How to change brushes on a pit screwdriver


Do not rush to disassemble the screwdriver when the chuck does not rotate when you press the start button. Start simple. replace the battery with a known good and fully charged one. If there are no changes, remove the battery, unscrew the screws from the case and disassemble it. Measure the resistance between the brushes with a multimeter. With wear not exceeding the permissible level, they will have good contact with the collector, and the device will show a resistance close to 0. If the readings are more like an open circuit than a short circuit, knock on the brush holders with the handle of a screwdriver and turn the motor rotor by hand several times. A persistent tester reading will indicate that contact has not recovered and the instrument requires repair. Making such a check is easier than disassembling a motor, especially an unmaintained one. It should be noted that the symptoms of breakage of the armature windings and wear of the brushes are the same. But winding breakage is an extremely rare event, wear is much more common.


change, brushes, screwdriver

It’s simple on a serviced engine.

  • Disassemble the case
  • Take out the worn out kit
  • Put a new one
  • Assemble the case

The maintenance-free motor is distinguished by the rolling of the rear ends of the holders. Often the lid, on the inside of which they are located, inserted into the body, is fastened by rolling. Here, the process is somewhat more complicated.

  • Use pliers to bend the flare that holds the cover
  • On the perimeter of the cover and body, mark 3 points equidistant from each other
  • Take out the cover
  • Using soldering fat, solder and a powerful soldering iron, irradiate the marked points
  • After cutting the stranded wires, replace the worn brushes with new ones.
  • Solder the wires coming from them to the holders. Then, in order not to break the copper. graphite contacts when installing the lid, alternately drown them in the holders and fasten each in this position with a thread, tying it with a bow
  • Leaving the ends of the threads outside, install the cover into the body
  • Re-establish contact in the control room by undoing and pulling the threads
  • Solder the cover to the motor housing


Motor brushes are contacts through which current is supplied to the rotor windings. Since the rotor is designed to rotate, it is not possible to supply current to its windings through a fixed wire connection. For this, a collector-brush assembly (KShU) is used. The collector consists of copper plates attached to an insulated section of the armature shaft. The terminals of the rotor windings are connected to them. The brushes are attached flush to the collector. As the rotor rotates, they slide over the collector plates. Current flows alternately through these sliding contacts in the armature windings. The resulting alternating magnetic field is the force that rotates the rotor.

Knowing how the unit that feeds the armature windings works, it is easy to guess that its parts must wear out. The rotor is complex and expensive to manufacture. Therefore, to protect it from wear and tear collector, the material for making the brushes is deliberately chosen to be less abrasion resistant. Otherwise, it would not be necessary to replace the brushes, but the anchor. Another essential property of brushes should be good electrical conductivity. Better than others, these conditions are met by a mixture of copper powder with graphite. Electric motors with a lower power or higher operating voltage than a screwdriver can be equipped with graphite brushes. And graphite is not suitable for a screwdriver motor with low operating voltage and high currents due to the electrical resistance that is too high for it.

Replacing brushes on a screwdriver on your own

The reason that the screwdriver stopped working is often excessive wear of the brushes of its electric motor. It is not difficult to eliminate such a malfunction, but minimal knowledge of the DC motor is required. Let’s start by defining what brushes are.

About labor costs

Repairing a screwdriver with a serviceable motor can be done relatively quickly. The same cannot be said about restoring a device that cannot be repaired. Think, maybe, in the time it takes to repair, you can make money by doing what you do well enough to buy a new one. After all, you don’t need to learn something to do it just once.

Preparing the screwdriver for work

To bring this device into working condition, it is necessary:

Pull it out of the case and inspect for visible damage. cracks on the case, etc. If they are found, use the tool is prohibited.

After inspection, dock the battery to it, and then make sure that there is enough charge to start work. If the battery slowly rotates the tool spindle, you need to remove the battery and put it on charge (see below for how to recharge the battery), and connect another battery to the tool instead.

