The need to obtain a smooth surface free of flaws arises not only in industry, in the manufacture of various types of parts, but also at home. The result is achieved through mechanical processing with special tools or machines. Grinding is impossible without a variable selection of various equipment depending on the task being performed: removing paint and cleaning rust before painting, preparing a metal workpiece, sharpening blades, knives, axes, saw chains and discs, and even processing before coating. From this we can conclude that abrasive grinding discs are a universal tool, actively used not only in industry, but also by home craftsmen.

What is a grinding wheel?

It belongs to the cutting abrasive group, used on machines of the same name for manual processing of various types of parts. This gives the product an attractive appearance, as well as the necessary technical characteristics. As a result of mechanical action, irregularities and relief disappear.

The surface of the wheel is porous, many abrasive grains are applied to it, as well as natural and artificial binders.

The main material for production is a composite consisting of a strong base, which is evenly filled with small cutting grains. Initially, the role of an abrasive was played by hard sandstones and other artificial materials, but now they have been completely replaced by artificial ones.

The circle consists of 3 elements:

• abrasive grains;
• ligament;
• pores.

The connecting element is responsible for operational safety. It is necessary to hold the clutch in place at high speeds. The grains ensure an open structure of the grinding wheel. This makes it easier for coolant to enter the work area and move chips away from the grinding area. Quality tools support trouble-free sanding. Thanks to the operation of the wheel at high speeds, the grains easily crush heavy and durable material, showing precise work.

Solid particles eliminate unnecessary elements and effectively act on the surface. It is allowed to process coatings made from carbon steel, ductile iron, durable plastic, bronze, non-ferrous metal, glass and wrought iron.

Grinding wheels are capable of cutting bricks, roofing slate, drywall, ceramic and concrete products. They facilitate impact on various surfaces; with their help, grooves and sections of the required depth and shape are made.

Where is it used?

Polishing is actively used not only in industry, but also in everyday life. This is justified by the attractive appearance of the polished surface and the need to impart certain technical characteristics. Interior elements, timber and panel elements are exposed during the fitting of parts. Particular attention is paid to the degree of surface smoothness in the driving units. Neglect will cause the equipment to quickly fail, since good fit of parts and minimization of friction are critical.

Straight grinding discs are actively used to remove rust and other types of contaminants from metal. Abrasive wheels for sharpening machines make sharpening sharp cutting tools easier.

The product is beloved by jewelers who polish precious metals. They are involved in working with semi-precious stones and ornamental minerals.

The variable shape makes it easier to machine and grind the surface of a curved object. Moreover, the abrasive itself can act as a template for the profile of the plane being processed. For fine grinding, discs with fine grain and soft bond are used. They are gently applied to the part to give it the required level of cleanliness.

There are grinding attachments for the drill. They act as indispensable assistants during renovation activities (cleaning walls before laying tiles, etc.). Installation on an electronic sharpener makes it easier to remove rust and old paint from pipes.

Wheels with a tail belong to a separate category; they are needed for working with hand-held power tools equipped with clamping chucks.

Grain classification

One of the defining characteristics. The result obtained, the size of wear, productivity, and the thickness of the layer removed in one pass depend on it. When choosing, take into account the requirements for surface cleanliness and the nature of the grinding operation. As the grain size decreases, the purity of the processing increases. This reduces the speed of work. For face grinding and finishing of copper and brass parts, it is recommended to use coarse-grained nozzles.

Coarse-grained circles are relevant for:

• flat face grinding with a large contact area;
• when working on machines with high power and rigidity;
• finishing material that clogs the pores of the wheel and greases;
• roughing and preliminary preparation with large cutting depths and removal of large allowances.

Medium and fine-grained are used in cases where processing accuracy comes first:

• when obtaining a roughness of 0.32 - 0.08 microns;
• impact on hardened steel and hard alloys;
• final grinding and finishing of equipment;
• turning.

