Metal brushes for grinders amaze the imagination with their variety. Their main purpose is to clean metal from old paint, from corrosion. True, there are also hand brushes with wire bristles for small amounts of work.

What kind of instrument is a grinder?

Bulgarian or corner Grinder– a universal and necessary tool in the household. This tool is used by painters, mechanics, and is in the arsenal of carpenters. Its significance varies depending on the attachments used. Put a circular disk on the machine and you can cut wood. More often, a grinder is used in metalworking for cutting metal: pipes, fittings.

But its main purpose remains grinding work. With the increase in secondary sales of cars, the demand for their repair and painting increases. The most difficult stage in this work is the preparatory stage, that is, cleaning the surfaces of cars from old paint and primer. The cleaner the body is before new priming, the better it will hold up. new paint. In this work, the leading role is played by a grinder with a set of sanding brushes.

What types of brushes are there?

Metal, cup-shaped brushes appeared relatively recently. Before this, sanders worked primarily with sandpaper. different types or emery stone discs. The paper, no matter how high their rigidity, quickly became clogged with paint particles or erased. It often had to be changed, which reduced productivity. Working with a metal brush for an angle grinder is much more effective in this regard.

Almost every leading tool manufacturer has considered it necessary to throw their brushes onto the market. And each manufacturer has its own approach, its own exclusive approach to the development and manufacture of metal attachments for angle grinders. Some brushes are made from a single thin wire, others from twisted cable, and others from wavy corrugated wire. Wire cord brushes differ in diameter, stiffness, and quality of bristles. Brushes used as attachments for angle grinders are:

1. Cup
2. Disk

Metal brushes are made from:

• become;
• steel with brass coating;
• brass;
• copper

There are polishing brushes for working on metal surfaces and woodworking. They are made from nylon and other polymers, dried seaweed, cotton fibers.

The rigidity of processing depends on the structure of the wire, its hardness and thickness. The thinner the wire used in the manufacture of the brush, the softer it acts on the metal. To clean the surface from old paint job on initial stage It is better to use a nozzle with stiff bristles, and for final cleaning of primer residues and other materials will suit a nozzle with less rigidity that will not “eat” the bare metal.

The wire used to make brushes is:

• Corrugated. Due to its springy properties, this brush softens, on the one hand, the impact on the metal, and on the other, reduces the vibration of the machine.
• Twisted. The bristles twisted together provide rigidity to the surface and are less likely to break and fly out when abraded. The twisted fragments unwind, freeing the bristles for work.
• Smooth.

Brushes differ in the diameter of the cup, which determines the parameters of the surface being processed simultaneously. Angle grinder brushes are consumables, but manufacturers are concerned with making them as efficient as possible and extending their service life.

What is the correct name for them?

There are discrepancies in the names of the attachments online and on labels. Some call them grinder brushes, others call them cord brushes. What should they really be called? Cord is translated from English as string, cord, rope. And if you look closely, these attachments are made from a variety of steel (or nylon), cut into short bristles, strings or twisted cords. So the essence of this name – cord brush – becomes quite clear. Those who write korshchetka obviously took the name of the nozzle by ear, and since the letter “d” is most often swallowed when pronounced, they began to write it that way. Do not know how spelling dictionaries, but the Word program in which this article is written recognized the correct spelling as cord-brush - with a hyphen.

Brushing as a process of working with a brush

Brushing is the name given to the process of treating metal surfaces. metal brushes for the purpose of removing loose sludge or scale formed during the etching process. This work can be done by hand or with power tools. The brushes themselves for angle grinders are called brushes. With this treatment, the porosity of the galvanic deposit decreases and it becomes denser. The treated surface is more uniform.

Brushing of steel surfaces is carried out with steel brushes with a wire diameter of 0.2–0.4 mm. Non-ferrous metals are processed with wire brushes made of copper or brass. Electroplating is also subjected to brushing in order to increase the density of the coating and give it shine.

Brushing is done according to:

• dry surface;
• surface wetted with water, soap or soda solution.

When brushing with metal brushes, abrasive pastes are not used, since the ends of the wire bristles serve as the abrasive.

How to choose a quality brush?

When choosing a brush for an angle grinder, pay attention to the bristles. It should be distributed evenly over the entire disc, the bristles should be the same length everywhere and distributed evenly around the entire circumference of the cup. It is unacceptable when the bristles are thick on one edge and thin on the other. Such a brush will hit your hand (vibrate), cleaning will be done unevenly, and the brush itself will very soon fail.

