Brushes
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.
Replacement
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
Diagnostics
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.
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.
How to determine the method of fastening on a screwdriver
The method of fastening is easy to recognize if you carefully examine the parts. The cartridge of the Morse taper variety will have the following inscription: 1-6 B10. This means that in the chuck, it is permissible to fix nozzles with a shank diameter of 1-6 mm, and B10 is an indicator of the size of the Morse taper.
The cartridge, fixed by means of a threaded fastener, is marked:
- Metric thread (domestic products). 1.0-11 М12х1.25
- Inch thread (foreign production). 2-13 mm ½-20 UNF
How to remove and change the cartridge
If you are faced with replacing the cartridge, initially, you should figure out how to mount it. To carry out the procedure with a minimum of effort, experts do not recommend overloading the screwdriver in everyday use. If you operate the tool for fifteen minutes without interruption, the rotating parts may overheat and become firmly seated in the socket. Then it will be more difficult to carry out the replacement. Experts recommend the tried and tested methods for removing the cartridge, described below:
- Unscrew the threaded fastener with an L-shaped hexagon, which is sure to be found in every owner. Next, insert the hexagon (size. 10 mm), place the short edge into the chuck and squeeze tightly in the jaws. After that, start and immediately turn off the device at low speeds so that the free edge hits the table slightly, thus the thread will loosen and you can unscrew the chuck.
- If the chuck is threaded with a locking screw, then:
- Unscrew the left-hand screw clockwise.
- Then insert the hexagon into the cams, and with a quick movement of the hand or hammer, turn the free edge against the clockwise movement. Now you can unscrew the cartridge.
- If both methods didn’t work:
- We take out the shaft from the open housing, on which the gearbox and the cartridge are located. To remove the cartridge, you need to use a pipe wrench.
- To remove and change a chuck with a Morse taper, you need to have a hammer with you, with which the shank will be released from the housing socket.
Chuck Removal: Makita Screwdriver
Typically, Makita brand power tools are equipped with a threaded fastener with an auxiliary fixation by means of a left-hand thread screw.
A number of actions should be followed:
- Unscrew the fixing screw (clockwise).
- Activate the spindle stop button.
- Wrap the body with a thick cloth and squeeze in a vice.
- Clamp the hexagon in the cams.
- Striking with a hammer on the free plane of the key, the chuck is scrolled and then removed from the shaft.
Chuck fastening methods
Chucks are most often attached to the shaft in the following ways:
- By means of a Morse taper
- Threaded method
- With the fixing screw
The Morse taper is one of the easiest and most practical methods that has been used since the 19th century. The plane of the shaft is machined in the form of a cone with the assigned parameters. A similar cone is located in the middle of the chuck. When they are combined, the components are quickly and firmly connected.
The following method is equipped with a thread that is cut into the edge of the power tool’s working shaft.
The fixing screw is used to additionally connect the screw-in chuck to the shaft. Typically, the screw has a Phillips head as well as a left-hand thread. It is necessary to unscrew the jaws of the chuck as much as possible in order to see it.
How to unscrew a chuck on a screwdriver
It has long been no secret that it is more convenient and fastest to unscrew and tighten screws with a screwdriver.
Any tool tends to wear out and fail. This is especially true for moving and frequently used parts. In a screwdriver, such a component is a chuck. An element that is completely out of order should be replaced. But first you need to understand how the cartridge is removed. To do this, you need to know a little about the technical characteristics of the device. To carry out repair work you will need a hammer, a screwdriver, a vise and some keys.
Chuck removal: Bosch screwdriver
Bosch screwdrivers are usually equipped with a locking screw.
- We put the key in the cams and tighten it for a couple of clicks.
- The tool is placed on the edge of the table.
- Pressing the stopper button, remove the chuck retainer on the shaft.
- The cartridge is removed against the clock movement.
All actions require special attention and sequence during disassembly / assembly.
