The famous Japanese brand Makita enjoys well-deserved popularity among consumers around the world. All Makita brand products stand out for their high quality, ergonomics, and affordable prices. And a competent Russian consumer tries to squeeze more out of the tool than it can give. Makita angle grinders have their own ultimate strength.

Do-it-yourself repair of the Makita angle grinder is not particularly difficult and can be done as in service center, and independently, since you can freely purchase the necessary spare parts. Malfunctions of the angle grinder and how to eliminate them are discussed in detail in the attached instructions.

Design features grinder Makita

Bulgarian is an angle grinder, which received such a name only in the expanses of the former USSR. Structurally, any angle grinder (angle grinder) has the same structure.

The principle of operation of Makita angle grinders is based on the conversion of electrical energy into mechanical energy. This leads to the rotation of the shaft, on which the disc for cutting, grinding, polishing is installed. And it is called angular for the reason that in the gearbox used, the torque is transmitted at an angle of 90º.

Since the cooling of the electric motor in the Makita angle grinders is provided by the suction of external air through the ventilation holes, the working parts of the Makita angle grinders are covered with a special protective powder varnish that prevents dust from settling. Structurally, Makita grinders are provided with a labyrinth system of seals and the Start button is sealed.

But each company introduces its own zest into the design to attract a buyer. The grinder Makita is not deprived of this either. Bulgarians Makita are conditionally divided into powerful and small.

Bulgarians Makita are marked depending on the power of the electric motor.

To design features Makita angle grinders include:

• The presence of a labyrinth device that protects the bearings from dirt and dust.
• The windings of the electric motor in the grinders of high power are protected by an armored coating.
• Makita angle grinders are equipped with a special system that protects the tool from jerking when starting, called the Super-Joint-System.

A few words about the SJS system. The system prevents kickback, eliminates jerks and jamming of the working body, protects the electric motor from overloads.

The system uses a spring, the purpose of which is to transfer forces from the rotor to the gears of the gearbox. The spring acts as a buffer, preventing jerks when starting and stopping. This design greatly reduces vibration and ensures smooth operation of the Makita angle grinder.

Makita Bulgarians are divided into classes according to the width of the working disk. Bulgarians are conditionally divided into three classes: light, medium, heavy. In turn, each class is divided into grinders for professionals and for domestic needs. Professional models of Makita angle grinders have an increased power reserve, an integrated security system, and an increased working life. Professional angle grinders perfectly withstand heavy loads for a long time.

Makita household angle grinders have high performance characteristics but very reasonable prices. For Makita grinders, a disc with a maximum diameter of 230 mm can be used.

Depending on the diameter of the disk, Makita angle grinders are divided into classes:

• The diameter of 115-125 mm characterizes the light class. Easily held with one hand by the body, which acts as a handle. But professional angle grinders of this class can be equipped with a rear handle, which has a built-in power button for the tool;
• A diameter of 150-180 mm refers the Makita grinder to the middle class. This category includes professional and amateur models equipped with electric motors of various capacities. Modern models have a swivel rear handle;
• The diameter of 230 mm characterizes the heavy class grinders. This class produces grinders Makita exclusively for professionals. These machines are designed to work on concrete, stones, bricks, etc. Their design incorporates all modern systems to protect the consumer from injury.

Makita grinder models are available for discs with diameters of 115 mm, 125 mm, 150 mm, 180 mm and 230 m.

In grinders of high power, it is possible to replace carbon brushes without removing the stator housing cover.

Makita Bulgarians of various capacities differ in appearance. Professional grinders with a power of over 1000 W have a large body and a comfortable rear handle. The handle is equipped with protective anti-vibration pads in black. Bulgarians with a power of up to 1000 W have a convenient body, which acts as a handle.

Makita angle grinders have a quick-release cover. This design allows you to quickly remove the protective cover.

Tool required for repair

Do-it-yourself repair of Makita angle grinders requires the use of a specific tool. Not without a set of screwdrivers. It is preferable that they be equipped with a ratchet mechanism. The best option use a cordless screwdriver. To repair the electrical part of the Bulgarian Makita, you will need a tester, a device for determining short-circuited turns IK-2. And also prepare an open-end wrench, bearing pullers, a hammer, a soft metal tip. Well, you can not do without the necessary lubricants , cleaning materials, liquids for washing off old grease.

