch concern. Thanks to the additional parts (keys and holder), they allow the use of drills and screwdriver bits. The rarest version is SDS top, the part that is fixed in the chuck is 7 cm with a diameter of 1.4 cm.

Operational safety and the speed of drilling and drilling depend on which alloy is chosen. With the help of a screw auger (with almost flat grooves), usually not too deep holes are made. Regardless of their exact depth, complete dust removal is supported. As a result, the load on the tool is reduced, and its overall resource is extended.

But using a drill with steeply inclined grooves, you can drill several deep holes in a short time. However, the wear of all parts increases significantly. You cannot do without grooves - they provide accurate centering during drilling. If perfectly smooth borax were used, they would create a strong vibration. The longer the drilling element, the more difficult it is to work with it and the more relevant safety precautions are.

The tips used on drills are of three types:

• wavy;
• cruciform;
• with special soldering.

There are two tip materials: diamond-plated and made from Pobedit. Diamond tools are very good where you have to punch through high-strength natural stone or reinforced concrete. In such conditions, the drill will not break and will last a long time. As for the drinks from the victors, they can have different strengths. The softest ones can confidently cope only with bricks and second-class concrete.

Products of medium strength group are suitable for most household jobs. Finally, the most durable victorious soldering approaches the quality of diamond plating. Important: the more expensive the drill, the higher its practical capabilities. There is simply no chance of buying a very powerful part at the lowest price.

It is not difficult to distinguish a drill from a drill:

• unequal shank (smooth and geometrically intricate, respectively);
• differences in the function of the spiral ribs (for drills, they must pierce the material, for drills, only remove the resulting dust aside);
• increased mechanical strength;
• suitable exclusively for hammer drills (while the set of drills can also be used when working with a drill).

An accessory such as a crown deserves a separate discussion. It is thanks to such a nozzle that perforators can be used for electrical work. They are easy to punch holes for junction boxes, switches, sockets and socket outlets. A typical crown always includes a shank to which the cylinder is secured. And already this cylinder is equipped with teeth from Pobedit or a diamond film is sprayed on it.

The high cost of a diamond core bit is fully justified, because it is capable of penetrating high-grade concrete and even reinforced concrete. The diameter of such products ranges from 2.5 to 13 cm. They are mainly needed by professional builders. The diameter of the victorious crowns varies from 3.5 to 12 cm. However, regardless of the size, they will break when working on a hardened wall.

If an impact crown is used, it will help:

• punch through hard material;
• overcome an unstable wall;
• pass a lightweight or conventional overlap.

The same work can be performed with non-impact bits, but it is better if they are equipped with a diamond layer. In order to guarantee a long service life of the crown attachment, it is imperative that the instructions are followed. If a drill is placed in the center of the nozzle, then it allows you to drill materials strictly according to the marking. Important: the shank should be matched to the hammer drill.

Working with a hammer drill, concrete is very often hammered. Such work involves the use of a chisel. Since the tip of this bit is not hardened, it will have to be sharpened systematically. With the help of a chisel, remove the tile or knock down a layer of plaster. There is another type - the so-called channel chisel - which is needed for driving recesses for electrical cables. The working edge of the chisels can vary in width. Most of the structures in practice have a 2 cm wide edge. The maximum length is 25 cm.

But the drilling of holes in brick and concrete walls is done with a lance. In skilled hands, this attachment is able to prepare a strobe for electrical wires of various cross-sections. But the disadvantage of even the best picks is the lack of accuracy in work. And it does not depend on the skill of those who hold the instrument in their hands, on their diligence and thoroughness of marking. To grind the floor, wall or ceiling for pulling the same wires, use semicircular blades. Such a device allows you to replace more expensive tools - wall chasers. When choosing a nozzle, they pay attention to its length and diameter, since the efficiency of the work depends on these parameters.

Unlike attachments, they are hidden inside, because they are used only for normal operation of the electric motor. The problem is that the brushes wear out pretty quickly. Coal dust also damages them. Both factors disrupt the functioning of the electric motor. If you use graphite brushes, they will last a very long time. However, the high rigidity interferes with the exact fit of the part. As a result, the collector will quickly fail. The properties of carbon brushes differ exactly the opposite. The optimal way out is to use brushes of a mixed composition.

Choosing rotary hammers, you need to focus not only on their size, power, engine type, and so on. It is of great importance which company made the tool. One of the more budgetary options is Zubr model ZP-26-750-EK... This Chinese design has excellent impact properties. Despite the cost-effectiveness of the device, the perforator is made in a vertical pattern, which allows it to deliver powerful blows. It is noted that the tool is capable of hammering holes with a diameter of 2.6 cm even in high-quality concrete. Among other positive features, consumers call a competent ergonomic concept. However, it must be borne in mind that the mains cable is short - 150 cm, and there is also no reverse function.