After making sure that the battery has gained a sufficient charge, the required nozzle is installed in the screwdriver, depending on the nature of the work (tightening screws or drilling) and the size of the screws. We will tell you in detail about installing the attachment further, but here we focus on the fact that for the safety of work during installation or replacement of the attachment, the battery must be removed so as not to accidentally turn on the screwdriver.

Using the knobs on the instrument, you can select:

  • operating mode. drilling, working with screws, in some models there is also an impact mode, for example, Bosch GSR 180-LI.
  • the speed of rotation of the nozzle (if the model of the tool has several stages of rotation, for example, Makita DF347DWE); direction of rotation. for drilling and screwing screws clockwise, for unscrewing screws. counterclockwise.

If you are going to drill to a certain depth, then in models of screwdrivers where there are limiters on the drilling depth, you must set it.

Remember that the correct preparation of the tool is the key to the safety of working with it.

How to store a screwdriver

Better separate from the battery. If you have a model with a nickel-cadmium battery, then before ending work and disconnecting the battery, it must be completely discharged. After removing the battery, it must be charged. Remember that Ni-Cd has a high self-discharge current, therefore, during long-term storage, it needs periodic recharging.

Charging the screwdriver

The most important part of the operation of the tool, on which the duration of the device’s operation largely depends. How to charge a screwdriver battery depends on its type. The most common lithium-ion batteries. Such a battery with its compact dimensions quickly charges and does not have a memory effect. The main disadvantage is a quick discharge in the cold and a high price.

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Older models have nickel-cadmium batteries. They are cheap, reliable, but have a memory effect. That is, if you do not completely discharge them before charging, then gradually the battery capacity will decrease.

How much you need to charge the battery depends on its type and capacity. Li-Ion batteries gain charge most quickly. The battery of a household screwdriver takes an hour to charge. The same capacity Ni-Cd battery will charge for 7 hours.

How do you know if a screwdriver is loaded? The charger has an indicator, for example, for the DeWalt 572576-01 model, it is on the right. The red light is on. the battery is being charged, the green light. can be used. You can also focus on your own experience. By the charging time and the nature of the screwdriver’s work, you can judge the charging of its battery.

If you have a model with a nickel-cadmium battery, then you should know how to swing a screwdriver battery, which will inevitably decrease its capacity after several years of use. And if you use the tool incorrectly, that is, do not bring the battery to full discharge before charging, then faster.

In order to restore capacity, you need to know how to discharge a screwdriver battery correctly. And this means a smooth decrease in the charge, by connecting to it a twelve-volt light bulb with a power of 25.40 watts. After a complete discharge, charge the battery to the eyeballs and then discharge it again. Repeat the procedure at least 5 times. The capacity cannot be fully restored by such a procedure, but the operating time of the screwdriver can be significantly increased.

Equipment installation

The screwdriver can be equipped with drills or nozzles for twisting and unscrewing screws. When the desired bit is selected, it is necessary to rotate the chuck sleeve counterclockwise until its jaws are separated by a distance sufficient to insert the drill shank or screw bits between them. Then the clamp is made in the reverse order. There are two types of cartridges:

  • the clamp is made without a key, but only by rotating the cartridge case by hand;
  • requiring pressure with a special key, which is inserted into the recess in the chuck and rotates it, leaning against the toothed rim, for example, as in the Dnipro-M 1/2 ″ x20 gear chuck.

How to remove a chuck from a screwdriver, for example, to lubricate it or replace it if it does not fix the nozzle poorly. In modern models, the chucks are screwed onto the shaft and, for reliability, are locked with a screw with a left-hand thread. This is how the cartridges are attached in Makita, Bosch, etc. screwdrivers. It is necessary to unscrew the screw and unscrew the cartridge by rotating counterclockwise. Detailed instructions on how to do this are available in the documentation for the tool.

