How to choose a cordless screwdriver: 6 tips and a rating of 5 cool models How to choose the right cordless screwdriver for your home? We study the characteristics, manufacturers and additional functionality. Read the detailed guide on MOYO.UA!
In branded models, the manufacturer, in addition to the standard features, also offers the user auxiliary functions. They greatly facilitate the work and can become a point above i, dispelling doubts whether it is worth buying this or that model.
Most often found in tools:
- The charge indicator is a small lamp that will tell you when to put the battery on recharge;
- Reverse and unscrew the screw, and the drill can be removed from the thick board;
- The impact mechanism is indispensable if you need to work with a stone surface or brick;
- Illumination of the workplace for some screwdrivers is so powerful that there is no need for additional lighting.
There is also an impulse, various blockers, speed switches, etc. Each additional function is a plus to the price of the device, which means that you need to be 100% sure about its need in the device.
The numbers in the characteristic show with what force the screwdriver twists the self-tapping screw or how much force is required to overcome the load during drilling. What is the practical use of knowing the parameter? The diameter and length of the bolt to be screwed in depends on the torque. The higher the indicator, the longer and thicker the screws can be used in work without fear of failures or breakdowns. For example, at 40 N / m, it will be possible to freely drive a self-tapping screw 10 cm long into the tree.
In small household models, the torque is from 10 to 30 N / m, but the indicator can be adjusted by adjusting to the nozzle. For adjustment, a stop ring is provided on the screwdriver body, which goes immediately after the chuck. The user can coordinate the effort for a specific screw by scrolling the limiter. Result: as soon as the self-tapping screw is tightened to the desired level, the chuck will stop, although the motor will still work.
Interesting: The stop not only helps to tighten the bolts, preventing excessive sinking into the material, but also protects the tool from wear.
The hackneyed truth is a brand beyond competition. Yes, branded tools are more expensive, but they have a quality guarantee and service centers for repairs, and the screwdrivers themselves are made of durable components.
Quite good screwdrivers with a removable battery are also offered by Varo Kreator, Sparky, Dnipro-M and others.
To choose the ideal device for specific purposes, you should pay attention to the number of revolutions. The manufacturer calls this parameter speed or rotational speed. It is adjusted by pressing the trigger, the harder you press, the greater the speed. In addition, the frequency shows whether the tool will be able to drive a screw into a dense material and what is the approximate diameter of the hole if the screwdriver replaces the drill.
If the customer is confident that the device will only be used for tightening screws and bolts, 500 rpm is more than enough. Screwdrivers acting as drills operate at 1200 rpm.
Nuance: there are models with 1, 2 and 3 speeds on the market, where one is for self-tapping screws, the second is for drilling small holes, the third is for working with metal or other durable raw materials.
Voltage and other parameters
For an ordinary buyer of a screwdriver, it is enough to know:
- For household appliances, the voltage ranges from 10-14 V;
- For professional, the indicator should be more than 18 V. Some instruments boast a level of 36 V.
The next characteristic is power. The parameter informs the user about the speed of the device. It is logical that the higher the power, the faster the screw will be screwed in. But you should not overdo it, for household purposes and do-it-yourself flow repairs, a 500-700 W model is quite enough.
In order not to send the device for charging every half hour of operation, you should pay close attention to the battery. Modern screwdrivers use:
- Lithium-ion batteries are not subject to self-discharge, the most common. They can be charged up to 3000 times, and at any stage and discharge level.
- Nickel-cadmium are not afraid of cold, they work efficiently at subzero temperatures. However, there is a slight downside to self-discharge. You need to store such a battery with 0% charge in order to save capacity to the maximum.
- Nickel-metal hybrid eco-friendly batteries found in some European brands. These batteries are compact and lightweight, but they are frost-resistant.
When comparing battery specifications, it’s also worth looking at capacity. The autonomy of the device and the number of possible recharges depend on it. Over time, the capacity decreases, this also needs to be taken into account.
How to choose a cordless screwdriver: 6 tips and a rating of 5 cool models
A screwdriver is essentially an electrical substitute for a screwdriver. It performs the same functions as its younger brother, only makes the process of tightening / unscrewing screws and bolts much faster. Such a tool is especially effective if there are tens or even hundreds of screws. The device can not only twist the screws. By installing a special drill, you can make holes in wood, plastic and thin metal with a screwdriver. powerful devices even take bricks and concrete. In general, the tool is indispensable in everyday life and during repairs.
Why the screwdriver does not work
Repair or installation of furniture is in full swing, and the screwdriver has stopped working. Let’s consider the main causes of breakdowns and how to repair a screwdriver with our own hands (it will also help us with this). To answer the question why the screwdriver does not work, and how to repair it, you need to have an idea about the device of the screwdriver, its main units, among which the following can be distinguished: a gearbox, a reversing device, an electric motor, a speed regulator and if the tool is a self-contained battery (charging battery ).
over, both expensive and cheaper screwdrivers basically have a similar device, which differs from each other by the presence of certain advanced options. From here, we can single out the main reasons why the screwdriver does not work, which almost all models suffer to one degree or another:
- The first thing you need to pay attention to is the serviceability of the battery or the breakdown of the electrical cable from the network (mains screwdriver).
- Failure of the trigger button of the tool.
- Not regulated or poorly regulated engine speed.
- Impossibility of reverse switching.
- Chuck runout.
- The electric motor does not turn.
Run-out of the screwdriver chuck
The runout of the screwdriver chuck indicates that there is a problem with the tool’s gearbox, which is located just behind the motor. This is another reason why a full recoil screwdriver does not work.