The ratings of rotary hammers invariably include the products of a Japanese company. Makita... In the 2018 season, she introduced model HR2440... Experts point out that this modification has a good balance of mass and power. The tool is easy to hold with one hand. Despite this, it is possible to punch holes with a diameter of up to 2.4 cm. Such properties make it possible to consider a fairly high price quite justified. The only limitation to keep in mind is that there is no chiseling option.

It is impossible not to mention the Russian-made products in the review. An example of this is the model Interskol P-22 / 620ER.

Builders and repairmen noticed that such a hammer drill at the same time:

• highly productive;
• unpretentious;
• repaired without problems;
• is relatively inexpensive.

Despite the limited power (620 W), as well as the absence of a purely shock mode, the product allows you to make holes in brickwork and not too thick concrete. The lightness of the design makes it comfortable for one-handed operation. You can carry the instrument from place to place and store it in a case. The designers have provided for a reverse. However, sometimes there are complaints of an unrecoverable unpleasant odor.

For work at height, according to some experts, it is best suited model AEG KH 24 E... The product is relatively light (2.4 kg), which allows you to safely use it for insulation and finishing works on facades and cornices. It is important that the hammer drill can drill holes up to 2.4 cm. Its developers have provided a mode for tightening screws. The tool heats up relatively little, cools down in a short time, but there are no drills and lubricants in the kit.

If the impact force is critical, you must choose model DeWALT D25124K... The product of the American industry strikes 3.4 J. The developers were able to ensure proper suppression of recoil energy and vibration vibrations. The hammer drill is suitable for electrical work and other manipulations, accompanied by the laying of strobes. Since the scope of delivery includes a keyless chuck, it is possible to replace a conventional drill with the DeWALT D25124K.

On a general level, functionality stands out Bosch GBH 2-26 DFR... It is her many connoisseurs who recommend buying for work at home and at a semi-professional level. The design confidently drills and hollows a variety of surfaces, changing the chuck is quick and easy. Wear is extremely low, even with very intensive use.

Separately, it is worth talking about cordless rotary hammers. Important: among them, it makes sense to choose only models with the latest generation of lithium-ion batteries. If price is critical, it is helpful to opt for Interskol PA-10 / 14.4R-2... Although the tool, judging by the reviews, is reliable, its motor is frankly weak. Due to the impact energy of only 0.9 J, there is no point in using this attachment to handle hard materials.

In a concrete wall (unless it was additionally reinforced), a perforator will pierce a hole with a diameter of up to 1.6 cm.Therefore, it will be possible to easily stretch wires from one room to another. In part, weakness is compensated by lightness and small size. The manufacturer claims that this model can work in the mode of a conventional drill and even replace the screwdriver. However, she does not know how to hammer walls, and also does not dampen vibration during operation.

An excellent alternative is Bosch GBH 180-Li... German engineers have managed to create high quality batteries. Therefore, the number of sudden stops and interruptions in work is minimized. Charging the battery from scratch takes only 40 minutes. It is also important that the package includes 2 batteries, so you can not interrupt at all, if necessary. The developers also made sure that the tool was comfortable and pleasant to hold. Its spontaneous activation is excluded. The replacement of the brushes is carried out without disassembling the body. The hammer drill is assembled flawlessly. It can be used to make holes up to 2 cm in diameter.

This category includes only models that put 12 J or more in each blow. This allows you to split even sturdy stone walls with ease. It is worth considering in advance that any instrument of this level is quite heavy. Its functionality is limited to hammer drilling and chiselling; a professional rotary hammer is not suitable for replacing a drill.

DeWALT D25601K - American development manufactured at a Czech plant. This model hardly fits into the category of professional, striking just 12 J exactly.It can be used when processing natural stone and concrete without hardening. Consumers note that it is very convenient to use such a tool, it dampens vibrations well. Therefore, it is recommended for moderately difficult repair work.

The exact opposite is the German model Metabo KHE... It is capable of developing a strong impact (up to 27 J) and can drill into processed structures. The flip side of this perfection is a significant weight (almost 12 kg). Layout can be difficult. And the cost of the product is very high. To make it clearer, let's consider a few more models, describing their capabilities. Perforator Hammer PRT 650 A will be able to help when you need to hang a chandelier or other ceiling lamp, fix the cornice. With its help, tiles are also beaten off, baseboards are attached. In principle, you can use this device to move electrical outlets, as well as to alter the electrical network. However, the resource of the device is quickly consumed with serious strobing.