The described characteristic is measured in microns. There are two marking systems:

1. GOST 3647-80 Soviet standard, with a numerical designation system. The number one corresponds to 10 microns. In other words, 20 is 200 microns.
2. GOST R. 52381-2005. The standard is based on the globally accepted FEPA marking. The letter F and a specific number are used to indicate grain size. The numerical value is the reciprocal of the abrasive size. For example, F70 = 200 - 250 microns, and F40 is equal to 400 - 500 microns.

Types of abrasive

The use of materials is regulated by GOST 28818. The product must be hard, have low thermal conductivity, resistant to frictional wear (the combined effect of sliding speed and high pressure), and have high surface hardness.

The above requirements meet:

1. Electrocorundum on bauxite with a base of high-percentage aluminum oxide and calcium oxide. It is characterized by increased hardness, which remains unchanged even when exposed to high temperatures, which invariably occur at the point of contact with the object. Such products are marked as follows: 12A ... 15 A (normal), 22A ... 25A (white). The strength index increases with increasing hardness of the base substance.
2. Electrocorundum with carbide base. The most common contents of chromium, titanium, zirconium and silicon carbides. Markings start from 38A (zirconium only) to 95A (chrome and titanium). Metals are resistant to shear stress. Thanks to this, they can be used to remove the top layers of a part after heat treatment or straightening them. Due to silicon carbide (52C - 65C), resistance to temperature changes increases; as a rule, they are used when working with non-ferrous metals, alloys and cast iron.
3. Spherocorundum. To obtain it, molten aluminum oxide is blown. As a result, it acquires a spherical grain shape (in electrocorundum they are mostly flat). The abrasive gains high hardness. It is marked with the designation ES. Spherocorundum is used for grinding materials of increased hardness.
4. Monocorundum (43A - 45A). The main difference from other abrasives is the grain structure, here it is monocrystalline. This feature had a positive effect on service life. The disadvantages include high cost, since growing monocrystalline grains is a complex and labor-intensive process. A more affordable alternative includes aggregated monocorundum, obtained by combining poly and monocrystalline sections.

Types of ligaments

The second most important component. The scope of application depends on it. Acts as a connecting link that prevents the destruction of the abrasive mass. The bond affects the type of attachment to the body base. As an example, we can mention a film mount, which is compatible only with ceramic ones and is not at all suitable for bakelite ones.

The following types are distinguished:

1. Bakelite. It is characterized by high polishing qualities. Disadvantages include low resistance to aggressive chemical environments and limitations in rotation speed (for manual machines). Bakelite bonded tools are heavy and suitable for working with metal. The main scope of application is finishing. Allows flat grinding and sharpening.
2. Ceramic. The most popular group. Its components are of inorganic origin (clay, quartz, sand, etc.). The components are ground before adding. The result is a hard but fragile circle. The low weight allows the product to be accelerated to high speeds, but it must be protected from bending loads, since it has a low coefficient of resistance to mechanical stress. Received fire-resistant qualities superior to competitors. Chemical resistance is at a decent level. Maintains edge profile well.
3. Magnesian and silicate. Low strength is compensated by minimal heat generation during operation. The group is sensitive to coolants.
4. Vulcanite. The basis is synthetic rubber that has undergone heat treatment. In other words, it has gone through a vulcanization process. Due to its dense structure, it generates an increased amount of heat. Needs periodic breaks, otherwise it will soften to such an extent that the result will suffer. Strict adherence to operating standards guarantees an impeccable result. Considering this circumstance, the bond is in demand for finishing complex shaped planes and in profile grinding. The purchase will result in significant financial losses.
5. Metal. In demand for finishing superhard alloys.

Type of grinding fluid

Has a significant impact on the final result. They lubricate the circle, and thereby reduce the amount of heat dissipated.

In other words, liquid is needed for cooling, since distortion occurs when heated. In addition, friction between the equipment and the chip is reduced. Reducing the load improves the quality of the finish. And the most obvious function of coolant is to keep your work area clean.