Do I need to lubricate the screwdriver

This tool has a gearbox and it requires lubrication such as ELF MULTI MOS. The frequency depends on the model and the intensity of use. The following signs will indicate that your tool needs lubrication:

  • unpleasant “tearing” sound;
  • the chuck is difficult to rotate by hand.

You can lubricate with lithol, manol, silicone or Teflon grease.

Is it possible to drill with a screwdriver

If you have a model that has two modes of operation. drilling and a screwdriver. Usually professional models have such capabilities, for example Makita DF347DWE. It is not necessary to use a model that does not have a drilling mode, the engine may burn out, since drilling requires higher revolutions to reduce the load.

Is it possible to cut a thread with a screwdriver

It is possible, but with reservations. Firstly, small diameters, up to 10 mm. You will definitely not cut a thread on a ¾ ”pipe. Secondly, only internal. You will not install the die on the screwdriver. Third, skill is required. A slight misalignment and that’s it, either break the tap or just ruin the thread. Minimal cutting effort!

Screwdriver bits: general information, basic tip types

Like removable attachments for drills, screwdriver bits belong to the category of devices that are aimed at expanding the functionality. Thanks to them, this tool can be turned into a universal screwdriver or a compact machine for cutting sheet metal. The range of handpieces offered by manufacturers is very wide. With their help, you can carry out construction work of any complexity at home, which ensured such popularity of the screwdriver.

To choose the right bits, you need to know the classification of products in this group.

Some buyers don’t see the difference between a drill and a screwdriver, but there is one. over, these differences must be taken into account when choosing removable nozzles for performing certain jobs. Firstly, the rotational speed of a screwdriver is much lower than that of a drill. Secondly, it lacks a moment of inertia. In other words, if you press the shutdown button, the screwdriver will instantly stop, unlike a drill, which will rotate for some time.

All screwdrivers have a release clutch. It is designed to adjust the tightening force. Some models do not have a cartridge. Instead, a hex socket is installed in which the bits are fixed.

There are several types of tools, each of which can provide specific benefits:

  • Small screwdrivers. used as a miniature electric screwdriver for repairing watches, phones and small appliances.
  • Folding screwdrivers. these models are designed to work in a confined space that a regular tool cannot reach. If the handle interferes during operation, you can simply remove it.
  • Drill drivers are designs that are hybrids. They combine the best properties of each instrument.

Working attachments for a screwdriver can be purchased in sets or individually

Important! When working with a screwdriver, it is advisable to use protective equipment. This is especially true for operations such as grinding and polishing, during which fragments and dust are formed.

Varieties of screwdriver attachments for self-tapping screws in tape

To fix self-tapping screws with a screwdriver, not only bits, but also tapes can be used. They are part of the automatic fastener feed devices. Such attachments allow to speed up installation work by about 2-3 times. The advantage of using them is that the master does not need to take a new self-tapping screw every time and install it on the bit.

To fix self-tapping screws, not only bits, but also tapes can be used

Manufacturers produce two types of drives with a tape feed mechanism for self-tapping screws:

  • Removable tape attachments for a screwdriver. if necessary, such a tip can be removed and additionally screwed on the self-tapping screw. This option is in high demand among consumers, although it is not without its drawbacks. The fact is that the attachment must be bought together with a screwdriver.
  • Stationary mechanisms. in this case, the attachment together with the screwdriver is a one-piece structure. Such a tool belongs to the category of narrowly targeted and can only be used with tapes.

Tape screwdrivers are battery and mains. Devices that plug into an outlet cost half the price. However, they are completely dependent on the power supply and are not so convenient to use, since the hanging cord creates certain inconveniences. This is especially true when installation work is carried out on the ceiling.

Helpful advice! To increase the efficiency of polishing, the disc of the attachment must be lubricated with a special polishing paste.

