How to repair the angle grinder with your own hands

How to repair angle grinder with your own hands quickly and easily

Along with the drill and electric screwdriver the place of honor in the garage is taken by the angle grinder, which can cut, saw, grind, polish and perform many other different actions by installing the appropriate attachments in the tool spindle. However, no matter how good the quality of the power tool, there still comes a time when there is a need to make repairs of the angle grinder with their own hands. In order to repair the device, you will need to understand its design and operating principle, which will allow you to independently identify malfunctions and eliminate them.

angle grinder or angle grinder is a special kind of electric tool, which is designed to facilitate the performance of work on cutting stone and metal, sawing wood materials, polishing and grinding surfaces, sharpening knives and various kinds of tools. This tool is quite worthy of the title of a universal tool, because with its help you can even drill holes, first fixing the chuck from the drill in the spindle, and installing the appropriate drill in it.

Why the angle grinder is popularly called “angle grinder”, not many craftsmen know, who have been using the tool for many years in a row. This name the angle grinder has received because back in Soviet times, the production of such types of power tools has been established in Bulgaria. To be more precise, angle grinders were produced in the city of Plovdiv at the factory “Eltos Angle Grinder”.

Many owners of angle grinders do not know all their functionality, and use them only for metal cutting or sharpening of cutting tools. However, the angle grinder can be used to do the following:

• Cutting of concrete, brick, reinforced concrete, cinder block, granite and other hard materials
• Cutting of metal parts of different thickness
• Cutting wood, plastic, drywall sheets and other similar materials
• Grinding and polishing of steel and stone materials
• Deburring of corrosion and rust from the surface of parts
• Sharpening of various hand tools and other products

All these activities can be performed by the angle grinder, provided the appropriate accessories are placed in the spindle, which are abrasive discs, cutting discs, sanders, grinding and polishing tips, emery discs, etc.п. The scope of application of the unit in question is only expanding every year, and it becomes possible due to the release of different attachments by manufacturers. And the possibilities of the unit are increased not only by manufacturers, but also by home craftsmen who build different devices from the device, for example, circular and sharpening machines.

With frequent use of the tool in question, various failures, defects and breakdowns occur. At one point it is still necessary to repair the angle grinder with their own hands, which is not difficult to produce at home. To independently repair the tool with your own hands at home, you will need some knowledge.

Mechanical malfunctions of the angle grinder

Angle grinder. it is an angle grinder, designed to perform cutting, grinding, polishing work. angle grinder in the course of work is exposed to high loads, works in a dusty environment.

Excessive loads when using the angle grinder in “Cutting” mode cause increased wear not only of the bearing, but also of the gear teeth.

The main malfunction of angle grinder on the mechanical part, wear or destruction of the sliding bearing on the shaft of a large helical gear reducer.

Troubleshooting an angle grinder is easy, if you have at hand its scheme, description and recommendations for repair work.

Friction bearing repair

The weak point of any angle grinder is the bearings. And although, they are few in design, only three, it is they that most often lead to mechanical failure. Bearings are negatively affected by:

• High rotational speed;
• Operating at excessive loads;
• Insufficient lubrication;
• ingress of dust or dirt;
• untimely replacement or destruction of carbon brushes.

Every angle grinder is designed for quick and easy replacement of any bearing.

Failure of angle grinder due to wear or destruction of plain bearing on gearbox shaft is indicated by appearance of unpleasant extraneous noise.

Failure of the plain bearing can be detected by checking the backlash of the implement shaft. Determined by rocking the shaft by installing the working tool.

When re-installing the power tool, check the clearance of the shaft by rocking the end of the shaft in all directions. There should be no or minimal play.

If play appears, the plain bearing must be replaced.

Repair of bearing consists in its removal from the housing and its removal from the gearbox shaft.

It is best to remove the bearing from the shaft with a puller. The inner ring of a destroyed bearing is best recovered by a drilling tap of the correct diameter previously screwed into the cage.