1. Synthetic. The composition does not contain mineral oil. Contains corrosion inhibitors and wetting agents. They dissolve easily in water and form a transparent layer. Lubricating and cooling qualities at the appropriate level contributed to the involvement of this group in machine maintenance.
2. Emulsion. A symbiosis of two liquids that do not dissolve in each other. The composition contains from 30% to 70% mineral oil with corrosion inhibitors and wetting agents. Liquids are represented by opaque milky solutions.
3. Semi-synthetic. A mixture of synthetic and natural emulsifiers. When dissolved in water, the group forms a translucent consistency. Contains 10% - 30% mineral oil, anti-corrosion inhibitors and wetting agents.

The choice of coolant is influenced by the specifics of the tool and the cutting method. Special attention must be paid to the water used and its hardness. It is important to determine the degree of surface contamination and the filtration system.

Hardness

The characteristic determines the ability of the grain to maintain its shape under the influence of external factors. As it decreases, the rate of destruction of the abrasive increases. The grain must fully exhaust its resource. After this, fall out and reveal the next layer of abrasive. The most common equipment is with average hardness. But the choice is influenced by the type of tool used and the material that needs to be finished. The quality of work depends on the decision. An insufficient level will lead to rapid wear of the equipment, excessive hardness will negatively affect the surface being finished, cracks, burns and chips will occur.

Marked as follows:

• M - soft;
• ST - medium hard;
• T - solid;
• CT - extremely hard.

Form

1. Flat circles with straight profile (PP1). The main area of ​​application is sharpening. As a rule, the end is used as a working surface. They are suitable for round, external, internal, centerless grinding and flat machining around the periphery of the wheel.
2. With ring profile. They have an extended end. A technical feature has increased the processing area. Performs similar tasks.
3. With double-sided conical profile. The shape makes it easier to finish various types of recesses. Particularly suitable for grinding teeth, gears and threads.
4. With double-sided groove. Will interfere with the object in the clamping flanges. Due to this, it is not only polished, but also the end is trimmed. In demand for centerless grinding.
5. Cylindrical and conical circles-cups. Suitable for sharpening and flat grinding. The shape is similar to straight profile circles with a conical groove. The difference lies in the end, placed at right angles to the plane.
6. Disc-shaped. The specific configuration and small size of the end made the group in demand for sharpening and finishing the front edges and teeth of slotting tools.

What are they?

1. Velcro. Made from leather on a Velcro base. It is mounted on a support with a self-adhesive backing. The texture is in demand in wood and metalworking, repair, construction and is considered consumable. The minimum size is 125 mm. The grain size is variable. It is marked in different colors (brown - wood and metal, blue - stainless steel, black - minerals). The classic set includes felting, polishing and sanding patterns. Thanks to this, it is possible to finish almost any surface. Installed on grinders, eccentric sanders and hand drills.
2. Petalaceae. A highly specialized group that received an emery base. It has the same shape; they mainly resort to processing wooden planes. It is used for primary polishing and grinding. Made in the shape of a fan. The design provides increased wear resistance. Sufficient for processing up to 10 km2.
3. Fiber. The base is obtained by processing cellulose. Used for cleaning welding seams, spatter, processing steel, non-ferrous and ferrous metals.
4. Diamond. The group is characterized by an optimal balance of fragility and strength with an impressive working margin. Used to interact with carbide materials, ceramics, precious and ornamental stones.

How to determine the grain size value?

Several standards for determining grain size make establishing this value not the easiest task. To simplify the task, a special table of grinding wheel grit size was developed. It provides the designation of grain size according to GOST 3647-80, as well as according to GOST 9206-80 (for diamond chips) and the average size of abrasive particles in microns. Thanks to this, customers can easily select the grit size of the grinding wheel with different types of product markings.

