Power consumption
The total power consumed by a mains-powered electric tool (see "Power Source"). It is considered the main criterion for assessing the overall capabilities of a particular model: more power allows you to achieve more speed and/or torque. However a more correct parameter for such an assessment is useful (working) power, but it is far from always indicated, and tools of the same type with similar power consumption usually do not differ much in terms of working power. In addition, data on power consumption also allows you to estimate the load on the power grid or other power source; in some cases this is unnecessary.
As for specific figures, for different types of tools, the characteristic power values will be different. For example,
from 750 to 1000 W is considered a very solid indicator for a screwdriver, while for classic drills this is an average value, among such devices there are options even for
1.5 kW or more. Detailed recommendations on choosing a tool for this parameter can be found in special sources. We only note that it does not always make sense to chase the maximum values high power noticeably affects the dimensions, weight and price of the unit, despite the fact that it is far from always required.
Rotation speed
The speed of rotation of the working nozzle provided by the tool.
If a single number is indicated in this paragraph (for example, 1800), it can be either a standard, constant, or maximum rotation speed. This refers to the maximum speed if the tool has more than one speed (see "Number of speeds") and/or a speed controller (see "Functions"). In turn, two or three numbers through an oblique line (for example, 1100/2300/3400) are indicated only for models that have the corresponding number of individual speeds. Each of these numbers indicates the standard (and in the presence of a speed controller — the maximum) number of revolutions at one of the speeds.
Anyway, when choosing a tool by the number of revolutions, it is worth considering both its general type (see "Device") and the specifics of the intended work. Detailed recommendations on this matter are quite extensive, it makes no sense to give them in full here — it is better to turn to special sources. We note only a few general points. So,
high -speed drills nowadays are considered to be drills capable of delivering more than 3000 rpm. In general, high speed contributes to productivity, but there is also a downside: increasing the speed (for the same power) reduces torque — accordingly, the efficiency of working with stubborn materials and large diameter nozzles decreases. Therefore, it makes sense to specifically look for a "high-speed" tool only if speed is of key impor
...tance; it doesn’t hurt to make sure that the model you choose can provide the required efficiency and torque.Torque
Torque is the maximum force with which this model is capable of turning the working nozzle.
Higher torque gives more options, it allows you to cope with complex tasks such as drilling in hard materials, unscrewing stuck screws and nuts, etc. On the other hand, a lot of force requires corresponding power — and this, in turn, affects the dimensions , weight and cost of the tool itself, and also puts forward increased power requirements (mains power, battery capacity or pressure / compressor performance). And for some tasks, excessive torque is basically unacceptable, so for maximum versatility, it is desirable to have
torque control — and this affects the cost even more. And the more steps, the more optimally you can configure the tool to perform a particular type of work. So the general rule is this: when choosing, it is worth considering the specifics of the planned work, and not chasing the greatest working effort.
Detailed recommendations on choosing the optimal torque for different types of tools (see "Device") can be found in special sources. Here we note that it is of key importance primarily for screwdrivers, although it is also given for other types of tools. At the same time, in the “weakest” models, the maximum working force does not exceed 15 Nm, in the most powerful ones it is more than 150 Nm.
Reverse
Type of
reverse provided in the design of the tool.
The reverse allows you to switch the direction of rotation of the nozzle; see "Functions" for details. It also indicates the type of switch responsible for this function. The varieties of such switches nowadays are very diverse:
slider,
flag,
brush on the engine,
on the start button,
gyroscopic,
on the keyboard toggle switch, and also combined with
a flow switch or
ratchet mechanism. Here is a detailed description of each of these varieties:
— Crawler. Switch in the form of a slider with two opposite positions. Usually, it moves in the direction "back and forth" relative to the tool chuck — this format is considered the most practical. The sliders are quite simple and at the same time convenient and visual, especially when used in screwdrivers and wrenches: by moving forward (away from you), the direction of rotation is set to twisting, by moving backward (toward yourself), respectively, to unscrewing. However, such devices are widely used in other types of instruments (see "Device") and are generally the most popular option nowadays.
— Combined with the flow switch. The most popular type of reve
...rse in pneumatic tools (see "Power Source"); not found in other models. The flow switch itself is actually a speed controller, most often in the form of a distinctive rotary knob or lever. And if this regulator is combined with a reverse, this means that it can deviate from the neutral position in two directions, and the direction of rotation will depend on which direction the flow switch is shifted.
— 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 a checkbox is that it is right at your fingertips and can be toggled with almost no unnecessary movement (which is not always available for a slider). On the other hand, this option is mainly suitable for drills, and in screwdrivers and wrenches, the checkbox is not as intuitive as the same slider. And in general, this type of reverse for a number of reasons is much less common.
