Comparison Dnipro-M SH-210AV vs Sturm RH2521P

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.

— 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 total weight of the tool — usually, without taking into account the installed nozzle.

In the case of demolition hammers, weight depends not only and not so much on the comfort of holding in hands, but on specialization. The specifics of the work carried out by this tool is such that a large weight is often an advantage, not a disadvantage. Therefore, modern demolition hammers are conventionally divided into three "weight categories":

— Lightweight — models weighing up to 6 – 7 kg. Designed mainly for work on vertical surfaces, when the tool has to be held on weight.

— Medium — up to 10 – 12 kg. Used primarily for horizontal surfaces.

— Heavy — up to 30 kg or more. They are used in road works, when laying the foundation and for other similar tasks where high power and productivity are required.