Among the parameters for the wire nozzle, manufacturers indicate the recommended speed for the machine. This indicator should not be ignored. If you put a low-speed brush on a machine with a high rotation speed, it will not give the desired result and will quickly fail. Conversely, a metal brush, which the manufacturer designed for use at high speeds, will not work with proper performance at low speeds.

The smaller the diameter of the cup, the less load on the machine engine, the less vibration, and, accordingly, the less tired the hand. But the larger the diameter of the cup, the fewer passes there are. Which brush should you choose? There is no clear answer here. Sometimes masters have time to try several brushes different diameters and different bristle stiffnesses before they find best option. The choice of brush often depends on the quality paint coating. After all, as you know, different enamels and primers have different coating densities.

The creative thinking of our people knows no bounds. This recommendation, aimed at improving the performance of brushes, was found on the forums of craftsmen.

Everyone knows that the bristles of a sanding attachment wear out over time, and this rate of abrasion depends on the stiffness of the bristles and the aggressiveness of the surface being treated. In some brushes, the outer cup is larger than the inner one, which allows you to extend the life of the brush a little, by 15 percent. This can be achieved by cutting off the upper edge of the outer cup of the brush by 5–7 mm.

Safety precautions

When processing surfaces, whether metal or wood, safety precautions must be observed. The fact is that the higher the rotation speed of the disc on the grinder, the faster the brush wears out. Metal bristles fly off from it, grains of scale and metal burrs also fly off from the surface being treated. It happens that the cup cannot withstand the load, and the brush itself falls apart.

And all this literally hits the working person. Therefore, when working with such a brush, you need to have glasses, a respirator, mittens and preferably thick overalls. Even if the sun is shining outside and the heat is unbearable.

The loud sound of the grinder tires and makes the worker irritable, so it is also recommended to have headphones. Some workers combine business with pleasure and drown out the sound of their grinder with their favorite music, inserting headphones from a player or phone into their ears.

Previously, angle grinders for Soviet Union were produced in Bulgaria, hence the common name of the instrument. The USSR has not existed for many years, but such devices, no matter who produced them, continue to bear this name among users. Like any technically complex product, this tool sooner or later begins to need repair, which most often consists of replacing the grinder brushes.

To understand the operation of the mechanism and why breakdowns are possible, you need to have an idea, at least schematically, of the main components of the tool.

Regardless of model, manufacturer and technical characteristics, any grinder has the following details:

• The moving part of an electric motor is called an armature, or, what would be technically correct, a rotor. As a rule, this element is combined with a working shaft that transmits torque.
• Contacts of the collector, which is a switching board, through which the voltage is removed from the current collectors.
• Brushes pressed against it provide electrical contact. When pressed lightly, they begin to spark strongly.
• The internal stationary winding is the stator. The rotation of the armature in it is achieved due to electromagnetic induction.
• Mechanical reduction gearbox for speed regulation.
• Other components: housing, usually plastic, handles, start button, power cable.

As a working tool, an angle grinder is subjected to high loads and increased continuous operation time. Despite the maximum tightness, dust, small fragments of processed materials, and scale periodically get inside the housing. This negatively affects both the mechanical parts and the electrical part.

As a result, the conductive parts become contaminated and the collector lamellas gradually burn out due to overheating. In turn, this leads to destruction of the current collecting brushes, which will be signaled by increased sparking.

Since contamination of the grinder is inevitable, you need to know more about the design of this part. For various malfunctions, the largest percentage is detected in this node. Moreover, even in working instrument unforced wear of the brushes is inevitable, although this happens very rarely.

Selection of electric brushes

This the element is a hexagonal geometric figure with identical parallel edges. To ensure electrical contact, a copper lead is pressed into it.

The sizes and shapes of brushes vary, as does the material used to make them. The initial device was simple: copper wire and a conductive brush. But due to great wear and tear, this design had to be modernized.

Modern current collecting elements are produced by compressing carbon materials with increasing temperature and pressure.

If, when working with an angle grinder, as well as a drill, the tool functions jerkily, with a characteristic burning smell, then the root cause lies in the wear of this small part. It is not recommended to neglect their replacement, as this will inevitably lead to failure of the device. In this case, you need to stop work, find out the reason why the brushes on the electric motor are burning, and begin repairs.

Underestimating the importance of the good condition of this part leads to serious consequences. Timely measures to prevent them will extend the service life of the tool.

First you need to understand the types of current collectors:

Before purchasing a replacement set of brushes, you need to find out their type and size in technical passport tool.