Having received theoretical knowledge about the types of cartridges, it will be easier for you to independently repair the screwdriver Interskol, Hitachi, as well as other manufacturers.
How to change / insert / pull out an accessory (bit), drill
After the required nozzle (bit) for the drill has been selected, taking into account the size of the screw head and the configuration of the recesses (straight, cross), it must be installed in the very center between the open cams, and fixed in the chuck by turning the sleeve clockwise. If a key type chuck is selected, then the key is installed in a recess on the chuck, and then rotated hourly until the attachment is secured. The end of the bit fits into the groove in the screw. Before starting the device, check the accuracy of setting the direction of rotation, the direction must match the screw.
Increasing the pressure on the start button regulates the optimum rotation speed. When the screw is fully immersed, the force limiting mechanic is activated and then the drill stops.
The device and purpose of the power tool
The screwdriver is used for twisting and unscrewing various fasteners. The tool can be used for threading and drilling. It greatly facilitates and speeds up work. Screwdrivers are used in everyday life, construction, furniture assembly, car repair shops, wherever you need to work with a lot of fasteners.
The screwdriver can be cordless and mains
The main elements of the screwdriver:
- Cartridge.
- Torque adjustment clutch.
- Speed shifter.
- Motor in screwdriver housing.
- The gearbox is enclosed in the tool body.
- Reverse switch.
- Power button.
- The handle is rubberized to eliminate slipping.
- Battery.
- Power cord.
Screwdrivers are powered by batteries or mains.
Setting the torque
The drill has an adjusting ring for setting the torque, where its values are applied.
This is necessary for the ability to set a more suitable value when working with materials with different hardness.
Nettle, for screwing in drywall (with little effort) a range of values 2-4 is suitable, for hard wood the torque can be set to the highest number on the ring.
This adjustment helps to avoid quick damage to the fastener splines.
In due course of work, you can change the frequency of revolutions, increasing, in other words, lowering the pressure on the trigger of the tool.
This makes it possible to just stop the work of the tool when the screw is fully tightened, in other words, the screw.
How to change a nozzle on a screwdriver
Tool varieties: characteristic features
The screwdriver can be classified into the following varieties:
- Drill driver
- Wrench
- Cordless screwdriver
- Standard screwdriver
The drill-driver is able not only to tighten the screw, but also to drill a hole. The impact wrench is specialized in bolts and nuts. The third representative is a cordless screwdriver, designed exclusively for tightening / unscrewing fasteners with a cross head. The latter type is characterized by low power, in contrast to the above.
How to work in twist mode?
Before starting work, you need to prepare the tool. If it is running on battery, you need to put it on charge.
The next step is setting the bit. To choose the right nozzle, you need to take into account the size of the fastener head and the type of slot. Bits differ in type and diameter:
- slotted. Most often used. Designed for tightening countersunk head screws with a slot for a flat screwdriver, screws. Tip width varies.
- Cross. With their help, self-tapping screws, countersunk head screws are twisted and unscrewed. The tip has 4 radial diagonal ribs.
- Hexagonal. It is used for fasteners, the head of which has hexagonal recesses. Screws and screws of this type are used in the assembly of furniture and appliances.
- For bolts and nuts. A nozzle with a tip, inside of which a hexagonal recess is made. With it, the tool is used as a wrench, screws, screws, bolts are tightened.
There are other attachments, but they are less commonly used. How to change or even remove a bat? Having determined which bit is needed, insert it into the cartridge. The installation method depends on the type of cartridge. Insert into the quick-release attachment as follows: twist the chuck counterclockwise until the distance between the cams increases. Push the end of the nozzle between them, turn the cartridge clockwise so that the cams close and securely fix the part.
In a screwdriver equipped with a turnkey chuck, the process of changing the nozzle is more complicated. First, a key is inserted into a special hole on the device, rotated counterclockwise to loosen the clamp. Insert the bat, fix it by turning the key clockwise.
