Comparison Zipper ZI-ELB380 vs Zipper ZI-ELB70

The type of chuck used in the power drill (see "Type"). Different types of cartridges differ mainly in the way they open / close:

— Key. Drill chuck with classic round shank, opened and closed with a special key. Such a chuck is considered somewhat more reliable than a keyless chuck and is better suited for working with hard materials at high torques. On the other hand, replacing the drill in it is not so convenient, and if the key is lost, it is generally impossible.

— Quick release. A chuck that can be opened and closed manually without the use of keys. Just like the key, it is designed for round shanks. The main advantage of keyless chucks is obvious: it is more convenient and faster to change drills in them, moreover, this possibility does not depend on the presence of a key. The disadvantage of this option is a slightly lower reliability of holding the drill; however, this is often not critical even in the case of power drills, originally designed for heavy work.

The type of internal combustion engine used in a power drill.

— 2-stroke. The main advantages of two-stroke engines, in comparison with four-stroke ones, are simplicity of design, low cost, as well as higher power per unit volume (as a result, smaller dimensions and weight). Among the shortcomings, it is worth noting a higher fuel consumption and noise level, as well as the need to prepare a gasoline-oil mixture for refueling. However, these shortcomings in this case cannot be called critical, due to which two-stroke engines are used in most modern motor-drills of all price categories.

— 4-stroke. Four-stroke engines are less noisy and more economical than two-stroke ones, and they need to be filled with gasoline and oil separately, which is much more convenient to use a mixture. On the other hand, they are more complex, heavier and more expensive, and therefore are rarely used, mainly in fairly advanced motor drills (although not necessarily high-power ones).

The working volume of the motor-drill engine.

A larger volume (with the same type of internal combustion engine, see above), on the one hand, increases power, on the other hand, increases fuel consumption. However, in general, this parameter is a reference, and when choosing it is worth paying attention to more practically significant indicators — power, speed, gear ratio, etc.

Engine power of the motor drill in horsepower. Horsepower is traditionally used to denote the power of internal combustion engines. 1 HP approximately equal to 735 watts.

Power is one of the key parameters for any motor auger: the higher it is, the higher torque can be achieved on the drive shaft, the thicker augers can be used with the unit and the better it is suitable for complex work and “heavy” soils. On the other hand, high power significantly affects the price, dimensions and weight of the engine. Therefore, manufacturers choose this parameter based on the price category and general purpose of the tool.

The most modest engines, about 0.8 – 1.5 hp, are installed in power drills (see "Type") — for such devices, high power is not needed, but light weight and compactness, on the contrary, are critical. For motor drills, indicators are 1.6 – 3 hp. correspond to the entry level, 3 – 5 hp. — medium, and in the most powerful models, motors of 7 – 8 hp are installed, which makes it possible to work with screws with a diameter of half a metre or more. At the same time, note that units of the same power may differ in screw diameter and other performance characteristics.

Engine power of a motor drill in kilowatts. Watts (kilowatts) are a common unit of power, and this unit is also used for gasoline engines along with horsepower (see above).

Power is one of the key parameters for any motor auger: the more powerful the engine, the higher torque can be achieved on the drive shaft, the thicker augers can be used with the unit and the better it is suitable for complex work and “heavy” soils. On the other hand, high power significantly affects the price, dimensions and weight of the engine. Therefore, manufacturers choose this parameter based on the price category and general purpose of the tool.

Indicators of 0.6 – 1.2 kW are typical for the most modest engines, these are mainly equipped with power drills (see "Type"). In entry-level motor drills, more powerful units are used, by 1.2 – 2.2 kW, the average class corresponds to an indicator of 2.3 – 3.7 kW, and in the most solid devices, the power can reach 5.5 – 6 kW. Note that units of the same power may differ in screw diameter and other performance characteristics.

The volume of the fuel tank installed in the drill.

A larger tank allows you to work longer without refueling, but it significantly affects the weight of the tool. Given the peculiarities of the operation of motor drills, in fact it is easier to take breaks for refueling than to keep a large supply of fuel in the unit itself. Therefore, tank volumes are usually small, only in some high-power models this parameter exceeds 2 liters. At the same time, manufacturers take into account fuel consumption and select tanks in such a way that breaks do not have to be taken too often.

The maximum length of the drill (auger) or drill with which the tool is able to work normally; in fact, this is the maximum drilling depth available when using this model. Note that some models allow, if necessary, the use of longer drills, due to some tricks (you can read more about them in special sources); however, this possibility is far from being available everywhere, and when choosing, it is worth proceeding precisely from the length claimed by the manufacturer.

The highest rotational speed of the drill (auger) or drill that the tool can provide.

Rotational speed and torque are inversely related: higher drill speeds (for the same engine power) correspond to lower torque, and vice versa. This means that of two power drills of the same power, the slower one will be at the same time more "torque", able to better cope with heavy work and thick augers (see "Maximum diameter"). On the other hand, a higher speed allows faster material selection and less time spent on work, so for light loads, faster tools are preferable.

The noise level produced by the tool during operation.

The lower this indicator, the more comfortable the use of the tool, the easier it is to work with it without headphones or other noise protection equipment. At the same time, the noise level claimed in the specifications is quite approximate, in fact it can be higher (for example, during overload) and lower (at idle). Also note that the decibel used to indicate the noise level is a non-linear value, so the actual loudness should be evaluated using special comparative tables.

Modern motor drills are quite noisy equipment — even in the most “quiet” models, the volume exceeds 95 dB (loudness comparable to the sound of a moving freight car at 4–5 m), and in the noisiest this figure reaches 115–116 dB (which is only slightly lower human pain threshold; ear protection is highly desirable).