DeFort DRH-800N-K, judging by the reviews, it is distinguished by increased power. This model is great for renovating an apartment. The delivery set includes 3 drills of different sizes, a lance and a chisel. The turnover control is carried out using a reliable electronic board. The hammer drill is capable of working in reverse mode - starting in this mode helps to immediately unscrew the stuck drills. BORT BHD-900 executed in a horizontal pattern. The developers promise that it will be possible to carry out finishing work with minimal costs. The device, like the previous device, is capable of working in reverse mode. The tool can simply drill, puncture and chisel. Important: it is incompatible with any kind of crowns.

And yet they choose not so much the brand and model as a specific device. The loudest name can deceive, and the reputation of the manufacturer does not always save. Reviews are what consumers should be interested in first of all. But in order to correctly understand what is said in them, one should take into account the meaning of each technical characteristic. When choosing a hammer drill for a home, the decisive criteria will be the power and force of the blows (these values ​​cannot coincide due to the law of conservation of energy).

At home, in the country and in the garage, models with a keyless chuck are recommended. If necessary, you can change it as quickly as possible. But a powerful construction hammer drill is often equipped with an ordinary cartridge. It is also useful to pay attention to the diameter of the holes that need to be made.

Optimal home models are moderately powerful, relatively lightweight, and inexpensive. That is, these are not the cheapest, but also not extremely expensive devices. Lovers of high quality should give preference to the products of Japanese and German firms. Regardless of the country of production, it is worth considering the frequency with which the strikes are delivered. By increasing it, they pierce the same hole in less time (and vice versa).

You also need to look at what modes the device is capable of operating in. If there is only one mode, then the hammer drill is, in fact, an improved drill. These tools are suitable for drilling in wood and metal. When it is not clear in advance what kind of work is to be carried out, it is recommended to choose a tool with three working modes. True, such a device is more expensive than a relatively simple option. Whatever the reviews, you need to take a critical look at the puncher. It is useful to hold it in your hand. And not just "weigh", but try it in action. The removable side handles are very nice. They allow you to hold the drilling machine with confidence, and after removing it, you can work calmly in a tight space.

The dust protection function will be useful.It is unlikely that work will be done in a sterile environment and that particles of material will not hang in the air. For continuous operation, vibration protection is useful. Moreover, it not only provides comfort, but also protects health. When choosing these and any other additional options, you need to dwell only on those that are really needed - then there will be no overpayment. It is useful to pay attention to the complete set of the perforator. The more items it contains, the quieter the work will be. Ideally, when in a case or box there are replaceable brushes for an electric motor, drills, an adapter cartridge. Of the professional models, the best is the products under the brands Bosch, Makita. And for domestic use, products of other brands made in Russia are also suitable.

A home appliance that meets the basic expectations of users has the following parameters:

• total power 0.5 - 0.9 kW;
• impact force - 1.2 - 2.2 J;
• 3 basic operating modes;
• clutch for protection;
• the ability to change the speed of the shaft;
• mounting system SDS +.

Even relatively inexpensive rotary hammers still take substantial funds out of your pocket. And it is very important to use them so that the costs are not wasted. Experts advise using only drills, cartridges, other consumables and spare parts (even lubricants) from the manufacturer. All maintenance work must be carried out regularly. The exact frequency of it is spelled out in the instructions.

Even if the instruction permits long-term continuous operation, it is advisable to interrupt periodically and let the device cool down. Deep holes, especially in strong materials, are drilled in several passes. It is necessary to hammer walls and floors in sessions of 2 minutes with a break for rotation. In case of minor problems, it is better to immediately contact a certified service center. It is necessary to drill porous loose substances only in a non-shock mode, hard surfaces are processed only under the condition of liquid cooling.

The utmost care must be taken when working with concrete structures and their parts. You can almost always come across reinforcing elements. Getting into them with a drill or drill will be safe only if there is a protective sleeve on the device. If not, all possible measures must be taken to prevent the drill from blocking in the channel. The hammer drill, of course, is always held with both hands, and you only need to stand on a stable surface.

Clothes are chosen so that they do not cling to the drill. Before starting work, make sure that the drill does not get into the electrical wire. If there is no scheme, you need to examine all surfaces with a detector and plot the result on the plan or make a markup. It is necessary to clean, wash and dry the punch immediately after finishing work.

Useful information on choosing and using a punch is waiting for you in the video below.