The next step is to test the functionality of the tool. If the screwdriver is powered from the mains, connect it to an outlet. Press the start button, check if the bit is scrolling. The rotation speed is adjusted using the same button, weakening or increasing the pressure. The tip of the bit is inserted into the recess on the head of the fastener, press the start button.
If you need to unscrew the self-tapping screw or screw, switch the reverse button.
What does a screwdriver consist of? Setting up the device.
In the plastic case there is an engine and a gear mechanism that drives the bit, which is installed at the end of the screwdriver. The device is provided with a start toggle switch, a direction and speed switch, a diode illumination and a puff time regulator.
The operating principle of the tool is very simple. The nozzle, previously fixed in the chuck, moves with the help of a shaft, which begins to move from the operation of the motor through a gearbox. Before using a screwdriver, you should find out if the battery is charged, and if the correct attachment is installed.
Immediately before doing the work, you need to look after such a nozzle so that it matches the head of a self-tapping screw or screw.
To install the desired nozzle, you should select it according to the size of the head of the fastener element and fix it in the magnetic holder of the chuck. First, the cartridge with the coupling must be removed from the device, and after fixing the bit, the cartridge must again be fixed to the screwdriver body.
Then you need to assign a suitable bit rate. The adjustment is carried out by means of a special regulator. The required mode is set in the off state of the instrument.
Before using the power tool, it is necessary to correct the screw-in depth of the fastening element. After some time, it may be necessary to replace the magnetic holder. To change it, the cartridge, magnetic mount and coupling are removed. Next, the cartridge with the coupling is fixed back into the screwdriver block housing.
Car charger
In search of a solution to the issue “is it possible to connect a screwdriver to the charger”, you can stop charging with a car AK-block. Modules with manually adjustable current, voltage are applicable. The connection is absolutely not complicated. it is enough to connect the input channels of the tool motor to the contacts of the car charger.
Other ways to supply power
A computer module will work too
Another solution to the problem of powering a screwdriver. mounting it to a computer power supply. This option is applicable to those modules that are equipped with a mechanical trigger. The positive aspect is that the unit is cooled by a cooler and is protected from exaggeration of the load by the built-in special system.
Such an assembly is arranged only with the use of power modules for 300-350 W and a current of 12 volts, at least 16 A. For instruments with a voltage of more than 14 volts, this power supply option does not work.
The user may want to hide an unaesthetic unit in a beautiful case, then it is recommended not to forget to arrange ventilation in it.
Is it possible to connect the screwdriver directly to the charger
The screwdriver is convenient for its ubiquity. independence from limiting wires makes it possible to wade into hard-to-reach areas. A set of two power modules allows you to power one of them while working with the other. However, each battery pack has a finite number of charge / discharge periods, failing when they are used up. In inexpensive tools, blocks break faster, and the user receives a gadget with a working motor, but no power. Then the dilemma arises “is it possible to connect the screwdriver directly to the charging”.
You can feed such a screwdriver by connecting it to the network through a power supply unit, because its motor operates at 220 volts.
Block inside
The solution to the problem “is it possible to connect a screwdriver through a charger” can be an alternative way to power the screwdriver. installing the power supply into the empty case of the power supply unit of the tool.
Before starting the action, it is necessary to prevent overheating of the unit, for which holes are arranged in the case in advance, which will provide air movement, heat removal. It is advisable to reduce the time of continuous work with a screwdriver with such an improvement to 15 minutes.
A ready-made block is purchased, it is selected according to the size of the case, technical indicators. The most suitable for use is the pulse version of the module, it is small in size, lightweight. The use of modules of domestic production from the times of the last century is not recommended. they have large volumes with low efficiency.
Unsuitable batteries are removed from the bed, and the power supply is placed in their place. The contacts are energized, the case is closed. The assembled hybrid gadget is ready to work from the network.
- Cables can be extended for convenience.
- It is necessary to monitor the quality of the assembly: the structure should not be able to touch the metal elements, otherwise the circuit cannot be avoided. It is best to leave some space between the transformer and the board, which will have a positive effect on cooling.
