Comparison DeWALT D25820K vs Makita HM0870C

Power delivered by a demolition hammer directly to a drill or other working equipment. This figure is inevitably lower than the power consumption (see below) due to energy losses in the tool mechanisms.

In general, higher net power means more efficiency and productivity; the reverse side of these advantages is an increase in price, energy consumption, dimensions and weight (however, the latter is not always a drawback for rotary hammers). In addition, note that tools with similar useful power values may differ in the ratio of chiseling speed and impact power: remember, a higher frequency means less energy for each individual impact, and vice versa. So the big numbers in this paragraph can mean both high efficiency when working with hard, stubborn materials, and good performance on relatively simple tasks; these features need to be specified separately.

Also, by the ratio of useful and consumed power, one can evaluate the efficiency of the tool in terms of energy consumption: the lower the power consumption (with the same useful power), the more efficient this model is. The downside of energy efficiency is often increased cost, but it can be recouped fairly quickly in energy savings, especially if you work long hours and often.

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.

— 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.

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.

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.