A block of sandpaper. We are not stupid! Knife sharpeners that will free you from men's work. How to sharpen a knife correctly

The vast majority of grinding operations in everyday life are carried out manually or using a drill. This is understandable. It is not always advisable to buy expensive specialized equipment for use at home, where grinding operations, as a rule, vary greatly in appearance.

There are various attachments for manual and mechanized grinding. All of them can be divided into two main types.

• Tools that directly process the part itself are hand-held devices, which include grinding blocks (pads, bars) and grinding attachments for a drill or grinder, which are all kinds of support plates and drums.
• Devices that ensure the required position of the grinding tool relative to the workpiece - guides, support surfaces, etc.

A separate type can be attributed to devices for dust extraction, which, due to the abundance and harmfulness of grinding dust, should also not be neglected.

Hand tools for grinding

When working manually, to ensure the necessary processing parameters, a variety of grinding attachments are used.

The simplest hand-held devices include sanding pads, which can be named: sanding blocks, sanding stones, etc. Depending on their shape, they can process both flat and shaped surfaces.

The sanding block consists of three main elements - a body with a working surface on which the sandpaper is pulled, a clamping mechanism that fixes the sandpaper to the block, and a handle, to which force is applied during grinding. The latter as an independent element may be absent, in this case its role is played by the body. The clamping mechanism can also be replaced with other elements that fulfill its function, for example, or with Velcro.

Many types of branded pads are produced, differing from each other in the shape and method of attaching the emery cloth. The body is most often made of plastic, the working surface of which is covered with a soft material that helps smooth out irregularities.

The simplest sanding pads are easy to make yourself. A tree is best suited for this. It is advisable to paste over the work surface or upholstery with a soft material, for example, felt.

The simplest design of a bar is two pieces of board or chipboard, tightened together with screws - so that the skin wraps around the bottom piece, and its ends are clamped between the parts.

With a little more effort, a more functional block can be made, in which the skin will be clamped with a wing nut, which is much faster and more convenient than using screws for this.

For processing large surfaces, if for some reason a power tool is not suitable, it is best to make yourself a grinding "plane". Its possible design is shown in the figure below. It is so simple that it needs no explanation. The dimensions of the device are determined by the specific working conditions - the parameters of the processed plane and the physical data of the worker.

Grinding "plane"

For grinding edges that are strictly 90 ° to an adjacent surface, a tool will be useful to provide the required right angle. It is shown schematically, a specific implementation can be any.

Edge grinding device (end view): 1 - base, 2 - handle, 3 - side stop, 4 - stiffener, 5 - sanding paper, 6 - felt strip.

One of the main tasks in the manufacture of homemade bars is to securely attach the skin to them. In addition to mechanical clamps (using screws, nuts, etc.), other methods of attaching sandpaper can be used in homemade sanding stones.

You can just nail it at the ends with small nails. The method is simple to implement, but inconvenient if you have to frequently change the skin.

An acceptable way to secure the sandpaper is by gluing it. For this, adhesives are suitable, which make it relatively easy to separate the skin from the base when it is replaced.

Sometimes they use wedges to fasten the skin. Cuts are made in the bar, into which the edges of the skin are tucked in and wooden wedges are driven. Saw cuts and wedges come in a wide variety of sizes.

Attachments for drills and grinders

Manual grinding is a waste of time and effort. With significant volumes of grinding work, it is advisable to use a power tool - a drill or grinder, in particular. To convert the latter into a grinding tool, they must be equipped with a suitable grinding attachment - a backing pad or drum.

Sanding pads... These attachments are a disc made of plastic or rubber, to which an emery cloth is attached in the form of a circle. Plastic plates have a soft or not very soft layer between the base and the Velcro, for better adhesion of the skin to the treated surface. Trays for drills have a shank in the form of a rod, for angle grinders - a thread for screwing them onto the output shaft of the grinder. The grinder's grinding attachment can be turned into a drill attachment by screwing an adapter with a shank into it.