- If any parts of the structure are very hot, it is possible to install modules that remove excess heat, or to arrange ventilation slots.
On their own
For users with special knowledge and skills, there will be no difficult problem “is it possible to power a screwdriver from a charger without special means”, because assembly of the feeding block is possible with your own hands. Instead of damaged elements, a power module assembled according to the scheme is inserted into the case. Outgoing voltage is monitored, the wires are powered, the case is locked.
Tip: the circuit may require additional load, it can be ensured by including a 15W light bulb in the system, which will also provide backlight.
How to connect to the charging station
Before deciding whether it is possible to charge the battery of a screwdriver with a charger, you need to remember that the charging unit of the screwdriver supplies a low voltage, with a long wire length, the voltage is lost, so it would be rational to connect through a meter cord with a cross section of 2.5 mm2 or more.
- Wires are attached to the contacts of the charging unit of the screwdriver. Spoiled nutrients are removed from the nest.
- A groove is made in the case, a cable is passed through it. It is proposed to seal the entry point with elastic material so that there is no backlash and the wire is held securely in place.
- Since the nest has lost its weight after removing the unusable elements, it is recommended to restore the balance by inserting some kind of load into the vacated space, otherwise the hand will get very tired during work, eventually harming the health of joints and ligaments.
- The cable and previously attached wires are connected together, the body is assembled.
General recommendations
All of the above methods include one stage that combines them. disassembly of the housing of the power supply module. If the frame is fixed on bolts, then this is not a difficulty, fastening on the glue requires careful opening of the seam by tapping on the slot with a hammer, digging a knife into it.
During installation, observe the voltage direction. it should not be supplied to the battery. Therefore, the module is mounted in parallel with the power contacts, a diode illuminator for a certain power is built into the positive line.
Summary: there is a positive answer to the question “can a screwdriver work from a charger”, and there are several solutions, however, caution is required, some scientific knowledge and dexterity.
Use a drill
The bolt heads installed do not have the required geometric shape. In order to correct the situation, you can use a drill. With its help, we carefully trim the heads and legs of the bolts, giving them the necessary shape.
When working with a drill, it is important to perform short and smooth movements. Otherwise, the possibility of overheating of the plastic housing of the gearbox is not excluded, which will lead to its melting.
Unsolder the old switch
First you need to disconnect the old switch from the screwdriver body. A soldering iron is used for this. We must not forget about the need to fix the polarities on the sealed contacts of the old button.
How to repair a screwdriver gearbox
The tool reducer consists of a body in which its working elements are located. For instance:
- ring gear;
- Settelites;
- drove.
Depending on the manufacturer and model of the device, its internal elements can be made of metal or plastic. The first option ensures their long service life and tool reliability.
How to fix the button of the Interskol screwdriver
If the battery is charging normally, but the tool does not turn on, you need to check the state of the power button of the screwdriver.
To do this, after disassembling the device case, we get access to its button. At the terminals that go from the button, you need to measure the voltage level with a multimeter. In this case, the battery must be in an active state. If voltage is applied, the button contacts must be short-circuited using clamps. This switches the multimeter to Ohm mode. If the voltage is close to zero, it means that the button is in working condition. Otherwise, the button needs repair.
Solder a new switch
If you had to buy a new button, you need to pay attention to the fact that it must be completely identical to the old one, have the same dimensions and fit tightly into all grooves of the tool body. If there are small errors, you can correct them with a file and sandpaper.
Observing the polarity, solder the new button to the contacts of the electric motor. In order to make sure that all operations were performed correctly, experts recommend checking the button for turning on and the smoothness of rotation of the screwdriver. Only then can you start assembling the case.
Assemble the reducer
Before proceeding with the assembly of the gearbox, experts recommend checking the correct installation of new teeth. To do this, take a natfil and clean the surface of each erased tooth of the gearbox with it. If this is not done, the crown may not sit tightly in the groove of the body or it will scroll.