The bearings are removed from the rotor with a puller or by popular method.

Wrenches or strips of metal are inserted into the vise, the bearings are placed on the wrenches and with the help of soft metal and a hammer weighing at least 400 g are hammered out of the shaft axis.

Repair of angle grinder gearbox

The degree of wear of the angle grinder reduction gears is checked at the contact point. Beforehand, the gearbox is completely cleaned of old grease. A special blue coating is applied to the small gear wheel, the gear wheel is rotated. Next, you need to remove the large bevel pinion and look through a magnifying glass at the spot contact. It should occupy at least 50% of the tooth surface in total.

Otherwise the gears must be replaced or the tooth profile corrected. Correction of tooth profile is repeatedly described on the pages of this site.

But such a fault can only be repaired by an experienced craftsman. often than not, dented, sheared or broken gears are replaced as a whole and in pairs.

The main malfunctions of the angle grinder and their elimination

Before you repair the angle grinder, it is necessary to prepare the tools and materials that may be needed in the process of repair work:

• tester;
• screwdriver;
• wrenches;
• knife;
• tweezers;
• sandpaper;
• duct tape;
• solidol;
• alcohol;
• rags.

The main principle, which should be adhered to when repairing any power tool, is that you should move from simple to complex, that is, the sequence of repair work first should exclude elementary faults.

When the angle grinder fails, the first thing to remember is the circumstances under which the failure occurred. This will help with a high probability to establish the cause of failure, which will allow to make a successful repair of angle grinder.

The most common breakdowns of the angle grinder are breakage or short-circuited turns in the stator or armature windings.

The most vulnerable place of an angle grinder is the electrical part, which breakdowns occur most often. It can burn out from overloading the tool during work, from getting water inside the device, from power surges, etc.п.

The mechanical part does not like abnormal operating modes, poor or untimely maintenance of bearings and gearbox gear elements, tools falling on the floor. Therefore, before you repair the angle grinder, it is necessary to thoroughly clean its housing and starting mechanism. If this does not help, then the angle grinder will have to disassemble for further inspection and repair.

It is often the case that the angle grinder suddenly stops working. The first thing to do in this case is to disconnect the device from the power source and manually turn the disc. If it does not rotate or rotates very tightly, you must completely disassemble the tool and inspect its mechanics. If the disc is spinning easily, it means that there is no power to the motor brushes. This can be a consequence of a failure of the power cord or “Start” button.

The first thing to do is to inspect the power cord for continuity. Very often it is bent in the place of its entrance into the body of the angle grinder. To eliminate such a breakdown, you need to remove the cover from the handle of the device, and then use a tester to test the 2 wires. If you find a break in any place, it is better to replace the cable with a new one.

It is better not to make twists, because in a place of twisting the wire after a while will bend again.

With the handle cover open, you can immediately see the condition of the brushes on the armature collector. If they are worn out, they should be replaced. To do this, open the 2 brush holder windows and, by bending back the spring, carry out the replacement. New brushes should be similar to the old ones.

There can be soot deposits on the manifold plates that make it difficult for the brushes to apply pressure evenly. In this case the soot should be removed. To do this, take a pair of tweezers and wrap some absorbent cotton around it. Then take out the brushes, wipe them and the collector with alcohol, and then put the brushes back.

If after these operations the angle grinder still does not start, it means that the cause of the problem is in the starter button, which must be repaired. To repair, disassemble the trigger mechanism. It is advisable to mark the removable parts to avoid incorrect reassembly. Check the function of the button with a tester. If it is found to be defective, replace it with a new one.

Sometimes there is a situation where you hear an unusual noise when the angle grinder is working. To remedy the problem, open the gearbox and remove the 4 retaining screws. If the gear wheel is worn out, replace it with a new one.

