Comparison Daewoo DAH 820 vs Hyundai H 850

Rated power consumed by the rotary hammer during operation. Usually, the maximum power consumption in normal operation is taken as the nominal power.

In general, the higher this indicator, the heavier and more performant the rotary hammer is, the more advanced its performance usually turns out to be. On the other hand, the electricity consumption of such tools is high. In addition, note that with the same power consumption, the actual set of individual characteristics for different tools may be different. For example, frequency and impact energy are inversely related, and for the same power input, higher frequency usually means less individual impact energy. So, according to this parameter, it is worth evaluating only the overall level of the instrument; for accurate selection for specific tasks, you need to pay attention to more specific characteristics.

Also note that power consumption data can be useful for some tasks related to catering — for example, if a construction site is powered by an autonomous generator and you need to estimate the load on this energy source.

The energy transmitted by the perforator to the material being processed upon impact; the higher this indicator, the stronger and more powerful each individual blow.

First of all, we recall that the energy of impacts is directly related to their frequency: an increase in frequency leads to a decrease in energy. Therefore, for models where the number of strokes can be adjusted, this paragraph usually gives the maximum energy achieved at the minimum speed of operation.

In general, higher impact energy improves efficiency when working with hard, stubborn materials, but requires more motor power (especially if it has to be combined with a high frequency). Therefore, it is worth choosing according to this parameter, taking into account specific tasks. So, for occasional use in everyday life, an energy of 2 J or less is enough, for home repair work of medium intensity, at least 3 J is desirable; a power of 4 J or more is already considered high; and in some industrial-grade perforators, this figure can reach 30 J.

The number of beats per minute provided by the punch. For models in which the beat frequency can be adjusted, this item indicates the entire adjustment range, for example "1600 — 3000".

High impact frequency, on the one hand, increases the productivity of the tool and can significantly reduce the time required for work. On the other hand, with the same engine power, an increase in the number of strokes per minute leads to a decrease in the energy of each stroke. Therefore, among heavy performant devices, a low frequency is often found — up to 2500 beats / min and even lower. And the ability to adjust the frequency of impacts allows you to adjust the hammer to the specific situation, depending on what is more important — productivity or the ability to cope with hard, stubborn material. For example, for old crumbling brickwork, you can set the speed higher, and for working with stone or dense concrete, it is better to reduce the frequency of impacts by directing engine power to increase the energy of each impact.

Summing up, we can say this: when choosing a perforator, you should focus on both the number of strokes and the impact energy. Detailed recommendations on this subject for specific situations can be found in special sources.

The speed of rotation of the working equipment provided by the rotary hammer. Usually, this indicates the speed at idle, without load; rated load speeds can be further specified in the characteristics (see below), but this is rare, and this parameter is still considered the main characteristic. It is also worth mentioning that in the presence of a speed controller (see "Functions"), the maximum speed value is given here.

When working in the main mode — drilling with impact — the rotation of the equipment is used mainly to remove waste from the hole, and the revolutions here are of no fundamental importance (they can be very low). Therefore, it is worth paying attention to this indicator mainly in cases where the rotary hammer is planned to be often used for conventional drilling, without impact. And here it is worth proceeding from the fact that high speeds increase productivity and contribute to accuracy when working with some materials, but reduce torque (compared to tools with the same engine power). So for heavy work with hard, stubborn materials, relatively "slow" tools are usually better suited.

Note also that drilling is not the main task of rotary hammers; therefore, their rotation speeds are noticeably lower than those of the same drills. On the other hand, in this case, low speeds are often compensated by powerful engines and high torque, which makes it possible to effectively drill holes...of a fairly large diameter, including using crowns.

The reverse allows you to switch the direction of rotation of the nozzle. It also indicates the type of switch responsible for the reverse. The options might be:

— Crawler. A switch in the form of a slider with two working positions (plus a neutral one between them, at which the tool does not turn on at all). Usually, it is able to move in the direction "back and forth" — this option is considered the most practical. The sliders are quite simple and at the same time convenient and visual.