Then a metal crown is inserted into the body. If it does not scroll and sits tightly, then all operations were performed correctly and you can continue to assemble the gearbox. In this case, do not forget about the obligatory lubrication of all working elements of the gearbox.
Drill holes in the gear housing
First you need to take the smallest drill bit and drill 4 holes in the gearbox housing with it. It is important to pay attention to the fact that the holes should be located in the very center of the tooth.
Disassemble the gearbox
The housing of household models of the screwdriver is made of plastic, and of professional models. of alloy steel. After dismantling the metal plate, we get access to the inside of the gearbox: teeth and a gear change ring. If the crown has no defects, it is enough to clean it from dirt and lubricate it.
Hitachi DS 18DL Carbon Brush Replacement
Now it’s time to start examining the outer rim, the inner part of which is equipped with teeth along the perimeter. The efficiency of the gearbox depends on their condition. If the teeth are worn out, it is not possible to replace them with new ones. But there is a way out of the situation.
General information about batteries
Each screwdriver usually comes with two battery modules. The rechargeable battery for the interskol screwdriver consists of several batteries (batteries, “cans”). By their type, chemical composition, they can be nickel-cadmium or lithium-ion. Their number may be different, it depends on the voltage value, device model. All of them are collected together, connected in series. During operation, some of them may be depleted. such banks will need to be replaced.
Serviceable elements are purchased separately, making sure that their voltage and dimensions correspond to the old ones. Working batteries can be obtained by disassembling the second battery module, thus obtaining one of the two faulty blocks suitable for operation.
The battery pack consists of the following elements:
- two-piece plastic case;
- batteries connected according to a certain scheme;
- temperature sensor.
The thermal detector monitors the degree of heating of the batteries, and in case of overheating, it turns off the power until the device cools down to normal.
Self-replacement of batteries in the Interskol screwdriver
In the event of a screwdriver engine failure due to the depletion of some of its batteries located in the battery pack, it is possible to restore its performance. To do this, you need to know how to replace the batteries in the interskol screwdriver with serviceable ones.
Tips for disassembling battery packs
Before starting disassembly, the power supply unit is fully charged, after having cleaned its contacts with an emery sheet.
Parts of the battery module case can be fastened together in one of three ways, or a combination of them:
- bolts;
- glue;
- latch.
The latch opens quickly and easily, the bolts can be easily unscrewed, and force is required to open the glue line. In order for the case to be assembled later, it must be opened carefully. A hammer with a striker made of soft material (for example, rubber) is used to deliver gentle, precise blows to the seam. You do not need to beat hard, carefully, gradually breaking the integrity of the adhesive layer. The procedure should last long enough, more than 10 minutes, because multiple, fast-acting blows will split the plastic.
How to change batteries in an interskol screwdriver: process description
Among the removed batteries, you need to find those that are out of order in order to replace them. The search and identification of operable and unusable elements is carried out by measuring the stress of each of them separately and of the entire assembly as a whole. For lithium-ion batteries, the battery should deliver about 3.7 volts each when fully charged, and 10.8 volts when depleted. If the battery voltage exceeds these values, it is defective.
The detected faulty elements are disconnected: they are unsoldered from the electronic board, the metal plate is removed. The location of the poles is remembered.
New batteries must be soldered in place of the old ones, keeping the polarity (pros and cons). This is done with strict caution, quickly, avoiding overheating. An overheated element will quickly become unusable, there will be a danger of its explosion.
The structure is reassembled, the batteries are fixed on their sockets. All wires must remain intact, the temperature sensor is installed in its place, the case is neatly fastened.
If the battery of the screwdriver has lost its performance, it can be replaced. Used batteries for a Hitachi screwdriver can be replaced partially, or all.
To learn how to replace the battery in a Makita screwdriver, you need to familiarize yourself with the device. The battery pack of the screwdriver consists of: plastic.