Grinding wheel grit ratio table

Designation according to GOST 3647-80	Designation according to GOST 9206-80 (diamond powders)	Size, microns	FEPA
			Designation for abrasive materials excluding flexible materials	Average size, microns
F 4	4890
F 5	4125
F 6	3460
F 7	2900
200	2500/2000	2500-2000	F 8	2460
			F 10	2085
160	2000/1600	2000-1600	F 12	1765
125	1600/1250	1600-1250	F 14	1470
100	1250/1000	1250-1000	F 16	1230
			F 20	1040
80	1000/800	1000-800	F 22	885
63	800/630	800-630	F 24	745
50	630/500	630-500	F 30	625
			F 36	525
40	500/400	500-400	F 40	438
32	400/315	400-315	F 46	370
25	315/250	315-250	F 54	310
			F 60	260
20	250/200	250-200	F 70	218
16	200/160	200-160	F 80	185
12	160/125	160-125	F 90	154
			F 100	129
10	125/100	125-100	F 120	109
8	100/80	100-80	F 150	82
			6	80/63	80-63	F 180	69
5, M63	63/50	63-50	F 220	58
			F 230	53
4, M50	50/40	50-40	F 240	44,5
			M40	40/28	40-28	F 280	36,5
F 320	29,2
M28	28/20	28-20	F 360	22,8
			M20	20/14	20-14	F 400	17,3
M14	14/10	14-10				F 500	12,8
			M7	10/7	10-7	F 600	9,3
M5	7/5	7-5	F 800	6,5
			M3	5/3	5-3	F 1000	4,5
3/2	3-2	F 1200	3,0
	2/1	2-1	F 1500	2,0
			F 2000	1,2
1/0	1 and
1/0,5	1-0,5
0,5/0,1	0,5-0,1
0,5/0	0.5 and
0,3/0	0.3 and
0,1/0	0.1 and

To select the optimal grinding disc grit value, you must take into account:

• the amount of allowance removed,
• specified surface roughness and other factors.

For example, if it is necessary to reduce the surface roughness, then you will need to choose a wheel with a smaller grain size. It is not always advisable to choose a wheel with too fine a grain, since in this case the material being processed may be burned and the wheel itself may become greasy. We should not forget that the use of a wheel with fine grain entails a decrease in the productivity of mechanical processing of the material.

How to choose?

Before you make a choice, you need to determine the capabilities of the sharpening machine. We are talking about power, operating speed and whether they can be adjusted. It is necessary to find out how important cooling and lubrication are. Violation of the manufacturer's recommendations will lead to the fact that the abrasive will quickly lose its qualities and the object being processed will be damaged.

The following parameters deserve careful attention.

1. Grain. Depends on the nature of the work performed and the surface. Accurate and precise processing will require products with medium to fine grain. When it comes to rough finishing of an object, interaction with materials that pores clog the surface, they resort to coarse-grained equipment. The smaller the grain size, the slower the operation progresses.
2. Diameter. The parameter must match the cutting tool. Universal products received a diameter of 125 - 150 mm. They are lightweight and help in solving various household tasks. The study of the parameters of the mounting hole deserves special attention. The standard values ​​are 22 and 32 mm. For a drill, 10 mm is relevant.
3. What material are they working with? It is important to ensure that the abrasive matches the finishing material. The relevant information is presented in drawings (stone, concrete, ceramics, metal, etc.) on the product. Circles can be universal.
4. Rotational speed. The characteristic must exceed the maximum permissible performance of the grinding machine. It varies from 50 to 100 m/s. Marked in different colors (green 100 m/s, red 80 m/s, yellow 63 m/s).
5. Thickness. Standard sizes range from 1 to 5 mm. It affects the speed and accuracy of the cut. The thin disc cuts efficiently and quickly, but quickly becomes unusable. When interacting with hard metals, they bend and break.
6. Bundle type. It determines the nature of the work performed and durability. Each group performs well when performing certain tasks.
7. Class of imbalance. Affects balance. Thorough mixing of grains and binders will eliminate the existence of heavy and light areas on the surface. The balanced disc rotates evenly and finishes the surface well. The characteristic affects the service life. There are 4 classes of imbalance (1st is considered the most accurate).
8. Hardness. The most common ones are considered to be with an average indicator. The choice depends on the material and tool.
9. Circle density (structure). It indicates the distance between two grains. Highlight:

• closed - for metals and aggressive grinding;
• semi-open - non-ferrous metals, paints and varnishes, plastic;
• open - wood finish.