It is necessary to start repairing an angle grinder with your own hands by preparing the workplace, installing the right lighting. You will need a diagram of the angle grinder of the desired model and the proposed instructions.

Any malfunctions of power tools are divided into two types: electrical and mechanical.

We will consider the repair of Makita grinder units using the Makita 9565 angle grinder circuit as an example.

Possible electrical faults

Makita grinder electrical malfunctions can be divided into control circuit malfunctions, rotor failure and stator failure.

How to troubleshoot the Makita grinder control circuits

If your Makita grinder does not turn on, the biggest cause may be a breakdown in the power and control circuits.

To get to the components of the control circuits, it is necessary to remove the rear cover of the housing pos.38 by unscrewing the self-tapping screw 4×18 pos.39. Switch ST115-40 K9565 poz.28 is mounted in the switch holder poz.27. The switch holder is closed with a cover poz.29, which is attached to the motor housing poz.33.

The power cable poz.37 is suitable for the switch. Using a tester, check the continuity of the circuits from the plug contact to the switch terminals. The switch poz.28 is controlled by the lever poz.30. From the switch contacts, check the circuit to the carbon brushes poz.42.

In control circuits, the weakest link is the carbon brushes. The angle grinder Makita 9565 uses carbon brushes CB-318 with auto-off, so check the brushes.

In professional angle grinders, speed controllers are installed. In grinders Makita with a power of more than 1000 W, the installation of a soft start system is provided. The Makita 9077SF angle grinder is equipped with such a system.

If the switch fails, the malfunction is eliminated by its complete replacement. If the power supply wire is broken or broken, the malfunction is eliminated by replacing the entire wire or removing its damaged parts.

The switching process is carried out using the lever poz.30. If you disassembled the grinder body for repair or maintenance, lubricate the lever movement grooves with silicone grease before reassembly.

Checking the electric motor

In addition to the control circuits, the electric circuit of the angle grinder includes a rotor and a stator. These are complex units, the repair of which is recommended to be carried out in specialized centers. But for Russian craftsmen there is nothing inaccessible. We recommend ours.

How to repair the stator grinder Makita

The failure of the stator, position 24, of the angle grinder is indicated by the appearance of a burning smell, overheating of the grinder body, and a spontaneous set of revolutions of the grinder. In the body of the angle grinder pos.33, the stator is fastened with four self-cutting screws 4 × 70 pos.21. To prevent damage, the stator is closed by protection poz.20.

Repair of the stator grinder Makita consists in determining a short circuit or open windings. It is best to perform stator diagnostics with a special device called IK-2. The stator is considered faulty if traces of darkening of the winding are visible, a break is detected or short circuit winding turns.

Just. We need to rewind its windings.

How to repair the rotor grinder Makita

In case of overheating of the grinder, the appearance of a burning smell, an increase in sparking in the area of ​​\u200b\u200bthe collector, it is necessary to pay attention to the integrity of the rotor pos.13.

Scheme grinder Makita

The dismantling of the rotor is associated with sequential disassembly. To remove the rotor, it must be released from the gearbox pos.3. To do this, unscrew the hex nut M6 pos.4. To unscrew the nut, you need to clamp the rotor with one hand. With the other hand, using an open-end wrench, unscrew the nut counterclockwise.

Remove the nut, pull out the flat washer pos.5, remove the spiral bevel gear pos.6, remove the retaining spring pos.7. Swinging the rotor to the sides, carefully pull it out of the gearbox housing pos.3. After removing the retaining ring pos.8, use a puller to pull the bearing pos.9.

The Makita 9565 grinder uses a 6001LLB bearing.

It remains to remove the flat washer pos.10 and the gearbox cover pos.11.

in front of you appearance grinder rotor Makita 9565 with an insulating washer pos.14, a flat washer 7 pos.15, a bearing pos.16 and a rubber boot 22 pos.17. In the angle grinder, a 627zz bearing is used on the collector side. Russian analogue 80027.