— Brush (on the engine). Reverse switch installed directly in the tool motor and based on the use of a special movable brush holder. By changing the position of the brushes in the motor with the help of such a mechanism, it is possible to change the direction of its rotation. One of the key advantages of this method is that it allows you to achieve maximum power in any direction of rotation without any special tricks. In addition, such an adjustment has a positive effect on the engine resource. On the other hand, brush switches are quite complex and expensive, and therefore are installed mainly in a powerful professional tool.
— On the start button. Reverse switch combined with start button. Such a combination button is usually made in the form of a "rocker", and the direction of rotation depends on which side of the rocker the user pressed; pressing the same button immediately starts the engine. This design allows you to easily and quickly change the direction of rotation — for this you do not need to be distracted by individual switches, just move your finger slightly and press the other half of the start button. This is especially convenient for screw and wrench drivers, as well as screwdrivers; in fact, most of the models with this type of reverse belong to these types.
— On a keyboard switch. The control method, in many respects similar to the reverse on the start button described above, also uses a rocker switch. The key difference is that in this case the direction switch is made separately from the start button — that is, the user must first select the direction of movement, and then press "start". This option does not have any particular drawbacks, but it also does not differ in convenience, and therefore it is extremely rare.
— Gyroscopic. A rather rare and specific type of reverse, found exclusively in screwdrivers (see "Type"). In fact, there are no external switches in such a tool — instead, a built-in gyroscope is used to track body rotations. Accordingly, to select the direction of movement, you need to rather sharply turn the tool around the longitudinal axis in the appropriate direction and smoothly return it to its original position (speed can be adjusted in the same way — for example, the farther the turn, the higher the speed will be). This control method is very simple and intuitive, but it is rather complicated in technical implementation and requires increased accuracy in handling the tool. That is why gyroscopic reverse is extremely rare nowadays.
— Combined with a ratchet mechanism. Another rather rare option, found exclusively in wrenches — mostly pneumatic, less often battery-powered (see "Power"). The ratchet mechanism, we recall, is responsible for ensuring that the working part of the tool rotates in only one direction. And the reverse is controlled through a mechanical switch, which is directly connected to this mechanism and changes its settings, setting one or another direction of rotation.Features
—
Impact mode. Ability to work in the so-called shock mode. Usually, this mode is turned on and off at the request of the user, and its meaning and features may be different, depending on the type of instrument (see "Device"). So, in drills, strikes are carried out along the axis of the drill, and their frequency is usually several thousand per minute — this has a positive effect on productivity and allows you to more effectively cope with hard, dense materials (although such a drill can not be replaced anyway). In turn, in screwdrivers and wrenches, it would be more correct to call the impact mode pulsed: in this format of operation, the tool nozzle does not rotate uniformly, but in separate jerks, usually at a frequency of about 3K per minute. It also improves work efficiency, which is especially useful when driving self-tapping screws into dense material and unscrewing old, “stuck” fasteners.
—
Engine brake. A device that additionally slows down the engine when the tool is turned off. The engine itself (and, accordingly, the working nozzle) after turning off can rotate for quite a long time by inertia; the brake stops this rotation almost immediately, so you do not have to keep the tool on weight for too long.
—
Power button lock. A function that allows you to lock the power button in the pressed position. Usually, it looks like an additional button insta
...lled either on the start key itself or not far from it. This function is very convenient in situations where the tool has to be used for a long time without interruption — for example, when drilling several dozen holes at once: it is easier to fix the start button in the on position than to keep it pressed all the time, additionally straining the finger on the working hand. And the lock is turned off, usually, in the simplest way — for example, by briefly pressing the same start button.
— Speed controller. Possibility to additionally limit the revolutions of the tool. By itself, smooth adjustment is available in almost all modern models: the harder you press the start button, the higher the speed. This allows you to directly "on the go" adjust the mode of operation of the tool to the specifics of the situation. And this regulator allows you to set the maximum speed of rotation, so that even when you press the button “to the stop”, the speed of the working nozzle does not exceed the specified value. This function is indispensable for some jobs that require precision — in particular, when processing delicate materials, for which too high a speed is fraught with damage.
Separately, we emphasize that the presence of a speed controller has nothing to do with the number of speeds (see above). For example, a tool may well have several speed modes, in each of which the speed can be further limited using a regulator.
— Maintain momentum. A feature that allows you to maintain a constant speed of rotation of the nozzle, regardless of the load on it. Without special adjustment, at a constant engine power, the rotational speed inevitably drops with increasing load and increases with a decrease. And the revs control system monitors the resistance on the nozzle and, if necessary, changes the power in such a way that the rotation speed remains constant. This has a positive effect both on the quality of work and on the service life of the nozzles and the entire tool.