Purpose of discs and attachments

Grinder circles differ in purpose for:

• cutting;
• roughing
• grinding;
• sharpening

Cutting discs

The most common task performed with a grinder is cutting various materials. The choice of tool material also depends on what material will need to be cut.

1. Metal cutting. The metal cutting disc is made from crystalline alumina corundum, as well as from synthetic corundum called electrocorundum. The main color of metal cutting wheels is blue.

2. Cutting stone and concrete. To cut stone, you should choose a disk made of another abrasive material - silicon carbide. This abrasive easily cuts white brick (silicate) and slate. But to cut red brick, some types of concrete or ceramic tiles, this wheel material is not suitable. Stone discs are available in green.

3. Cutting ceramic tiles, red brick, porcelain tiles and concrete. A diamond disc is already used for these purposes.

   
   This attachment is made of metal; an abrasive mass with diamond chips is applied to the cutting edge. The picture above shows a segmented saw blade designed for dry cutting of material. All-metal discs require water cooling during operation.

4. Wood cutting. Although there are saw blades for wood on sale that are no different from circular saw blades, it is better not to use them for safety reasons. When working with such a tool, the user often suffers serious injuries due to jamming, rebounding, accidental slipping of the tool, etc.

Therefore, if you are still going to use a saw blade on wood, you should adhere to safety precautions. The grinder must have a protective casing and handle installed, and the user must wear a protective mask or goggles. In addition, you cannot cut materials with this tool that are not intended for it.

The safest are considered to be wood discs with a chainsaw chain installed at the end. If the tool jams, the chain remains in place and the disc rotates idle, which reduces the likelihood of injury to the user.

Roughing

If it is necessary to remove a layer of paint or other application, as well as rust from any surface, brushes are used. They come in disc form or in the form of a bowl with built-in metal wire.

The wire in these nozzles can be twisted or loose. Its thickness can also vary. The thicker the wire, the coarser the stripping, the stripping disc or cup-shaped attachment is used, and vice versa.

Grinding

Sanding discs and attachments are used for grinding and polishing various surfaces (metal, wood, plastic and others). Often a flap type grinding wheel is used for grinding. It consists of many “petals” made of sandpaper. The grit of sandpaper can be selected based on the required type of processing (finishing or roughing).

The sandpaper can also be attached to the nozzle using Velcro. Such a tool is screwed onto the angle grinder spindle.

For polishing surfaces, special wheels and attachments are produced that look like felt pads or fabric discs.

Sharpening

To sharpen a tool, sharpening machines (sharpeners) are usually used. But if you don’t have the latter, but have a grinder, then you can purchase a sharpening (grinding) wheel for it, which can easily sharpen almost any cutting tool.

The main difference between grinding wheels and cutting wheels is their thickness (at least 5 mm).

The best abrasive and velcro grinding wheels

Hanko DC341.150.15.0120 150 mm

Got a polyester backing that is high strength and wear resistant. The abrasive was aluminum oxide, and the binder was mineral resins. The equipment guarantees good results. The cutting speed is significantly superior to the competition on paper. Can be installed on eccentric sanders.

Hanko DC341.150.15.0120 150 mm

Advantages:

• Velcro fastening;
• moisture resistance;
• dust-repellent coating;
• long-term operation;
• finishing of wood, metal and paintwork materials is possible;
• made in Korea.

Flaws:

• overheats quickly.

BISON 3592-180-H11 180 mm

The Expert set from the domestic company Zubr is used for preliminary, intermediate and final grinding. It is used to finish wooden and metal products, as well as paint, chrome and nickel plated surfaces. The main feature of the set is a unique glove with an anatomical structure and 10 Velcro attachments.

BISON 3592-180-H11 180 mm

Advantages:

• long-term operation;
• an orthopedic glove improves the quality of processing;
• manual polishing of the car in hard-to-reach places is possible;
• polyurethane nozzle for collecting water on planes with complex terrain.