Rotor repair consists in replacing it with a new or repaired one. You can repair the rotor yourself, but you need not only patience, equipment, material. This is a high class job.

Mechanical damage

In addition to the electrical part, the grinder also includes a mechanical part, the main unit of which is the gearbox.

How to repair the grinder gearbox

The gearbox consists of a housing, driving and driven gears. The drive gear is put on the rotor shaft. The driven gear is attached to the spindle poz.50.

On the grinder Makita 9565, the driven gear is pressed onto the spindle. And in the grinder model Makita 9558HN, the driven gear is mounted on the shaft with a keyway.

Reducer failures are associated with the failure of the gear teeth. Gears are licked or some of the teeth are chipped.

Repair gearbox grinder Makita is to replace a pair of helical gears. Gears are replaced only in pairs.

To remove the driven gear, you can not do without a press or a special puller. Do not use a hammer as the gearbox housing is made of fragile material.

Assembling grinder Makita 9565

Before assembling the Makita grinder, check the integrity of all parts and their cleanliness. The assembly begins with the installation of the bearing and the driven gear on the spindle.

Spindle Assembly

Anther poz.51 is put on the spindle poz.50, the housing cover poz.53, the bearing housing poz.54. Insert a pre-lubricated 6201LLB bearing into the bearing housing. Press the driven gear poz.56. on the spindle. Spindle assembled.

Installing the rotor in the gearbox housing

Insert a repaired or new rotor with bearings on into the gearbox housing, put on all the parts according to the drawing, fit the drive gear and fix it with a nut.

In the process of installing the rotor in the gearbox housing, control the pressing of the bearing. A properly installed rotor turns easily in the gearbox housing.

Installation of the rotor in the stator housing

An assembled gearbox with a rotor is inserted into the stator housing, on which the bearing is pressed from the side of the collector, closed with a protective rubber boot, and the ease of scrolling is checked. It remains to install the assembled spindle in the gearbox housing.

Insert the assembled spindle into the gearbox housing pos.3, after laying the rubber ring pos.55 and lubricating the bolts pos.52 with sealant.
Service Makita GA 5030 \ Repair Makita 5030

Video: Maintenance of Makita GA 5030 \ Repair of Makita 5030 \ Repair of power tools \ maintenance tool

All operations for assembling the mechanical part of the grinder are accompanied by mandatory parts. Pay special attention to the process of applying lubricant to the grinder gearbox.

Here it is important not only its quality, but also quantity. Lubrication in the amount of 1/3 of the volume of the gearbox is placed in the gearbox housing of the angle grinder.

Having assembled the mechanical part of the grinder, each time before tightening the fixing screws, check the ease of rotation of the gearbox by turning it by the spindle.

At the final stage, it remains to install the carbon brushes, put on the back cover of the case and check the tool's performance.

Makita 9565 grinders are equipped with CB-325 carbon brushes. Timely replacement of carbon brushes will not only save the rotor, but also extend the life of the entire tool.

As a rule, carbon brushes are changed after 7000 hours of operation or when worn up to 8 mm in length. In ec strange cases can be used. But at the first opportunity it is necessary to establish relatives.

If your grinder after assembly works without extraneous noise, without jerks, you can be congratulated. The task of repairing the grinder Makita has been completed.

(UShM), in the common people of Bulgarians, have a speed controller.

The speed controller is located on the angle grinder body

Consideration of various adjustments should begin with an analysis of the electrical circuit of the angle grinder.

the simplest representation of the electrical circuit of a grinder

More advanced models automatically maintain the rotation speed regardless of the load, but tools from a manual disk are more common. If a trigger-type regulator is used on a drill or an electric screwdriver, then such a regulation principle is not possible on an angle grinder. Firstly, the features of the tool suggest a different grip when working. Secondly, adjustment during operation is unacceptable, therefore, the speed value is set with the engine turned off.

Why regulate the speed of rotation of the grinder disk at all?