If the tool has decreased RPM and you can see heavy sparking from under the brush, then the armature insulation is broken. It is necessary to dismantle the old anchor and replace it with a new one. Such repairs are not always cost-effective, because the anchor is quite expensive.

The bearings are another vulnerable part of the angle grinder. This is due to the fact that the tool often has to work in dust, and the high frequency of rotation implies that they wear out quickly. Wear of bearings is not the worst breakdown, because they are easy enough to change. The main thing is to replace them in time, because otherwise you may have more serious problems.

Mechanical breakdowns and troubleshooting

To the mechanical breakdowns of the angle grinder, you can include the following.

• Wear of the motor armature bearings. Usually when the bearings are worn, you can feel a lot of vibration when the machine is running. In addition, grinding and other noises can be heard. Sooner or later, the bearing will fail and the spilled balls will end up in the gears. If this happens, then in addition to the bearing, the gears will also have to be replaced. Of course, it is better not to wait for this unpleasantness and replace the bearing at the first sign of failure. How to get to this part of the angle grinder was described above.
• Wear of the ball bearing or the gearbox plain bearing. As in the previous case, when you turn on the machine will feel vibration and hear noise, not typical for normal operation of the angle grinder. To prevent further damage to the gearbox, it is necessary to replace the faulty part.
• Wear and tear on the gears. Gears wear out quickly due to insufficient lubrication. This is also the reason of gearbox heating. The lubricant level in the gearbox must be checked and changed if necessary. How to disassemble the gearbox was described above. Lubricant should be used specifically designed for gearboxes angle grinder, and you can buy it in the outlets where this tool is sold. If for any reason the teeth of at least one pinion are broken, then the whole set of gears (pair) must be replaced.

Mechanical faults include breakage of the shaft retainer. To replace the retainer, it is necessary to disassemble the gearbox and remove the big gear.

The main faults of the angle grinder and their causes

According to statistics, most cases of failure of the angle grinder are related to the electrical part of the machine. Some failures may be minor, which allows you to repair the angle grinder with your own hands. But, for example, if the motor windings burn out, the repair of the angle grinder can make only a specialist.

the angle grinder does not turn on

The reasons why the angle grinder does not turn on, may be the following:

• The electrical plug is faulty;
• The electric cable is defective;
• broke the start button;
• The contact between the power cord and the button is broken;
• Breakage of the contact wire of the electric brush;
• Heavy wear and tear on the brushes;
• Failure of the rotor or stator windings.

The angle grinder does not develop speed

The reasons for the fact that the angle grinder does not pick up speed, can be different.

• Failure of the adjustment unit. To check this version, connect the motor of the machine directly, without the regulator, and check the operation of the unit.
• Failure of the electric cable due to permanent kinks or mechanical damage. a damaged wire becomes warm under load and the engine speed starts to drop.
• Dust on the collector. Impurities must be removed with alcohol.
• Brush problems. They may be worn out or have a short contact wire as shown in the following photo.

Although the brush is half worn out, it is quite serviceable. In this case, the short contact wire does not allow the spring to press the electrode to the collector. This situation can also be the reason why the angle grinder does not operate normally.

The electric motor is heating up

Causes of the angle grinder overheating may include.

• Improper operation of the unit. Overloading can overheat the motor and often causes the windings to burn out.
• Destruction of bearings located on the armature. As a result, the rotor is caught in the stator, the motor is hampered and the windings overheat. The problem can be solved by replacing the bearings.
• Clogging of the ventilation ducts through which the air to cool the motor flows. The ventilation openings need to be cleared of dust.
• Breakage of the impeller, which is used to cool the motor. It is mounted on the rotor, on the opposite side to the manifold. If the impeller is broken, it must be replaced with a new one.
• Inter-turn short circuits of the stator and rotor windings. Rewinding of coils or replacement of such parts by new ones is required.

The angle grinder sparks

If you notice a strong spark when you turn on the angle grinder in the area where the collector is located, then the causes of this trouble may be.