Flaws:

• diameter 180 mm;
• Skins with a diameter of 150 mm are almost impossible to find.

Hammer 227-001 125 mm

A product from a well-known company that needs no introduction. It has proven itself on the positive side, having been producing equipment for decades. During this time, it has gained the authority of a reliable company with high-quality products.

The new support plate continues the established tradition. It is made of high strength plastic. Fastening is carried out with a standard M14 shank. The model is additionally equipped with an adapter with a drill pin.

Hammer 227-001 125 mm

Advantages:

• convenient adapter for clamping chuck;
• reliable fastening;
• quick installation;
• no play.

Flaws:

• under prolonged loads it quickly fails.

Sanding wheel grit

When purchasing an emery grinding wheel for their machines, consumers pay attention to such a characteristic parameter as grain size. It can take the following values ​​in the standard version - 8, 12, 16, 25, 40. It is clear that 8 are products with the smallest grains, and 40 are, accordingly, the largest.

The choice of grain size should be carried out exclusively professionally. Otherwise, either the sharpening work will be done poorly, or the emery wheel itself will not last long. Fine grit is great for jewelry sharpening, while coarse grit is great for heavy, large tools that do not require high precision.

There is another important parameter that concerns grain - its resistance to abrasion. There are so-called medium-soft products (they are labeled SM), as well as medium-hard ones (respectively, ST). The first option in our country, and throughout the world, has become quite widespread. This is due to the relatively low cost of the product, as well as acceptable characteristics. It works for a long time even under fairly heavy loads. As for medium-hard grain, it is even more resistant to mechanical stress, including abrasion. However, such a product costs many times more, which significantly reduces the economic feasibility of the purchase.

From this perspective, we can consider some examples of product labeling and their appropriateness for use in a given situation. So, for example, an emery wheel marked 150x8x32 12-CM is often used to sharpen skates. What does it mean?

1. The disc has a medium-soft grain, which is relatively cheap and allows for high-quality sharpening.
2. The grain size is 12-H - 12 microns in diameter, if we take the average.
3. 32 mm is the fitting diameter, which is standard for many equipment.
4. 8 mm is the thickness of the product itself. This is a very small indicator, which does not ensure structural strength when working with a large tool under high loads, but it is quite suitable for the intended purpose.
5. 150 diameter sanding wheel.

Let's look at another small example. For everyday life and production, abrasives 150x20x32 25-CM are installed on emery surfaces. In this example, in comparison with the previous one, the width of the product is increased to 20 mm, and the grain diameter is increased to 25 microns. In fact, this turns out to be a fairly universal machine that will allow you to work not only with small tools, such as scissors, knives, screwdrivers, but also with fairly large devices, such as axes and some saws.

Best Flap Abrasive and Grinding Wheels

MESSER 80x50x6 Medium

The model is designed for straight grinders, collet 6 mm. Electrocorundum was used as an abrasive. It performs well when cleaning and matt fine processing of stainless and alloy steels, bronze, copper and aluminum.

MESSER 80x50x6 Medium

Advantages:

• maximum rotation speed - 4800 rpm;
• easy interaction with curved planes and threaded connections;
• variable grain size (100, 180, 320);
• made in Russia.

Flaws:

• diameter - 80 mm.

Bosch X781

The “target audience” of the product is angle grinders. One of the best solutions for treating stainless, sheet and regular steel, as well as cast iron. Productivity at the proper level is maintained by ceramic corundum of increased purity. The role of the binder is performed by synthetic resin and durable X-fabric. The abrasive uses a fiberglass pad.

Bosch X781

Advantages:

• Self-sharpening ceramic abrasive extends service life;
• angular design facilitates finishing of edges, welds and grinding of planes with an angle of 15 - 25;
• diameter - 120 mm;
• light weight.

Flaws:

• not widely available on shelves (they sell out quickly).

DRONCO 5211384

Made from cotton and polyester. This combination gave flexibility, wear resistance and durability. The product does its job quite quickly. The base is fiberglass mesh. It can withstand heavy loads and ensure uniform grinding. Leaves no traces.