1. When cutting metal of different thicknesses, the quality of work is highly dependent on the speed of rotation of the disk.
   When cutting hard and thick material, it is necessary to maintain the maximum rotation speed. When processing thin sheet metal or soft metal (for example, aluminum), high speeds will lead to edge melting or rapid blurring of the working surface of the disc;
2. Cutting and cutting stone and tiles at high speed can be dangerous.
   In addition, a disc that spins at high speed knocks out small pieces from the material, making the cut surface chipped. And for different types stones are selected at different speeds. Some minerals are just processed at high speeds;
3. Grinding and polishing is basically impossible without speed control.
   By setting the speed incorrectly, you can spoil the surface, especially if it is paintwork on a car or material with a low melting point;
4. The use of discs of different diameters automatically implies the mandatory presence of a regulator.
   Changing the disk Ø115 mm to Ø230 mm, the rotation speed must be reduced by almost half. And it’s almost impossible to hold in your hands with a 230 mm disk rotating at a speed of 10,000 rpm;
5. Polishing of stone and concrete surfaces, depending on the type of crowns used, is carried out at different speeds. Moreover, when the rotation speed decreases, the torque should not decrease;
6. When using diamond discs, it is necessary to reduce the number of revolutions, since their surface quickly fails due to overheating.
   Of course, if your angle grinder only works as a cutter for pipes, angles and profiles, a speed controller is not required. And with the universal and versatile use of angle grinders, it is vital.

To date, the stores have a very large selection of power tools. All of them differ both in price and in functionality and reliability. Almost all modern models of electric drills, jigsaws, screwdrivers have a speed control. But grinders with such an opportunity are very rare, and if they exist, they are much more expensive. In order not to overpay too much, I decided to equip my grinder bought long ago. In principle, a regulator is not needed for cutting metal with a cutting stone, but for grinding cases in amateur radio practice, it simply cannot be replaced.

Schematic diagram of the grinder speed controller

So, the controller circuit. It is very simple, and there is a topic on our forum to discuss it. Even for a beginner radio amateur, it will not be difficult to assemble it. Parts are not expensive, and you can easily buy them in a store, or solder them from old boards (if they are there, of course). Can also be assembled separately in a box with a socket. Then use it as a carrier with a power regulator. For a while I was like that. After I got tired of competing with carriers, and I assembled the regulator in the handle of the grinder.

First you need to collect all the details in a bunch. Unscrew the handle of the grinder, and consider the location of each element of the circuit. Different brands of grinders have different handles, and how you place everything there, and indeed, whether everything will fit in there is already your concern. In extreme cases, you can collect in a separate box.

Radiator cut from a piece of aluminum. A triac was attached to it. By the way, it does not get very hot during operation, so the radiator can be made with a small area. Then I soldered all the parts by surface mounting according to the diagram.

So that during operation this whole thing does not shake and short-circuit - it is glued with epoxy. Variable resistor installed on the other side. He put on a large plastic handle. Even when working with it, it is convenient to change the speed of the grinding wheel.

Do-it-yourself repair of an angle grinder should be done with great care and without haste. The negative consequences of manipulations with the power and / or electronic unit can lead to the transformation of a minor breakdown into a complete rejection of the grinder, and then even a professional master will not save it.

Bulgarian - rules for working with electric grinding tools

An angle grinder is called a "grinder" only in the repair expanses of the former USSR for a prosaic reason - the Eltos-Bulgarian plant in Plovdiv was solely engaged in its production. The high-speed cutting wheel is an indispensable assistant in the processing of the most durable metal, in the arrangement siding on the ceiling, when cutting reinforcement, sheets, profiles and many other repair operations. The grinding capabilities of grinders are no less popular - they allow you to eliminate burrs, roughness from both metal and stone or marble.