There are two types of drives with a tape feed mechanism for self-tapping screws: stationary and removable type

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Characteristics of screwdriver rivet bits

Traditional one-piece rivets are rarely used. Many professionals prefer to use a welding machine. However, not every master has such equipment in his arsenal, and also has the skills necessary to work with it. In this case, the best option would be a rivet attachment, which is installed on a screwdriver.

Screwdriver bits for rivets can only be used on models with a reversible drive

Such attachments can be used on electric and cordless tools to install nut-type rivets and other fasteners that have a core.

It should be noted that screwdriver attachments for rivets can only be used on those tool models where there is a reversible drive. These fixtures are designed for mounting aluminum or steel fasteners, the diameter of which is in the range of 2.4-5 mm. They can also be used to install sleeves made of non-ferrous metals, the diameter of which does not exceed 25 mm.

If a battery-powered screwdriver is used to install the rivets, you need to make sure that the battery voltage does not exceed 12 V. The installation process itself is not particularly difficult, and the attachments are compact enough to be stored together with the screwdriver in one case.

Screwdriver bits: functional tips for power tools

Screwdriver attachments greatly facilitate repair and construction work, since the process of assembling and dismantling various structures is simplified through the use of this convenient and useful tool. Removable devices allow you to expand the scope of its application, in this article you can familiarize yourself with the features of the most demanded of them. The text contains brief overviews of accessories designed for working with wood, metal and drywall.

For each type of fastener, you need a suitable bit for a screwdriver

The main types of polishing and grinding attachments for a screwdriver

The polishing and grinding attachments for the screwdriver are a large group of removable accessories, including many varieties. In this category, you can find handpieces for a variety of tasks:

  • polishing metal, wood and glass surfaces, as well as varnished products;
  • cleaning products made of metal from corrosion and remnants of old paintwork;
  • grinding wood and metal surfaces.

Thanks to the huge variety of screwdriver attachments for grinding, you can choose tips for operations that cannot be done with standard methods.

Overview of screwdriver attachments for cutting sheet metal and plastic

The disc shears are equipped with two steel discs. One of them rotates due to the rotational motion transmitted from the chuck to the tool. The design of the cutting disc for the screwdriver is designed in such a way that the metal is cut along a straight mowing line, even without marking.

Disc shears are used in cladding and roofing works using:

  • metal tiles;
  • galvanized;
  • siding;
  • metal profile.

Note! Circular shears are maneuverable enough to create curly sections, but they cannot cope with the manufacture of complex metal parts.

The nibbler for metal screwdriver is an attachment that has high maneuverability and allows you to get a very accurate cut. The edge turns out to be as smooth and neat as possible, so the possibility of cutting your hands when working with metal is almost completely eliminated.

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Disc shears are used in cladding and roofing works

Turbo scissors. a screwdriver attachment that works on the same principle as conventional scissors, but cutting is much faster. This device is suitable for cutting sheet metal, plastics and other materials with a high degree of rigidity. The advantage of this nozzle is that there is no vibration during operation. This ensures that the back of the claw does not damage the surface it touches.

This concludes the list of attachments for a metal cutting screwdriver. Sector-type scissors are used in the installation of communication systems. They are suitable for cutting plastic pipes as well as power cables.

The main types of angle adapters for a screwdriver

Angle adapters allow you to unscrew and tighten fasteners in hard-to-reach places. Such nozzles greatly simplify the work, because the tool can be held perpendicular to the surface, and the screws can be screwed at an angle, both to the left and to the right.

Angle adapters make it easier to work in tight spaces

Taking into account the technical characteristics, as well as the functional purpose, there are two types of angle nozzles for a screwdriver:

  • flexible;
  • tough.

Flexible design attachments use a flexible connection to change the direction of the torsion axis. Outwardly, the device looks like a drill used in dental clinics for dental treatment. The removable tip consists of a flexible shaft that connects the work bit to the chuck of the screwdriver. This type of attachment makes it easier and faster to work in hard-to-reach places where you need to unscrew the screws.