DRONCO 5211384

Advantages:

• decorative finishing possible;
• rotation speed 13280 rpm;
• exceeds the wear resistance of competitors 3 times;
• reliable fixation;
• German quality.

Flaws:

• overheats.

Electrocorundum - the basis of white sanding wheels

This kind of product sells out just fine in our country. Moreover, it can be used not only in production, but also in everyday life when working with small and medium-sized tools. It is perfect for sharpening scissors, knives, axes, processing corners, in general - an ideal solution when it comes to non-hard metals.

The presence of high demand, naturally, gives rise to a lot of different offers. The number of manufacturers is growing, as is the range of products. Today it is not difficult to purchase products with a wide variety of characteristics, from grain size to mounting diameters.

In the vast majority of cases, this type of product on sale has a white color, which is provided precisely by electrocorundum. However, in some cases, most often, for marketing purposes, one or another dye may be added to it, which will give a different color.

What is the advantage of this kind of material? First of all, it is necessary to note its softness. This allows you to significantly improve the quality of work, albeit at the expense of the durability of the disk. If sharpening is carried out with ordinary metal, then this indicator still remains quite high. It is very important that the material does not heat up to ultra-high temperatures. This leads to the absence of so-called blue scale on the metal after sharpening. As a result, the metal structure is not destroyed, and the product serves faithfully for many years.

The best fiber abrasive and grinding wheels

Bosch K24 180 mm

The new product is suitable for servicing cars at home and at service stations. The equipment received zirconium corundum of high purity. The role of the binder is performed by a composition of synthetic resins and vulcanized fiber. Suitable for fine and rough grinding, roughing, stripping, removing rust and traces of corrosion from steel and cast iron.

Bosch K24 180 mm

Advantages:

• for clamping on a rubber support plate;
• cleanses carefully;
• high performance.

Flaws:

• non-standard diameter (180 mm);
• not distributed on shelves.

KLINGSPOR 250259

Those who are not used to overpaying, but prefer a quality product, should pay attention to this model from the KLINGSPOR company. German quality will not leave anyone indifferent. The new product has a paper base. Work with stainless steel and aluminum is allowed. The binder was synthetic resins. The wheel does not overheat and prevents the material being processed from tarnishing.

KLINGSPOR 250259

Advantages:

• self-sharpening grain extends service life;
• maximum rpm 12200;
• careful attitude towards the surface being finished and the product;
• zirconium corundum serves as an abrasive;
• affordable price.

Flaws:

• gets very hot.

Characteristics of sanding wheels

The classification of emery wheels is based on their geometric shape. Based on this feature, products can be cylindrical (CC) and conical (CC) cups, disc-shaped (T) disks and others. In everyday life, a flat disk shape with a straight profile (PP) is most often used. Abrasives with a double-sided conical profile (2P) are less relevant in the home workshop, but they are still in demand for sharpening the teeth of saws and other tools.

The next most important parameter of an abrasive disc is its geometric dimensions. It includes diameter, thickness and fit. The latter indicates the size of the mounting hole in the product and in most cases is equal to 32 mm. Exotic abrasives with mounting diameters of less than 10 mm, used for machinist finishing of precision parts, as well as discs with a 76 mm mounting, used for cylindrical and flat grinding, are typical for industry and are difficult to adapt to economic needs. Therefore they are not considered here.

For the same reason, this publication does not focus on discs whose width is not included in the range of 10, 16, 20 and 25 mm. These sizes are optimal for use in private households.

Best Diamond Abrasive and Grinding Wheels

Trio Diamond 340050

The new product has a flexible base coated with diamond. Fastening is realized using Velcro. Compatible with hand sanders. Used for processing concrete, stone, granite and marble.

Trio Diamond 340050

Advantages:

• high quality workmanship;
• effective implementation of assigned tasks;
• moderate wear.

Flaws:

• not installed centrally;
• not standard size.

