Comparison Zubr Professional ZM-40-1700K vs Bosch GSH 11 E Professional

The power of the engine used in an electric or gasoline demolition hammer. This parameter is used to indicate the total power consumption (useful power is less due to losses in the mechanisms) and, accordingly, it determines the connection requirements: the power grid must be able to deliver the required current without overloads and failures.

In general, the more powerful the tool, the better it is able to handle hard materials or large volumes of work. High power values make it possible to provide adequate energy for each individual impact and/or numerous strokes per minute. At the same time, we can say that power is a secondary parameter, and when choosing, you should look primarily at more practically significant characteristics — the same impact energy or impact frequency.

The greatest kinetic energy that a demolition hammer is capable of delivering on each individual blow.

The higher the impact energy, the stronger each blow is and the easier it is for the demolition hammer to “bite” into complex hard materials. On the other hand, there is not always a real need for high values, despite the fact that this parameter significantly affects the total cost of the tool. Therefore, it is worth choosing a demolition hammer according to the impact energy, taking into account the specifics of the materials for which it is planned to be used. Detailed recommendations for specific cases can be found in special sources.

It is worth noting that since recently, many manufacturers (primarily well-known ones) have been testing impact energy according to the new EPTA standard, which on the same tool gives lower energy values than the old standards. Therefore, when choosing, as well as when directly comparing different models (especially those with similar characteristics), it's ok to clarify by which standard the power was measured.

The maximum number of blows that a demolition hammer can deliver in a minute.

The higher this indicator (with the same impact energy, see above) — the more performant the tool, the better it is suitable for large volumes of work. In addition, the high frequency of operation is also able to compensate to a certain extent for the low impact energy: the pike can overcome a small amount of material in one blow, but if there are many such blows, the difference from a more advanced demolition hammer may not be so noticeable.

For different types of work, the optimal number of strokes will also be different; specific recommendations can be clarified by special sources.

— SDS+. SDS is an abbreviation for the German “Steck-Dreh-Sitzt”, “insert-turn-fix” (there is also an abbreviation for Special Direct System). This abbreviation unites several types of tool chucks and shanks for them, used in modern tools (including jackhammers). A common feature of all types of SDS is that the working attachment can be changed without using an additional tool. Specifically, SDS+ is designed for a 10 mm size shank with 4 slots, which is inserted into a 40 mm chuck during installation; attachments with a size of 4 to 26 mm and a length of 110 to 1000 mm are made for such a chuck. These are very small sizes by the standards of jackhammers; therefore, SDS+ is found exclusively in low-power tools, and even then quite rarely.

— SDS Max. A modification of the SDS+ chuck(see above), distinguished by its larger dimensions — designed for a shank with a size of 18 mm with 5 slots, inserted by 90 mm. This variety was originally designed for large attachments with a size of 20 mm, and the maximum size of the tool is about 55 mm. This makes it possible to use such a chuck in a medium and even heavy-duty tool (see "Weight").

— SDS Hex. A specific type of SDS chuck, designed, as the name suggests, for hexagonal shanks (hex stands for “hexagonal”). In addition to the shape, SDS Hex differs from the standards described above in two ways: firstly, such...a chuck is used exclusively for impact attachments of chipping hammers, and secondly, it is available in several size options (see below), while SDS+ and SDS Max are also used for drills and have a fixed size.

— Round. A type of chuck used mainly in light and medium weight tools (although there are exceptions). It is somewhat inferior to SDS chucks in terms of practicality and reliability, but it is also cheaper.

— TE-S. A proprietary chuck type used in chipping hammers from Hilti; not used by other manufacturers. Shanks of this type have a hexagonal shape with 6 grooves.

The nominal size of the SDS Hex chuck (see Chuck Type) installed in the demolition hammer.

The larger the cartridge, the heavier the tool, usually, and the more complex and voluminous the work for which it was created. The minimum SDS Hex size in modern demolition hammers is 10mm, the same as SDS+; accordingly, similar mounts are found in light class models (see "Weight"). And in heavy professional units, the cartridge size can exceed 30 mm.

— Soft start. The presence of a soft start system in the design of an electric demolition hammer (see "Type"). The features of the electric motors used in modern power tools are such that when turned on directly, the rotation speed increases very sharply; this leads to rather strong jerks, increasing the risk of letting go of the tool. In addition, starting currents are high, which increases the load on the power grid. To avoid these phenomena, soft start systems are installed: they limit the starting current, allowing you to avoid sudden surges and power surges in the network.

— Adjustment of the number of strokes. The presence of a regulator that allows you to change the number of blows (see above) issued by a demolition hammer. This function makes it possible to adjust the mode of operation of the tool depending on the specifics of the situation: for large-scale work, you can bring the number of strokes to the maximum and provide the necessary performance, and for small volumes that require accuracy, reduce the frequency so as not to “gouge too much”.

— Maintaining the number of strokes. The presence of a system that automatically regulates the number of blows (see above) issued by a demolition hammer. This system adjusts the operating mode of the tool in such a way that the frequency of impacts remains the same regardless of the load on the working noz...zle. This has a positive effect on the quality of work, and also increases the service life of the demolition hammer and replaceable nozzles.