• Armature winding damage: breakage of one or more winding sections, inter-twist short circuit. Such failures result in increased noise, reduced engine speed, and burned brushes.
• There is poor contact between the collector plates and the winding.
• Insufficient pressure on the brushes. In long angle grinder applications, the springs overheat and can “anneal” and lose their elasticity.
• Unbalanced motor rotor.
• Damage to the cylindrical surface of the collector. This sometimes occurs after rewinding if the armature is not turned on the lathe and immediately installed in the machine. In this case, you can also observe that the brushes are sparking excessively.
• There is a faulty insulation between the lamellae on the collector. There may also be graphite clogging of the track grooves or a breakdown between the lamellae.
• Bearing wear that causes rotor runout also causes brushes to spark harshly.
• Anchor shaft geometry malfunction. This usually occurs when the motor is not carefully disassembled, when the shaft is bent.
• Wrong brand of graphite brushes are installed. Brushes selected according to expected speed and voltage.
• Lifting one or more blades causes the brushes to burn out very quickly. This may be caused by motor overheating in continuous operation. The vitrified clay, which is the base of the collector, softens and the blades start to rise. Because the blades are up, the brushes wear out very quickly.

Angle grinder main malfunctions and troubleshooting

Before you repair the angle grinder, you need to prepare the tools and materials that you may need in the process of repair work:

• tester;
• screwdriver;
• wrenches;
• knife;
• tweezers;
• sandpaper;
• duct tape;
• solidol;
• alcohol;
• rags.

The main principle, which should be adhered to during the repair of any power tool, is that you should move from the simple to the complex, that is, the sequence of repair work first should exclude the elementary faults. When the angle grinder fails, the first thing to do is to remember the circumstances under which the breakdown occurred. This will help with a high probability to establish the cause of the breakdown, which will allow you to make a successful repair of the angle grinder. The most common breakdowns of the angle grinder are a breakage or short-circuited turns in the windings of the stator or armature. The most vulnerable place of the angle grinder is the electrical part, the breakdown of which occurs most often. It can be burned by overloading the tool while you are working, by water ingress, by power surges, etc.п. The mechanical part does not like abnormal modes of operation, poor or untimely maintenance of bearings and gearbox gear elements, the fall of the tool on the floor. Therefore, before you repair the angle grinder, you need to thoroughly clean its housing and starting mechanism. If this does not help, then the angle grinder will have to disassemble for further inspection and repair. Very often there is a situation when the angle grinder suddenly stops working. The first thing to do in this case should be to disconnect the device from the power source and manually turn the disc. If it does not rotate or rotates very tightly, it is necessary to completely disassemble the tool and inspect its mechanical part. If, on the other hand, it is easy to rotate the disk, the motor brushes are not receiving power. This can be caused by a broken power cord or start button. The first thing to do is to inspect the power cable for continuity. Very often it kinks in the place of its entry into the body of the angle grinder. To fix this breakdown, you need to remove the cover from the handle, and then use a tester to test the 2 wires. If there is a break in any part of the cable, it is best to replace it with a new one. Twisting is better not to do, because in a place of twisting the wire after some time again will bend. Design of the angle grinder armature. With the handle cover open, you can immediately see the condition of the brushes on the armature collector. If they are worn out, replace them. To do this, open the 2 brush holder windows and, by bending back the spring, replace. New brushes should be similar to the old ones. There may be soot deposits on the manifold plates that make it difficult for the brushes to press down evenly. In this case, the fouling must be removed. To do this, take a pair of tweezers and wrap some absorbent cotton around it. Then take out the brushes, wipe them and the collector with alcohol and then put the brushes back. If after these operations, the angle grinder still does not start, it means that the cause of the malfunction lies in the start button, which should be repaired. To repair, you need to disassemble the trigger mechanism. It is recommended that you mark the removable parts to prevent incorrect reassembly. Use a tester to check the function of the pushbutton. If it is found to be defective, replace it with a new one. Sometimes there is a situation when during the operation of the angle grinder is heard extraneous noise. To fix such a problem, you should open the gearbox, unscrewing the 4 fixing screws. If the gear is worn, replace it with a new one.

