How to repair grinders do it yourself

Any power tool may fail over time. This is usually due to a violation of its rules of operation. Is no exception, and Bulgarian. If you have had such a trouble, you should not panic and immediately call the wizard, because in most cases you can fix the problem yourself.

Bulgarian device

Figure 1. The device of the grinder.

To do this, you need to know the basics of electrical engineering and a little to understand the design of grinding machines. Next will be considered how to carry out the repair of the grinder with his own hands.

Device and principle of operation of the grinder

To understand how the angle grinder works, you first need to become familiar with the principle of operation of this tool. With the help of electricity, the engine is operated, which transmits rotational motion to the shaft through a special gear. A grinding or cutting wheel is attached to its end.

The high quality of work carried out with the grinder will depend on the number of revolutions of the cutting blade per 1 minute. In professional power tools, this value can reach 10,000 rpm and more.


First of all, if the grinder breaks down, it should be disassembled and cleaned thoroughly, in most cases the tool starts working.

Different manufacturers may have slightly different layout of the grinder, but the main parts of all models are the same (Fig. 1):

  • housing designed in two parts;
  • electric motor of a certain power;
  • gearbox;
  • electric part.

The body is made of impact-resistant plastic. Its main task is to hold all the components in place and transfer the effort applied by the operator to the cutting element.

An electric motor drives the drive gear of the gearbox, rotating the driven gear, on the axis of which the disk is placed. The gearbox consists of gears, through which the axis of rotation is rotated 90 °. Thanks to the use of gears of different diameters, an optimum speed of rotation of the cutting blade is achieved.

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The main malfunctions of the grinder and their elimination

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

  • tester;
  • screwdriver;
  • spanners;
  • knife;
  • tweezers;
  • sandpaper;
  • insulating tape;
  • grease;
  • alcohol;
  • rags.

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

When an angle grinder breaks down, the first thing to do is to recall the circumstances under which the breakdown occurred. This will help with a high probability to establish the cause of the breakdown, which will allow for successful repair of the grinder.

Repair of the grinder

The most common damage of the grinder is a break or short-circuited coils in the stator or anchor windings.

The most vulnerable spot of the grinder is the electrical part, the failure of which occurs most often. It can burn out from excessive tool loading during the execution of work, from ingestion of water into the device, from power supply surges, etc.

The mechanical part does not like abnormal operation, poor or untimely care of the bearings and gear elements of the gearbox, the fall of the tool on the floor. Therefore, before you repair the grinder, you must thoroughly clean its body and trigger. If this does not help, then the grinder will have to disassemble for further inspection and repair.

Very often there is a situation when the Bulgarian suddenly stops working. The first thing to do in this case is to disconnect the device from the power source and manually turn the disk. If it does not turn or turns very tightly, then you need to completely disassemble the tool and inspect its mechanical part. If the disk scrolls easily, then this means that no power is supplied to the brushes of the electric motor. This may be due to the failure of the power cord or the Start button.

First you need to inspect the power cable for integrity. Very often, he bends in the place of his entrance into the body of the grinder. To eliminate such a breakdown, it is necessary to remove the cover from the handle of the device, after which the tester will ring out 2 wires. If a break is found in any place, it is better to replace the cable with a new one.

Twisting is better not to do, because at the point of twisting the wire will bend over again after a while.

The device anchors grinders

The device anchors grinders.

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

Soot can form on the collector plates, making it difficult to evenly press the brushes. In this case, the carbon should be removed. To do this, take a pair of tweezers and wrap cotton wool on it. After that, remove the brushes, wipe them and the collector with alcohol, and then set the brushes back.

If after these operations the grinder still does not start, it means that the cause of the malfunction lies in the start button, which should be repaired. For repair you need to disassemble the trigger. It is recommended to mark the elements to be removed, which will save you from improper reassembly. The serviceability of the button must be checked by the tester. If it turns out that it is faulty, replace it with a new one.

Sometimes there is a situation when, when the grinder is in operation, strange noise is heard. To eliminate this problem, open the gearbox by unscrewing the 4 fixing screws. If the gear has worn out, replace it with a new one.

If the tool turns are reduced and from under the brush you can see a strong sparking, it means that the insulation of the anchor is broken. It is necessary to dismantle the old anchor and replace it with a new one. Such repairs are not always cost-effective, since the anchor is quite expensive.

Another weak spot grinders - bearings. This is due to the fact that the tool often has to work in dust, and a high rotation frequency implies their rapid wear. Bearing wear is not the worst damage, because they change quite easily. The main thing is to replace them on time, otherwise you may have more serious problems.

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How to extend the life of the grinder

  • use the tool only for its intended purpose;
  • during operation, do not neglect the main technical characteristics of the grinding machine, as indicated by the manufacturer;
  • do not block the power tool;
  • carry out timely lubrication of the mechanical elements of the device, while using only high-quality lubricants;
  • carry out maintenance according to the technological cards on the equipment and to the full.

If you work with a grinder and you follow all the rules and recommendations, you can be sure that such a power tool will last much longer than its warranty period.

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