Screwdriver Planetary Gearbox Parts
The output shaft of this gearbox is the place where the chuck is fastened, so if we talk about the runout of the chuck itself, you need to keep in mind the runout of the gearbox shaft. The reasons for this may be the following:
- A) bending of the gearbox shaft;
- B) wear of the gears of the reducer;
- C) failure of the support bearing of the gearbox shaft;
- D) the maximum output of the pins, on which the planetary gear satellites are attached.
All of the above parts are of factory origin and cannot be repaired. The problem of beating the screwdriver chuck in this case is solved by replacing the gearbox parts with new ones.
Screwdriver reversing switch
The screwdriver’s reversing switch plays an important role when performing work on screwing in self-tapping screws, as well as removing them if necessary. The electric motor reverse circuit is located in the same housing with the speed controller, and the speed redirection switch itself is located in a convenient place on the handle.
Start and reverse buttons located nearby
Switching is carried out by changing the polarity on the terminals by moving the reverse button. Repairing the entire reverse circuit, including the PWM generator located on the board, boils down to cleaning the switch contacts and replacing the reverse circuit with a new one.
DIY screwdriver repair
About the device of the screwdriver, read the article The device of the screwdriver.
The screwdriver may not turn on for three main reasons: the battery is faulty (not charged), the power button is faulty, the engine brushes are worn out, or the anchor itself burned out (very rarely).
Battery. The battery is checked by a simple measurement at its DC voltage terminals with any tester. The output voltage of a working charged battery must correspond to that indicated on the case. 12V, 18V, etc. Otherwise, the battery must be replaced. The charger of the screwdriver may also be faulty.
Regulator of turns and reverse. The screwdriver speed controller is checked with a multimeter in continuity mode. It should be noted that if the button is fully pressed, the contacts are closed in it and the voltage is supplied to the engine (for reverse) directly, excluding the speed controller circuit. Two wires from the battery come to the button, after which two wires are connected to the engine through the reverse contacts. The power button may still have three wires for connecting a regulating element (field-effect transistor), which is placed outside the body. For continuity, the probes are connected to the input and one of the engine wires (if possible, to the reverse input contacts) alternately, then the button is pressed all the way. The device shows the presence or absence of contact, after which the second input wire is measured. We translate the reverse lever and repeat the measurements. If there is no contact, the button changes.
Repairing a screwdriver button with your own hands is possible, but only if you have certain skills. It is important to understand that after opening the case, many switching parts will simply fall out of the case. This can be prevented only by smoothly lifting the lid initially and the desired sketch of the location of the contacts and springs. If darkened contacts are found, they are cleaned with sandpaper. After assembly, repeated measurements are carried out and if the results are positive (there is contact), the button is installed in its original place.
It should be noted right away that if, after repairing the button, the screwdriver motor starts working when the button is fully pressed, and when it is smoothly pressed, the speed does not adjust, then the reason should be sought in the adjustment scheme. Most screwdriver repairs in this case come down to replacing the entire button.
If there is no reverse, replace the reverse switch or try to repair it. To do this, open the switch cover and, as is the case with the button, carefully lift it. We check contacts, clean and collect. If the contacts are burnt or deformed, the reverse must be replaced. There are variants of buttons, in which the reverse is assembled inside the button body, in this case the entire button is changed.
If, when the button is released, the engine continues to rotate, and before it did not rotate, in this case it is necessary to pay attention to the speed regulator, namely, to the regulating transistor. It is necessary to replace either the entire button or the transistor separately.
Electric motor. If all of the above operations have shown the health of the elements, then it is necessary to check the condition of the engine brushes. To do this, the motor is disconnected from the button, and the multimeter probes are connected to the motor wires. The absence of low resistance in the chain indicates wear on the brushes, but an armature breakage (winding breakage) should not be ruled out, although this happens very rarely. Usually, in this case, the motor changes entirely, but if the brushes are worn out, it is possible to restore the screwdriver motor independently. On some motors, the brushes can be replaced without disassembling the motor. For others, it is necessary to separate the rear motor cover with brushes from the motor housing.
To do this, it is necessary to bend the cover plate, but in such a way that the edges do not break off, as they will need to be returned to their place after assembly. The flexible wire of the brushes is connected to the holder using spot welding, but the wires of new brushes can be soldered, but only with refractory solder, for example, POS-60. Before assembling the motor, the brushes are removed in the brush holder with a clip made of thin wire, the cover is put in place and the wires are pulled out, thereby freeing the brushes. Next, go around the edges of the case in order to firmly press the back cover.
Extraneous whistles and squeaks during operation of the screwdriver can be caused by wear of the armature bushings or a detached magnet that comes into contact with the armature. In the first case, you can extend the life of the engine by dripping a drop of precision instrument oil onto the bushings, and then turning on the engine so that the oil is dispersed through the bushings. This method can only extend the life of the engine, but over time you will still have to replace it.
Reducer. From the long operation of the screwdriver under heavy loads and with lateral pressure, the gearbox shaft is curved, on which the cartridge is screwed, a strong runout appears during the operation of the screwdriver. The bearing bushing or bearing of this shaft can also wear out. If only the bushing or bearing is damaged and the shaft is not bent, then you can try to replace only the worn parts.
It may happen that the engine starts up for a split second and stops abruptly. Everything indicates a breakdown in the gearbox, usually a broken pin on which the satellite is attached. You can try to replace the carrier or the entire gearbox. Failure of the gearbox often occurs due to wear of the gear teeth. A detailed description of the screwdriver gearbox device can be found here.