— Power button lock. This term, usually, means the ability to block the power button of the demolition hammer in the on state — so as not to strain your finger, constantly holding it during operation. This is especially useful during long jobs where holding down the button all the time would be quite tiring. In addition, a lock in the off state can also be provided — this function plays the role of protecting against children, because. the blocking is done in such a way that only an adult can turn it off.

— Vibration protection system. This term implies various devices and design features — dampers, counterweights, shock-absorbing materials, etc. — reducing the vibration of the tool felt by the operator. Powerful vibrations have a negative impact not only on the accuracy of work, but also on the well-being of the user: with a short exposure they lead to rapid fatigue, with a long exposure they can be harmful to health. To avoid this, various protection systems are provided. At the same time, we note that this function is really necessary only for long-term regular work, so it cannot be called mandatory for modern demolition hammers. In addition, the types of vibration protection and, accordingly, its effectiveness in different models can vary markedly.

— Carbon brush replacement indicator. The presence in the design of an electric demolition hammer (see "Type") of an indicator signaling the need to replace the carbon brushes of the engine. Such brushes are one of the most important parts of the collector electric motor: they provide the transfer of electricity from the stationary part of the motor (stator) to the rotating part (rotor). However, upon contact with the carbon brushes, the moving rotor gradually erases them, worsening the contact and reducing the efficiency of the electric motor (up to complete failure); and the inevitable vibration during operation further accelerates this process. In order to keep the engine running, the brushes must be changed periodically. This indicator warns the user about the need for such a replacement; monitoring the condition of the brushes in this way is easier than keeping track of hours of operation, assessing the condition of the tool “by ear”, or using other impromptu methods.

— Additional handle. The presence in the design or delivery set of an additional handle — in addition to the main one. This feature makes it easier to hold the tool with two hands; theoretically, the second hand could hold on to the body directly, but in fact it is inconvenient, and often unsafe. Almost all modern demolition hammers involve a two-handed grip during operation, so this feature is found in the vast majority of tools. The only exceptions are certain models of the light class (see "Weight"), in which there is nowhere to put an additional handle — it is easier to provide a case that is comfortable to hold.

— Pika (chisel). Availability of a working nozzle in a set of delivery of a demolition hammer. The purchase of such a kit can save the user from the need to buy a nozzle separately — in other words, by purchasing a hammer with a pike, you will immediately receive a tool ready for work. However, it must be borne in mind that there are many types of nozzles, with their own specialization, and it is not a fact that the complete version is suitable for the types of work for which it is planned to use the tool. Therefore, it's ok to clarify the features of the complete nozzle separately. Note that the common name "peak" is technically more correct. Nozzles are often combined under the term “chisel”, however, a pick-chisel is just one of the varieties of peaks that has a flat, pointed blade a...nd is designed to cut through metal parts and punch through hard surfaces. In addition to it, there are also pick-scrap (for crushing and loosening), pick-blade (for processing flat surfaces), pick-rammer (for compacting soft materials such as soil or putty), etc.

— Case. The presence in the delivery set of a hard suitcase — a case — designed for storage and transportation of a demolition hammer. Of course, other devices can be used for these purposes — bags, boxes, etc. — however, complete cases are perhaps the most convenient option. So, they are quite comfortable to carry in your hands, the hard case protects the contents of the case and surrounding objects well from each other, and the tool and accessories for it most often fit tightly into separate recesses and do not hang around the suitcase. Note that in the absence of a case in the kit, the possibility of its separate purchase, usually, is not provided.

The length of the power cord provided in the design of the electrically powered demolition hammer (see "Type").

A long cord, on the one hand, allows you to work away from sockets and eliminates the need to once again switch the tool from one outlet to another; on the other hand, it tends to get confused and create inconvenience, besides, insufficient length can be compensated for by using an extension cord. Therefore, in modern demolition hammers, the mains cable is rarely longer than 5 m, and when choosing this parameter, you should proceed from how important freedom of movement and the ability to work without extension cords are for you.

The noise level produced by a demolition hammer during operation. The lower the noise, the more comfortable the instrument will be to use. However, it must be said that this parameter is quite approximate: the actual noise level depends on the specific mode of operation, the nozzle used, the material being processed, etc. Nevertheless, the indicators claimed in the characteristics make it quite possible to evaluate the overall “loudness” of the instrument – for example, in order to choose the appropriate noise protection means.

When evaluating the noise level, you need to keep in mind that the decibel is a non-linear quantity. Therefore, it is easiest to use comparative tables for evaluation. Here is a simplified version of a similar table for the noise range covered by modern demolition hammers:

75 dB — loud scream at a distance of 1 m;
80 dB — ringing of a mechanical alarm clock at a distance of 1 m;
85 dB — motorcycle engine with muffler in close proximity;
90 dB — freight car at a distance of 7 – 10 m;
95 dB — noise in the subway car on the stage;
100 dB — industrial shop;
105 dB — mid-range home theater at full volume.