If the tool has reduced speed and you can see a strong spark from under the brush, it means that the insulation of the armature is broken. You have to dismantle the old armature and replace it with a new one. Such repairs are not always cost-effective, because the anchor is quite expensive. Another vulnerable place of the angle grinder is the bearings. This is due to the fact that the tool often has to work in dust, and their high frequency of rotation implies rapid wear and tear. Bearing wear is not the worst breakdown, because they are quite easy to change. The main thing is to replace them in time, because otherwise you may have more serious problems.

How to disassemble an angle grinder

Before the tool finally breaks down, you can observe :

• Strong vibration;
• Turn on the motor with a low hum;
• sparking of the collector brushes;
• smoke and odor coming from the housing;
• crackling inside the gearbox;
• Significant vibration of the housing when the work is done;
• bearings seizure.

Before you disassemble the angle grinder, you need to learn the rules that should be observed. The first is to unplug the tool from the mains. Perform work on a well-lit table. To keep the disassembly in an orderly fashion so that you know how to reassemble.

You can disassemble the angle grinder yourself, the main thing to remember the order of assembly

The tool is constructed of these parts:

The motor is the main drive point of the tool and the tool does not work without it. 2. At the expense of the gear unit is performed torque from the motor shaft to the spindle angle grinder. 3. The electric motor is energized and the contact closure process is carried out by the on/off button. 4.A spindle is needed to fasten the bits in the machine. 5.Use a power cord to connect the unit to the power outlet.

The main reason for breakdowns and situations when you need to make repairs angle grinder. it is improper use of the tool by craftsmen. There are two types of angle grinders by purpose:. for household work;. for regular work.

The category of household power tools is used only around the house without regular and prolonged use. Operate household angle grinders made of low-strength materials should not more than 10 minutes without stopping, then. let the motor cool down for 10 minutes. Few people monitor the operating time of the unit, so there are various damages in the angle grinder. Undoubtedly, any household angle grinder can be a reliable helper for a long time, provided they are used properly. Most often, experts advise not to repair the household angle grinder themselves, it is better to immediately contact a service center. Professional angle grinders, which are made of quality materials, are famous for the duration of operation of the device. Such devices are stable under long-term loads, work continuously up to 50 minutes and do not burn out.

In the case of breakdowns of bolt cutters, they can be divided into two types:

1.Repairable by your own hands, when oxidation or squeezing cords, contacts, electrical terminals. 2.Not to be repaired by your own hands are cases when you need to replace a part or mechanism in a special workshop, with special equipment. The angle grinder consists of the following parts: body (base), electrical part (armature and rotor ), mechanical part (gearbox, bearings, spindle, cooling cooler ).

It is not necessary to disassemble the angle grinder only if the power cable is broken. To repair the other components of the angle grinder you need to disassemble the two plastic parts of the housing to identify defects. A sign of failure of the angle grinder may be a situation when it does not turn on due to lack of power in the network, damage to the power cord, when it is possible that the contacts are suspended, the button failed or the brushes are worn out.

Often the place of premature wear and tear is near the inlet of the mains cord in the housing structure. When the button fails, the motor will not work, but the current to the device comes. In this case, it is worth replacing the button.