Matrix 73513

Equipment with a flexible base is designed for finishing granite, ceramics, natural and artificial stone. In particular for the finishing stage. May only be used with coolant.

Matrix 73513

Advantages:

• large working resource;
• Velcro fastening;
• involved in construction, artistic and finishing works;
• Made in Germany.

Flaws:

• Use only with coolant.

How to correctly change a disc on an angle grinder

Since grinder circles are consumables, sooner or later they have to be replaced. They are attached to the angle grinder spindle using a clamping flange (nut) with an M14 thread. To unscrew it, the grinder must come with a special open-end wrench that has pins on one side.

So, to replace the tool on an angle grinder, follow these steps.

1. De-energize the device by unplugging the plug from the socket.
2. Lock the angle grinder spindle using the button located on the front of the body. When you press the button, the stopper enters the hole of the disk installed in the gearbox, which fixes the spindle in a stationary position.

3. Insert the key pins into the holes on the clamping flange.

4. While holding the latch with one hand, turn the wrench to the left (counterclockwise) with the other hand until the nut comes off. Then it can be unscrewed without a key and removed from the shaft.

   
   In this case, the angle grinder spindle rotates clockwise. But in which direction should you unscrew the nut if your device’s shaft rotates counterclockwise? Remember: the pressure flange should always be unscrewed in the direction directly opposite to the rotation of the shaft.

5. Now you can change the tool by first removing the old one.

   
   If you notice that dirt has accumulated inside the casing, you should remove the bottom flange and use a steel brush to remove dirt from all surfaces.

6. Next, you should install the bottom flange in place. You need to install it correctly, making sure to align the grooves on the spindle and flange.
7. Place a gasket on top of the bottom flange. It is not necessary to install it, but it is advisable, since it will ensure easy unscrewing of the clamping nut in the future if you need to change the tool.

8. Install a new tool. Sometimes owners of angle grinders wonder: which side should the circle be placed on? The answer is simple: the disc is placed with the side with the markings on the outside.
9. Place a pad on the abrasive wheel. If your grinder did not come with gaskets, you can purchase them at a specialized store, or cut them yourself from thin tin or cardboard.

10. Screw the flange onto the shaft by hand. Tighten the nut until you can no longer turn it without a wrench. After this, holding the stopper, tighten this nut with a wrench, but no more than a quarter turn, otherwise the disk will begin to deform.

After carrying out the above steps, the replacement of the tool is considered completed.

Green structural elements

However, tools made of non-hard grades of steel are not always used in production and even in everyday life. If we take, as an option, drilling systems, and even the same hammer drills, then an ordinary electrocorundum emery wheel will not be able to effectively cope with sharpening the drill. In this case, manufacturers offer so-called “green” sandpaper mugs. They are named so, naturally, because of their color.

The important aspect is that this type of equipment cannot be used when working with, say, scissors or standard kitchen knives. Upon contact, a very high temperature appears, which leads to instant overheating of the steel and the tool losing its cutting properties. Simply, you can throw it away. It is for this reason that it is not recommended to use a green emery wheel in everyday life. And its cost is disproportionately higher than white.

If we talk about geometric dimensions, they can be exactly the same as those of the electrocorundum analogue. But they can also significantly exceed them, since the main task is to ensure a complex technological process in production, where heavy equipment and machines are used. As a result, for example, the mounting holes can be 76 mm, 127 mm, or even 203 mm.

What parameters need to be considered when choosing an emery wheel?

• External diameter. And here the principle, the more the better, does not work.
• Equipment power. On more powerful machines, consumables can be installed with greater grain size and abrasion resistance.
• Bore hole diameter. Many inexperienced specialists simply forget about this indicator.
• Grit, which, as noted, determines the accuracy of sharpening the tool.
• And an important aspect is the manufacturer. Naturally, it is best to purchase products from well-known brands.

Thus, if you approach the issue of choosing an abrasive as responsibly as possible, and even better, consult with professionals, then the product will last a long time and effectively, paying for itself many times over.

Source: abraflex.ru