Note! Flexible angle attachments for a screwdriver are not suitable for fasteners that are made of strong alloys.

Rigid adapters are short attachments that mechanically change the direction of the axis of rotation. Unlike the previous version, the cartridge of this device is much stronger. Rigid adapters allow mounting and dismounting of fasteners from either side. Such attachments are usually used in professional screwdrivers, the motor of which is designed for high loads and strong vibrations.

There are two types of screwdriver angle bits: flexible and rigid

Checking the electric motor: causes of breakdowns and repairs

There are several reasons for drill armature or stator breakage. First of all, this is the illiterate operation of the device. For example, many users simply overload the tool, carrying out work without interruption. This leads to the fact that the drill motor does not have time to “rest”. The second reason lies in the poor winding wire, which is often found in cheap models. That is why breakdowns of cheap tools are much more common. In this case, repairs must be carried out using a specialized tool. And it will be better if you entrust this work to professional specialists.

However, if it was decided to carry out the repair on its own, you will certainly have a question. how to do everything right? As you already understood, an electric drill “suffers” from breakdowns of the armature and stator, and this can be checked by several signs, for example, when the tool suddenly sparks during operation. If there are no “bright” signs, you can use an ohmmeter.

The stator is changed like this:

  • First, carefully disassemble the device case;
  • We remove the wires and all internal parts;
  • After finding out the reasons for the breakdown, we change the spare part to a new one, close the case again.

Required tools and materials

Drill repair can be carried out on your own, the main thing is to know the causes of breakdowns and methods of their “treatment”. Today we will talk about how the drill button connection diagram looks like, we will not ignore other malfunctions, thanks to which you will be the happy owner of a working tool.

Drill button connection diagram. how to fix the problem?

Unfortunately, a tester will not be enough for you to check the performance of the tool, which is due to the fact that most of the buttons of the device are equipped with a smooth speed control, and therefore a conventional tester may give you incorrect data. In this case, you will need a special wiring diagram for the drill button. Often in tools, one wire is connected to a terminal, and therefore pressing the button at the same time leads to ringing of the terminals. In the event that the light comes on, everything is fine with the button, but if you notice a malfunction, it’s time to replace the button.

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When replacing, keep in mind that the circuit can be either simple or with a reverse. Due to this, all work on replacing the button must be carried out exclusively according to the scheme, without adding anything “from oneself”. So, the part must be suitable in size and correspond to the power of the tool. At the same time, calculating power is a fairly simple exercise. We use the formula P = UI (taking into account that the power of the drill is 650 W), I = 2.94 A (650/220), which means that the button should be 2.95 A.

How to connect the drill button yourself?

Despite the fact that this process is quite complicated, you can do all the work yourself, observing some important rules. For example, remember that opening the case can cause all parts and loose parts to simply fall out of the case. Naturally, this should be avoided, because then it will be quite difficult to put the device together. To do this, you can gently lift the cover, noting the exact location of the spare parts on paper.

The button is repaired as follows:

  • First, the clips for the casing are hooked, after which it is carefully pulled together;
  • All rusted and darkened terminals are cleaned of carbon deposits, for which you can use alcohol or sandpaper;
  • We reassemble the tool, making sure that all the parts of the device are in place, and we check the performance of the drill. if nothing has changed, we change the part;
  • We fill the turnover regulator with a compound, and therefore, if the part fails, we simply replace it;
  • A frequent breakdown is the erasure of the working layer under the rheostat. it is better not to repair it, just waste your time, it is better to buy a new one and replace it.

Many are interested in where to get such a scheme? First of all, it should come with the tool when you buy it, but if there is no scheme, or you have lost it, you will have to search the Internet. After all, only with its help you will be able to carry out the repair correctly, without errors. By the way, the speed control button and the reverse control button are located in different places, and therefore they will have to be checked separately.