— Flag. A switch in the form of a flag, usually installed above the start button and thrown to the right and left. One of the advantages of the checkbox is that it is right at your fingertips and can be switched almost “without unnecessary movements” (which is not always available for the slider).

— Brush (on the engine). The brush reverse differs from the two options described above not so much in the design of the switch as in the principle of operation: it changes the direction of rotation not by controlling the current on the motor windings, but by a special movable brush holder for this motor. This allows you to develop maximum power in any direction of rotation (which is not always available with electronic adjustment), and also reduces wear on individual engine components. The disadvantages of this option are complexity an...d high cost.

— Gearbox. A rather specific option: switching the direction due to the settings of the gearbox (the mechanism that transmits rotation from the engine to the cartridge). Here you can draw an analogy with turning on the reverse gear in a car: turning on the reverse affects only the cartridge with the tooling, the tool motor continues to rotate in the same direction. This allows you to use the full power of the motor in any direction of rotation; and the absence of unnecessary switches has a positive effect on the reliability of the electrical components of the tool. On the other hand, gears with a reverse function are quite complex and expensive, and therefore they are rarely found in individual professional-grade rotary hammers.

The maximum tool diameter that can be used with a rotary hammer when drilling in concrete. See "Maximum drilling diameter in wood" for details.

— Additional handle. The presence of an additional front handle on the hammer drill, usually located at the base of the chuck. This handle can be non-removable or removable, rigidly fixed or movable. Holding two handles with two hands is much more convenient than holding one and the body, as it allows for optimal distribution of the load on the hands; this is especially important during long-term work and processing of “heavy” materials.

— Depth gauge. A device that allows you to make holes of a strictly defined depth in one go, without constant measurements and without the risk of drilling deeper than necessary. Usually looks like a rod fixed to the body of the hammer drill parallel to the working tool. When used, this rod extends to such a length that when the desired depth is reached, it rests against the surface of the material being processed, preventing the drill from moving further.

— Chisel. Complete attachment for impact work with a hammer drill in the manner of chasing, leveling hard surfaces, chipping tiles, bricks, concrete, etc. Different types of chisels are produced for different tasks — flat, blade, groove, crushing peaks with a sharp tip.

— Boring bit. The presence of Boring bit in the delivery set of tool designed for processing various hard materials by drilling with impact. Buying such a s...et eliminates the need to look for a drill separately, but the characteristics of the complete attachment must be clarified before purchasing, since they may not meet the buyer's requirements.

— Charger. The presence of a charging unit in the kit allows you to charge batteries. Accordingly, for models with batteries, this accessory is necessary to power the battery. However, there are models without a charger. And hammer drills with it can differ in the model of the charger, the name of which will allow you to learn more about its characteristics and, if necessary or as needed (breakdown), buy a similar one.

— Case included. The delivery set includes a special case that facilitates storage and transportation: it provides protection from impacts and adverse conditions (moisture, frost), is equipped with a special handle for carrying, in addition, in the case, along with the hammer drill itself, a set of working tools, replacement cartridges, etc. can be placed.

— Dust collector. The hammer drill comes with a special dust collector. As the name suggests, it is designed to collect dust generated during operation, which could otherwise cause significant inconvenience. It usually looks like a bag or container attached to the body; it can be either replaceable (thrown away with the collected garbage) or permanent. The dust collector slightly increases the weight and dimensions of the hammer drill, but it can be removed if necessary.

Power cord length for mains powered drills (see above). The longer the cord, the farther from the outlet you can use the unit and the less it depends on the location of the outlets.

The weight of a fully assembled rotary hammer (in the case of battery power, with a standard battery installed). Unlike many other types of equipment, in the case of rotary hammers, light weight is far from always an advantage. So, heavy models are better suited for professional use — they are less prone to vibrations and, usually, are stronger, which is important when working with difficult-to-cut materials for a long time. But for small, simple works of short duration, a lot of weight is not required, and in this case, light models are useful, which do not require significant effort to hold on weight.