Over the past 40 years, the range of angle grinders has grown tremendously, but the rules for handling this convenient and multifunctional tool didn't change much. Furthermore - repairs are often prevented by following simple operational guidelines:

• Do not remove the guard over the abrasive wheel unless absolutely necessary. If this cannot be avoided, be sure to work in goggles and protect the tool from any side contact;
• Do not process wood, chipboard, MDF and similar materials - saws and hacksaws are available for this;
• Hold the grinder firmly and confidently - when the disc is jammed, the entire tool can be pulled out of your hands, it will be severely damaged and cause serious injury;
• The work of any angle grinder is accompanied by the presence of characteristic sparks - beware of getting them on the electrical wiring, power cord and any other combustible materials;
• Any workpiece - cut or grinded - must be securely fastened. Even if it is necessary to cut a reinforcing bar immured in concrete during construction strip foundation from corrugated board, you should make sure that the entire structure is strong before pressing the "Start" button on the grinder;
• Do not press on the part to speed up the work. The principle of operation of abrasive wheels is to erase the material of the workpieces and does not need a large clamping force.. The accuracy of movements when working with a grinder is as useful as brute force is harmful.

Tool repair - rely on knowledge of its design and common sense

Any angle grinder consists of the following components and mechanisms, the location and condition of which should be confidently understood:

• Anchor. The internal part of an electric motor that rotates when the tool is operated at a controlled angular speed. The higher the rotation speed of the armature, the greater the power of the grinder. Unlike the marine "brother", the anchor in the electrical equipment should not slow down under any circumstances;
• The collector is a separate place (platform) at anchor, where the power and control windings are brought out. Already from the name it is clear - here the switching of signals to the engine and the control unit takes place. The collector is clearly visible after removing the case - the contact plates are polished and have significant dimensions;
• Electric brushes - special variety conductors for supplying current from the power cable to the collector. In working condition, they sparkle weakly and evenly, their glow is visible through the ventilation holes in the grinder body;
• The gearbox is a special mechanical device at the front of the grinder. Designed for transmission mechanical energy rotating armature to a rotating disk. In this case, both the speed of rotation of the working disk and the power developed by it are subject to adjustment;
• The stator is the part of the electric motor of the angle grinder in which the armature (rotor) rotates. The most difficult part of the tool, due to the strict precision of the windings pressed into it. Rewinding the stator of a grinder with your own hands is an adventurous procedure, it is better to entrust it to a specialized workshop;
• Handles-holders, power cable with a plug and a housing with control and regulation devices.

An extremely desirable assistant in the repair will be layout and electrical circuits, as well as detailed instructions specifically for the model of the angle grinder that needs to be repaired. Unfortunately, many manufacturers do not burden their devices with such excesses. In this case, you can get the necessary information from the know-it-all Internet and not repair the grinder with your own hands, counting on “maybe everything is simple there”, of course, if you don’t want to buy a new tool based on the results of the repair procedures ...

Do-it-yourself grinder repair - we eliminate typical malfunctions

The main principle in the repair of any electrical equipment is the postulate "move from simple to complex."

Whether it's a household electric cartridge or a turbine at a hydroelectric power plant, the repair sequence should exclude elementary faults in the first place. Electricity and electronics are called the "two sciences of contacts" for a reason. Typical malfunctions of angle grinders, coupled with methods for their elimination, are as follows:

• The tool suddenly stopped showing signs of life. With a probability of 90%, we can conclude that the current from the socket does not reach the electric brushes. That is, the problem lies either in the power plug, or in the wire itself, or in the Start button mechanism. It is enough to disassemble the case and “ring” the cable with an ordinary tester for breaks - very often it is enough to replace the wire, and the angle grinder will work like new;
• Are the wire and plug guaranteed to be intact, and the tool is still immobilized? It is necessary to disassemble the trigger, and it is desirable to mark the contacts to be removed - if they are subsequently connected incorrectly, the winding may burn out or the armature may jam. You can replace the start button with any similar one, the operating parameters are marked on it quite legibly;
• The "Start" button and the power wire are in working condition, but the grinder does not want to work? It's time to work on the holders. Very often, it is enough to clean the contact plates on the collector, and a long-awaited spark and a smooth buzz of the mechanism appear. If not, then the brushes need to be replaced. The resource of these devices is usually limited to several years. A number of models of angle grinders are produced with a soldered connection of electric brushes, you need to solder and install new ones in the kit, their partial replacement is not allowed;
• After replacing, carefully inspect the old electric brushes - if they have uneven wear, this is a clear sign of a shift in the center of gravity of the tool or its moving inside. It is better to contact a specialized company for the repair of complex electrical equipment - it is unlikely that you will be able to adjust the balance yourself without experience.