Possible tool malfunctions. we carry out repairs ourselves

If your tool began to work worse, or completely stopped performing its direct duties, it’s time to diagnose the malfunctions and try to cope with them. First, we check the wire for damage and voltage in the outlet, for which you can turn on any other device. a TV or a kettle.

If you are inspecting battery-powered devices, you need to check them when using the tester. in this case, the voltage indicated on the case should have the same value as the battery voltage.

If the voltage is less, you will have to replace the batteries with new ones. If the battery is working properly, the power supply is normal, look for problems in the hardware. The most common breakdowns are:

  • Problems with engine operation;
  • Wear of brushes;
  • Problems with button operation.

Knowing how the electric drill button is connected, you can quickly solve the problem. In addition, a problem with the operation of the drill may arise due to the dustiness of the tool, because the drill “takes” wood, brick, and other materials. This means that you should take care to clean the device after each use. this is the only way to reduce the risk of malfunction due to dirty tools. That is why after you have carried out repairs in the apartment, immediately clean the drill.

Drill button connection diagram. we fix the tool ourselves!

How to replace brushes: work in a couple of minutes

But the drill may not work due to trivial malfunctions. for example, because of the brushes inside the motor. This means that you cannot do without repairing brushes, while this work is quite simple. you do not even need to have special knowledge and tools. To do this, we disassemble the device, remove the brush holders from it and change the parts that are broken. By the way, there are models, the body of which can not be disassembled. in them you just need to remove special plugs through the installation window, after which we change the brushes.

As you can see, there are various breakdowns, many of which will be subject to you, others will be feasible only for specialists in service centers. And in order to reduce the risk of such breakdowns, you need to take care of your tool, clean it after work, check the condition of parts and brushes in order to replace them with new ones in time. However, if you see that you cannot handle it yourself, take the device to the workshop.

Cordless screwdriver PIT PSR 14.4-D1

Cordless screwdriver PIT PSR 18-D1

Benefits of the PIT technique

The PIT brand was created in 1996 and today it is widely represented on the market of Russia, the CIS countries, as well as Europe. PIT differs from other Chinese manufacturers in higher quality: all components are produced within the same enterprise and undergo a strict control procedure. The range of products includes gasoline and electric equipment, welding equipment, machines for various purposes, as well as spare parts.

In the not so distant past, the big name of the brand played a decisive role, but today consumers value a reasonable price-quality ratio. Therefore, PIT brand instruments are popular among professionals and amateurs. Inexpensive, but strong and durable devices perform their functions at the proper level, and solid build successfully competes with more famous brands.

In addition to quality, comfort during work also plays an important role. Ergonomic grips with rubber and silicone inserts allow convenient placement of tools in the hands, so craftsmen are less tired.

Cordless screwdriver PIT PSR 12

This group includes several models, the most popular of which are: D, D-1, C-6, C-7. The difference between the two is in terms of maximum torque and rpm: models with the C mark are more powerful and faster, although not by much. Reviews of the PIT screwdrivers are positive. Customers love their lightness, comfortable rubberized grip, durability and efficiency at a low cost. The disadvantages of the PSR 12 model include a tight gearshift button and a fragile case. This tool is great for home use, furniture assembly, screwing in self-tapping screws.


This tool is distinguished by impressive power: rotation speed is from 450 to 1450 rpm, voltage. 24 V, and the maximum torque. 40 Nm. However, the greater weight makes the device less maneuverable, and with prolonged use, the hand starts to get tired. Reviews of the PIT 24 screwdriver indicate that it is used mainly in professional activities and is used not only for tightening self-tapping screws, but also for drilling. Wide functionality means a higher cost, so DIYers rarely choose this model.

Despite the fact that the tool is made in China, its quality remains consistently high, so professionals and amateurs are satisfied with the purchase. Reviews of PIT screwdrivers confirm the benevolence of buyers and pay tribute to their durability, endurance and practicality.