The grinder, like most power tools, was originally designed to operate from a power source direct current. Then, by connecting the rotor and stator windings in series, it became possible to be powered by alternating current without limiting the speed, as happens with brushless motors. Therefore, increased requirements are placed on the unit with the current-receiving mechanism. AND If the brushes on an angle grinder burn, the reason may be as follows:

• Malfunction of the rotor winding: turn short circuit, broken coils. A characteristic feature This is caused by a decrease in the number of revolutions and a loud hum.
• An equivalent reason is poor contact between the lamellas and the winding.
• The springs of the brush holder mechanism have weakened.
• Armature runout due to destruction of bearings.
• Reservoir development.
• The paths between the lamellas are clogged with graphite dust or they have shorted out. They can be cleaned with a metal saw blade.
• Deformation of the rotor shaft.
• As a result of rewinding the armature, the current-carrying coils are mixed up.
• The wrong brand of brushes was selected.
• Natural wear of the current collector.

Not every one of these reasons causes brushes to wear out quickly, but none of them can be ruled out.

Replacement methods

Once it has been established why the brushes on the angle grinder are burning and the cause of this malfunction has been eliminated, you can begin to replace them. There are two options for the process itself:

Prevention of collector devices

In order to extend the service life of the anchor, and accordingly the electric tool, it is necessary to perform several simple rules. These measures are as follows:

• Do not allow the device to operate for a long time at low speeds under a significant load, and especially not to allow the cutting part to bite. When an electric motor jams, a short blocking time is enough for it to burn out.
• If the device is jammed, it must be carefully released and allowed to work for free. idle speed two minutes. During this time, due to natural cooling, the heated parts will cool down a little.
• Observe the timing of adding or replacing lubricants.
• If vibration or noise occurs, it is necessary to carry out a preventive inspection by disassembling the housing and cleaning both the collector and the entire space inside from dirt.

If you replace inexpensive parts in time, you can avoid the cost of major repairs.

Any independent work for repairs of power tools, not only angle grinders, it is recommended not to carry out repairs until completion warranty period. Manufacturers do not welcome unauthorized intervention into the equipment. This does not apply only to replacing brushes without opening the case, but in other cases it is better to seek help from an authorized service center.

An angle grinder, if you know and correctly use all its capabilities, is a truly universal device that can be used on almost any material. And if we're talking about about processing wood on a large scale, then the “grinder” is much more effective than hand-held abrasive tools and devices. The main thing is to choose the right nozzle. This article will help you understand their main modifications and specific application.

Rough stripping of wood

Disc plane

This attachment almost completely replaces this hand tool.

An irreplaceable thing if, for example, you need to rough-process a log - when erecting a log house, preparing fence supports, and so on.

Features of application:

• In this case, the protective cover can be removed. This nozzle is solid and does not collapse. But protection from flying wood chips (glasses, thick clothing, gloves) is required.
• It is allowed to work only with a grinder, in which a second handle is provided (or installed). The angle grinder must be held with both hands when roughing wood.

Roughing disc

The main purpose of such attachments is to remove bark from wood and trim the workpiece. If the “grinder” is in skillful hands, then with such a device you can make a selection of material. For example, if it is necessary to cut out a bowl. If it is being built log house, then an angle grinder with such an attachment perfectly replaces a carpenter’s axe.

In some cases, sawing can be done with a roughing disc. True, the cut will be wide, and there will be a lot of waste (shavings, sawdust).

Milling

Discs

These nozzles are available in various designs. The main difference between the devices is the size of the abrasive grains.

In terms of specific application, they are not much different from rasps. The only difference is the execution speed technological operation. With certain skills, it is advisable to use these for finishing wood.

Milling cutters

They exist, and especially for wood. The assortment is significant, since nozzles of this type differ in the configuration, location and size of the teeth.

Purpose of cutters:

• Selection of grooves.
• Pre-alignment of edges.
• Bowl cutout.
• Sawing (for wooden blanks small section).

Application specifics:

• When processing wood with such attachments, it is prohibited to dismantle the protective casing.
• Each product has instructions. It clearly indicates what types of work this attachment is intended for, the recommended speed of the grinder, and so on.

Sanding wood

If you decipher the abbreviation angle grinder, it is clear that finishing is the main purpose of the “grinder”.

Cord brushes

They are used primarily for primary (rough) sanding of wood, when it is necessary to smooth out the unevenness of the sample.

End discs

The name speaks for itself. These attachments are used to process the end parts of wooden blanks (cuts). They are especially effective if you have to deal with corner (oblique) cuts.