— Electronic engine protection. A system that protects the engine from critical overloads — for example, in the event of a jammed drill — and overheating. If the motor load or motor temperature is exceeded, the power to the instrument is automatically turned off to avoid damage to the instrument.
— Brushless motor. The presence of a brushless (brushless) motor in an electric tool. Such motors are noticeably superior to traditional collector motors in terms of efficiency, which can significantly reduce energy consumption without sacrificing power; this is especially important for cordless tools (see "Power Source"), where this feature is predominantly found. In addition, brushless motors are quieter and produce virtually no sparks during operation, making them perfect for working in high fire hazard environments. Their main disadvantages are traditional — the complexity of the design and high price.
— Safety clutch. A device that protects the engine from damage during a sharp increase in load (for example, due to jamming of the drill). In such cases, the safety clutch disconnects the motor shaft from the tool chuck, avoiding overloads. Note that such devices can be both reusable and disposable — the latter are destroyed when triggered, and to continue working, you will need to install a new clutch.
— Backlight. The built-in lamp for illumination of a place of work. This feature can be useful both in the evening/night time, and in hard-to-reach places where there is little penetration of outdoor lighting, as well as in situations where this lighting is too dim. Note that in addition to built-in light sources, modern tools can also be equipped with separate flashlights; for more details about them, see "Complete set".
— Display. Own display, which can display various information about the operation and status of the device — for example, the torque or rotation speed set in the settings, and in battery models, there is also a battery charge indicator. Such a screen provides additional convenience and visibility, however, in general, this is a rather specific function that is extremely rare in modern power tools — for example, a speed or torque indicator can be provided directly on the regulator, and a conventional LED can be provided as a charge indicator, giving signals by blinking or colour change.
— Synchronization with a smartphone. The ability to connect the instrument to a smartphone or other gadget (such as a tablet) via Wi-Fi or Bluetooth. Such a connection is usually used to adjust operating parameters such as speed or torque; doing this through a mobile application is often more convenient than through the controls on the instrument itself. And some models with this function also allow you to set password access: the tool simply will not respond to the start button until the correct password is entered on the control gadget.
— Built-in spirit level. Built-in device to control the angle at which the tool is located to the horizon. As in ordinary levels, the role of the scale in such devices is played by a sealed flask with marks applied to it, containing a brightly coloured liquid and an air spirit. By the position of this spirit relative to the marks, the position of the entire tool is determined — namely, its correspondence to the vertical, horizontal, or pre-set tilt angle (the latter option, however, is almost never found in the built-in levels). At the same time, purely hand tools usually provide a single-axis level that reacts only to deviation from the horizontal forward or backward, and models with the ability to mount on a rack (see below) can also have a circular level that controls compliance with the vertical and determines deviations from it in any direction.
— Revolving mechanism for bits. A mechanism for storing and quickly changing bits used in tools for the corresponding purpose — mainly screwdrivers, but also some screwdrivers (see "Device"). In accordance with the name, the main part of the mechanism is a drum like a revolver, in the compartments of which the bits are stored. The mechanism is located behind the cartridge, and the choice of bits usually occurs as follows: you need to pull back a special casing or handle (if at that moment there was another bit in the cartridge, it will return to the drum), by turning the drum, select the compartment with the desired nozzle, and then move the casing / handle to its original position by pushing the nozzle out of the drum into the chuck. This feature significantly speeds up and simplifies the replacement of nozzles, and also reduces the risk of losing them. On the other hand, the revolving mechanism significantly affects the price and weight of the tool, and its capacity is usually limited to 6 – 8 nozzles. Thus, such a tool is usually also equipped with an adapter for installing bits in the traditional way, from the outside of the cartridge.
— Water cooling(coolant). The tool has a coolant — a liquid cooling system (most often plain water) supplied to the working nozzle using a built-in pump. Such a system performs several functions at once. Firstly, it actually cools the nozzle, preventing damage due to overheating. Secondly, the liquid somewhat reduces friction at the point of contact, further reducing the load on the nozzle and increasing its durability. Thirdly, water absorbs dust generated during drilling, this dust does not fly into the air and does not enter the lungs of people around; and cleaning up after work is much easier. On the other hand, water cooling systems are quite expensive and bulky, and with relatively simple work and low loads, it is quite possible to do without coolant.
— Soft start. A function that provides a smooth spin-up of the tool motor, with relatively little acceleration. This is achieved by limiting the starting current. Without such a limit, the current drawn by the motor at the time of starting can be quite high, causing the motor to start very abruptly, which increases the risk of letting go of the tool. In addition, current surges can lead to overloads in the network used for power. Soft start allows you to eliminate these phenomena to some extent. Note that it is used only in mains-powered models — the motors in cordless tools are not so powerful that they have the actual “troubles” described for them.