Brush replacement refers to the "top of the first level" in self-correction of faults in electric grinders. You can continue to paint repair recommendations, how to disassemble the grinder gearbox, rewind its winding or reconfigure the electronic filling. But serious breakdowns require a serious approach to work. If you have never seen this gearbox, how will you be able to fix it? The chance of turning on the grinder depends on your common sense - saving on professional repairs will result in the loss of the entire tool.

For everyone who has been using the grinder for more than one year, it broke. At first, each master tried to repair the sparkling grinder on his own, hoping that it would work after replacing the brushes. Usually, after such an attempt, a broken tool remains lying on a shelf with burned-out windings. And a new grinder is bought to replace it.

Drills, screwdrivers, rotary hammers, milling cutters are necessarily equipped with a speed dial regulator. Some so-called calibration grinders are also equipped with a regulator, and ordinary grinders have only a power button.

Manufacturers do not deliberately complicate low-power angle grinders with additional circuits, because such a power tool should be cheap. It is clear, of course, that the service life of an inexpensive tool is always shorter than that of a more expensive professional one.

The simplest grinder can be upgraded, so that the gearbox will no longer be damaged and winding wires anchors. These troubles mainly occur during a sharp, in other words, shock start of the grinder.

All modernization is just assembly electronic circuit and fix it in the box. In a separate box, because there is very little space in the handle of the grinder.

A tested, working circuit is laid out below. It was originally intended to adjust the incandescence of lamps, that is, to work on an active load. Her main asset? simplicity.

1. The highlight of the soft starter, the schematic diagram of which you see, is the K1182PM1R chip. This microcircuit is highly specialized, of domestic production.
2. The acceleration time can be increased by choosing a larger capacitor C3. While this capacitor is being charged, the electric motor speeds up to maximum.
3. No need to replace the resistor R1 variable resistance. The 68 kΩ resistor is optimally matched for this circuit. With this setting, you can smoothly start the grinder with a power of 600 to 1500 watts.
4. If you are going to assemble a power regulator, then you need to replace the resistor R1 with a variable resistance. A resistance of 100 kΩ or more does not lower the output voltage. By short-circuiting the legs of the microcircuit, you can completely turn off the connected angle grinder.
5. By inserting a TS-122-25 semistor VS1 into the power circuit, that is, at 25A, you can smoothly start almost any grinder available for sale, with power from 600 to 2700 watts. And there is a large margin of power in case the grinder jams. To connect grinders with a power of up to 1500 W, imported seven-stores BT139, BT140 are enough. These are less powerful electronic keys cheaper.

The triac in the above circuit does not fully open, it cuts off about 15V of the mains voltage. Such a voltage drop does not affect the work of the grinder. But when the sevenstor is heated, the speed of the connected tool is greatly reduced. This problem is solved by installing a radiator.

This simple circuit has another drawback - its incompatibility with the speed controller installed in the tool.

The assembled circuit must be hidden in plastic boxes. The housing made of insulating material is important, because you need to protect yourself from mains voltage. You can buy a junction box at an electrical supply store.

A socket is screwed to the box and a cable with a plug is connected, which makes this design look like an extension cord.

If experience allows and there is a desire, you can assemble a more complex soft start circuit. Below circuit diagram is standard on the XS-12 module. This module is installed in the power tool at the factory.

If you need to change the speed of the connected electric motor, then the circuit becomes more complicated: a tuning resistor of 100 kOhm is installed, and a control resistor of 50 kOhm is installed. Or you can simply and roughly introduce a 470 kΩ variable between a 47 kΩ resistor and a diode.

In parallel with the capacitor C2, it is desirable to connect a resistor with a resistance of 1 MΩ (it is not shown in the diagram below).

The supply voltage of the LM358 chip is in the range from 5 to 35V. The voltage in the power circuit does not exceed 25V. Therefore, you can do without an additional zener diode DZ.

Whatever soft starter you build, never turn on the tool connected to it under load. Any soft start can be burned if you rush. Wait for the grinder to unwind, and then work.

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