Petal attachments

The most used grinding devices for grinders.

Such attachments are used sequentially, so you will need several of them to process wood. Grinding begins with a disk with a “coarse” abrasive, and gradually its grain size must be reduced. Consequently, the devices change periodically during the work on the grinder.

Grinding wheels

The most universal adaptation to the grinder. It alone is quite enough for varying degrees of grinding. The attachment itself is a metal base on which circles with one or another grain size are attached. They are easily changed either as they wear out, or in case of moving to another area of ​​work. Therefore, only circles are consumables. The nozzle itself can be used for an unlimited time.

Application specifics:

• Sanding wood.
• Parquet scraping.
• Processing of edges and ends.
• Stripping wood before painting.

Wood polishing

For these purposes, brushes and discs are used. Their “working elements” can be made of sponge, felt, fine-grained sandpaper and a number of other materials.

The article provides examples of only the main types of attachments for an angle grinder. There are quite a lot of products in this class, so it’s easy to choose the best device for processing any wood. The author hopes that the information provided will help the reader with this.

On a note!

Wood processing also means its cutting (sawing). Sometimes, when manufacturing piece parts, you have to adjust them to the installation site even before you start grinding the sample. Some “craftsmen” (and there are many of them among friends and on the Internet) recommend using for such operations. Strictly prohibited! Here are just the main reasons why this should not be done.

• “Bulgarian” is a high-speed machine. And although the metal from which the cutting discs are made is durable, it does not withstand this mode for long. More precisely, cutting edges(teeth), which are fixed by soldering. During intensive work, they fall off and fly apart, and with great speed. The consequences are easy to predict.
• Not all discs in size (primarily, outer diameter) are suitable for installation on angle grinders. This means you will have to dismantle the protective casing. The same thing - you can forget about employee safety.
• The structure of wood (even hardwood) is quite loose. Therefore, there is a high probability that saw blade due to constant vibration it may jam. How will the “grinder” behave in similar situation, given its power and speed, no one can predict. But it’s clear that it can easily escape from your hands.
• Constant changes in mode (for the same reason - the viscosity of lumber) lead to systematic overheating of the angle grinder engine. If used this way, the grinder will not last long.

That is why wood processing with its help is carried out only superficially - rough stripping, sanding, brushing. And for cutting you should use sawing tools and mechanisms (hacksaw, circular saw, electric jigsaw, and so on).

Disc brush - designed for processing and cleaning surfaces from dirt, rust, varnish, welding seam; the range of work is quite wide both in everyday life and in any industry.
It is used in conjunction with a grinder or drill. These brushes come in different shapes, size, also differ in hair thickness, some are very hard, some are softer.
Let's look at them in more detail.

Brushes for angle grinders

Various shapes

1. They can be easily distinguished by the hole in the center of the circle with a diameter of 22.2 mm; they are installed like ordinary cutting discs, put on and tightened with a nut. Some come with a nut, you just need to screw them onto the thread.
   Brushes differ in diameter, there are for small and large grinders (from 115 to 200mm).
2. The thickness of the hair may vary depending on the type of work. Hard brushes have a thickness of 0.5mm, softer brushes have a thickness of 0.3mm. For a gentle regime, so as not to particularly damage the surface, it is better to use a soft one to clean the weld seam would be better suited hard bristles made of hardened steel wire.
3. The shape of the brushes can be in the form of a disk, this is better for working in bottlenecks, clean out grooves, crawl into hard-to-reach metas. If the surface is large and flat, it is better to use a brush in the form of a cone or a cup; the work will go much faster than when using a flat one.

Hard and soft

1. They can be easily distinguished by the pin in the center, which is needed to secure it into the cartridge.
2. The size range is smaller than for grinders (up to 100mm).
3. The shape can be either flat or in the form of a cup, cone, you select it for a specific task.
4. Brushes differ in degree of hardness, different thickness hair: 0.3mm and 0.5mm.

There are also polymer-abrasive brushes for drills.

More flexible than metal

These can be used to clean varnish and shallow rust. Their advantage over wire ones is that they are more flexible and will fit into difficult places. Or for example, if the subject complex shape, very grooved, it is also convenient to use such a brush. It is certainly not suitable for hard processing.

One of the most popular tools for repair and construction work, both in domestic and professional use, is considered to be an angle grinder, or angle grinder.