In a situation of operation of the device and its sharp sparking with a smell of burning, it is worth considering that the graphite brushes are out of order. They have a short lifespan and their contact quality decreases with wear. A crackling or ringing noise from the outside is a sign of aging bearings or gears. Bearings and brushes should be replaced every 6 months if the appliance is used continuously. Simple types of machine breakages are within the power of even a novice in the use of the machine, but in the case of a serious breakdown, you should not risk the tool if you are not confident in your abilities. Peculiarities of identifying and eliminating breakdowns of angle grinder at home

To carry out repairs with your own hands, you should first prepare the workplace and proceed to disassemble the unit. Depending on the company-manufacturer may vary the number of fasteners (at least 6 pieces). With a Phillips screwdriver, having disassembled the device, it is worthwhile to inspect and check the parts inside the tool. If you consider the nature of popular complaints, you can find these causes:

1.If it is impossible to start the tool. the cause of failure is in the electrical part. 2.In case of uncharacteristic sounds of the device operation. the cause of the breakdown is in the mechanical part. 3.If the housing is broken, it must be completely replaced.It is strictly forbidden to use a machine with a defective body for work.

Causes and stages of rewinding the stator of an angle grinder with your own hands. tips from professionals

The structure of electrified tools includes power units consisting of a stator, armature, brushes. They require repair in case of mechanical overload, prolonged work. Due to overheating of the wire, its insulation is broken, the turns are shorted. If there is no bandage, the winding ends are broken from the collector. To eliminate such problems it is recommended to wind 1000-2000 coils with the help of special devices.

Power surges, water intrusion, falling, and other phenomena cause the brushes to spark. In practice, more often there is a breakage of turns, which is associated with high overloads. Specialists believe that the electric motor fails because of the armature, a break in the magnetic circuit.

If the stator is disturbed, voltage rises, brushes spark. The latter process is due to improper balancing. When diagnosing at home, it is advisable to listen to the sound, taking into account the presence or absence of vibration. If the resonance is observed, the electric motor must be repaired with your own hands or with the help of specialists.

Anchor. a rotating element, which has a winding to create the necessary torque. It is transmitted to the motor gearbox. There are also wires on the stator, which consists of several parts. Current flows to the brushes and armature. This process is observed until all sectors of the power unit are engaged.

The stator differs from other parts of the motor in the number of revolutions, the cross-section. The main reasons for its repair:

If the circuit is operating normally, the armature rotates without stopping.

The gearbox is used to maintain the speed and the RPM. If it is out of order, it is disassembled. Slides the hood, opens the screw that fixes the plate. Since the gearbox is under the hood, it is necessary to unscrew the screws. The tool is plugged in. If the drive is accelerating at high speed, then a coil short circuit is observed. It is recommended to wind the wire from scratch.

It takes several hours to rewind the stator of an angle grinder. The device is cleaned of dirt beforehand. Old wiring is removed from the slots. A steel brush is used for this.

If there is damaged insulation it is also removed. To simplify and accelerate the cleaning of the insulation, the device is dipped into warm oil. The substance promotes the softening of the wire. The following tools are needed to carry out the repair work:

After deburring, the studs that hold the core are tightened. The washers are varnished and the grooves are insulated.

If the stator is burned out, the rest of the winding is cut off. The work is carried out so as to obtain the appropriate number of windings. The wire should have the diameter with the largest seal. Two coils are mounted in the stator. The leads are made from the winding. To insulate them, tubing is used.

If the wiring is not covered, inserts are fitted to protect it.

The coil is placed over the groove, which is at the bottom of the bore. Using a plate to install the coils. To prevent them from crossing, they are laid in a sequence similar to the winding on the template. The wires are placed strictly parallel. The stator body is mounted on a single compartment and the spacers in the grooves. The leads are fixed with twine. Its ends go parallel to the previous elements. The bottoms of the coils are installed in a similar way. The process continues until all the grooves in the step are filled.

If winding is complete, sleeving is performed. The parameters of the products depend on the dimensions of the stator. Highly heat-resistant film is wound onto special cardboard. The construction is fixed with adhesive tape. The coils with sleeves are mounted in the grooves.

If the armature moves freely, the unit is tied with bobbin tape, covered with varnish. The product is subjected to drying. At the last stage is the assembly of the angle grinder, followed by a test of its performance. In the absence of experience in the repair of power tools is recommended to seek help from professionals.