A grinder, like any working tool with an electric mechanism, is especially susceptible to stress. Despite the protective shock-resistant housing, small elements of dirt and dust get inside, which sooner or later leads to failure of individual parts or the entire mechanism as a whole, namely, the contact between the commutator and the brushes is disrupted. In progress of this instrument with metal being a conductor, the penetration of its particles into the part of the contact location of the commutator and brushes leads to short-circuiting and overheating of the copper plates. This, in turn, leads to melting and increased burnout of the brushes, as evidenced by the sparks that appear.

Since when using an angle grinder you cannot avoid various kinds contamination (sawdust, dust, etc.), replacing brushes is an essential condition proper operation tool. Moreover, brushes are most susceptible to wear. It is not surprising that failed brushes spark and burn. The brush is a hexagon with parallel equal edges and an electrical contact, which conducts current to the commutator.

If the grinder suddenly starts to jerk or jerk during operation, the first thing you need to do is look at the brushes. If their wear is not detected in a timely manner, a burning smell will arise, and the tool itself will stop working altogether.

Thus, for safe and efficient work grinders, it is necessary to control the mechanism of action of the electric brushes, and for preventive purposes, regularly clean the commutator.

In most models of grinders, electric brushes are located inside the handle (see photo). This arrangement is due to savings in the production of the body, as well as more comfortable operation of the tool due to its compactness. On some other models, for the convenience of quickly replacing brushes, the screws are located directly on the body. In any case, it is more advisable when replacing brushes to also clean and lubricate the entire tool, and for this it must be disassembled.

Regardless of the location of the electric brush, first you need to disconnect it from the electric circuit of the angle grinder. The tips are removed, a visual inspection of the holder structure is made, and the brushes are pulled out, as shown in the photo. If chips, abrasions or other signs of wear are found, they are replaced with new ones.

Usually, a spare belt is given along with the grinder upon purchase. a set that includes brushes. They can also be purchased at any specialty store. It can be difficult to find suitable ones for some models of grinders, so purchase slightly larger brushes the right size and carefully filed. If the tips are different, the leash from the old brush is attached to the new one.

Interskol

For Interskol angle grinder models, in order to remove the brushes, you need to remove the back cover of the stator housing. Then the screws from the holder are unscrewed.

Wear of elements is determined by their residual length. The length of working carbon brushes cannot be less than 5 mm. For a more detailed study of the technology of changing brushes, you can watch the video.

Bosch

Access to the electric brushes on Bosch angle grinders is achieved by opening the handle of the stator housing, which is held on by a screw. The length of working carbon-type electric brushes must be at least 8 mm. By the way, carbon electric brushes for Bosch are distinguished by the presence of a device that stops the operation of the tool when the brushes reach their minimum operating length.

Makita

In the Makita angle grinder, the screw is unscrewed and the back cover of the case is removed. The Makita 9565 model uses carbon brushes with auto-off.

Selection of electric brushes

Brushes differ in size, shape, and material of manufacture. Previously, they were produced in the form of a structure consisting of copper wire and a conductive brush. But due to very rapid wear and tear, it was decided to modernize this design. Currently, electric brushes are produced by pressing at high temperatures carbon material.

These replaceable elements of the mechanism should not be underestimated, because the service life of the engine depends on the correct operation of the brushes, because by replacing the brushes in time, you can protect the angle grinder from destruction of the armature commutator plate.

Types of brushes:

1. Graphite brushes. During production, graphite is bonded to a special composition, to which carbon black can be added. Next, molding occurs under pressure, and then firing. The difference in the production of such brushes is due to the fact that the material is given additional strength and wear resistance. They are made from carbon materials (graphite, carbon black) and binders. After the standard molding procedure, graphitization follows, which involves firing at a temperature of 2500-2600°C in specialized furnaces. Such electric brushes are the most common for using grinders. Despite the relatively increased price category, the advantages of the properties outweigh the high cost;
2. Carbon brushes. The main material for the production of these brushes does not differ from graphite. The difference between the production technology is the absence of heat treatment, which reduces production costs. Hence the low price tag in stores. But the wear resistance of such brushes is insignificant.
3. Metal-graphite brushes. The composition of raw materials for making brushes includes not only graphite powder, but also metal. Mostly copper powder is added, but lead, tin or silver may also be added. Wherein metal base The composition contains about 80% powder. Such brushes are used in generators and electric motors, because They are characterized by high wear resistance and reliability. But they are very rarely used in household electrical appliances. The price category is high.

Before buying electric brushes, it is better to look in the instructions or technical notes. in the grinder's passport, which brushes the manufacturer recommends. You can also consult service centers about choosing the right brushes.