But due to the rigidity of the grinder attachment, a strictly vertical arrangement of the drill relative to the plane during grinding is practically impracticable. When using a rigid plate (flexible is easier to work), any slight tilt will bite the edge of the plate into the workpiece and try to pull the drill out of your hands, which leads to an increase in the tilt and deeper nibbling of the edge of the circle. This leads to clearly visible depressions on the surface to be treated. Therefore, only grinding attachments capable of compensating for the tilt of the drill are suitable for the drill: either rubber, or with a thick soft layer between the plastic base and Velcro, or with a movable pin attachment.

Rigid pads are only suitable for working with a fixed drill, such as the one shown below.

If you do not find a suitable nozzle for a grinding drill on sale, and there is a hard nozzle, then you can make a thick soft layer between the plastic base and the Velcro with your own hands.

The velcro is carefully cut off with a clerical (construction) knife, and a large round body wash sponge is glued as a soft layer. When the sponge is compressed during grinding, symmetry may be broken (the Velcro with the sandpaper moves in one direction), but at the speed of the drill (3000 rpm) this is not critical, it may not work with the grinder.

Combined attachments for grinding on a drill are available, in which the shank can be in two positions relative to the working surface - be rigidly locked with it or have a degree of freedom (unlocked). In the latter case, the working surface of the tool has the ability to adapt to the tilt of the drill, so that the processing is obtained without the formation of indentations. But the price of such attachments is close to the price of orbital sanders.

To make the shank movable, a flare nut is twisted (in the photo below with a similar device, it is twisted to the chuck).

The skin is attached to the plates with Velcro. This method of fastening requires a special emery paper, on which a reciprocal layer of Velcro is applied.

Grinding drums... Grinding drums for a drill are a cylinder with a shank, sanding paper is fixed on the cylinder in the form of an endless belt (an emery cloth tape glued together at the ends) or a strip of sandpaper with free ends. In contrast to the support plate, in which the working surface is located perpendicular to the axis of rotation, in the case of drums it is parallel to it.

In order for the skin to sit tightly on the drums, the latter have different tension mechanisms. According to the principle of operation, there are two of them - increasing the outer diameter of the drum (used for an endless belt) and tensioning the abrasive belt using a special mechanism (used for open belts). The increase in the diameter of the drums is realized in different ways - by pumping them (for pneumatic models), compression in the axial direction (for drums with rubber elements). The tension of the open belt can also be performed in different ways. This is most commonly done with a rotating screw that tightens the ends of the sandpaper. Below are several options for drums with different types of skin tension.

A drum for endless sanding belts can be made by placing rubber spacers between the wooden discs. When the axle bolt is tightened, the rubber is crushed, expanding radially and securely fixing the sanding paper on the drum.

Grinding attachments using a drill... Grinding parts with a cymbal or drum while holding a drill in your hands is not as easy as it might seem to someone who has never done it himself. In many cases, a better surface quality can be achieved by holding the tool stationary. Especially when processing small parts that are easy to manipulate by hand. Grinding attachments are available to secure the power tool by making it fully or partially stationary.

You can use proprietary drill guides, which are primarily designed for drilling, but can be successfully used for grinding - mainly with a drum. There are two ways to work with them. Fixing the drill in the guide motionlessly and displacing the workpiece relative to the tool (photo A below), or moving the guides together with the drill relative to the workpiece, pressing the supporting surface of the guides against the latter (photo B below). In either case, drum tilt is eliminated, thereby ensuring surface treatment at the desired angle.

You can independently make the simplest sanding device from two boards, which allows you to ensure the angle of the sanding edge with respect to the main surface is exactly 90 °.

Dust removal... When sanding wood, a lot of dust is generated, which is not only inconvenient, but also harmful to health if inhaled. Dust must be dealt with. The easiest way to do this is to suck it off with a vacuum cleaner by placing the hose closer to the sanding area.

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In this article, we will focus on tools that make it easier to process such as grinding surfaces. Of course, for chipboard, this topic is not very relevant (although there are exceptions), but for wood, grinding is an integral part of product processing.

Of course, if you work professionally with wood, then you most likely already have several types of grinders, but if there is no extra money for this, and you are carpentry at the behest of your soul, then this material is for you.

Fixture No. 1Grinding block necessary when sanding some kind of smooth surface (or a surface that should become such). When sanding by hand, it will not work to smooth out irregularities only for the reason that our palm is not smooth.

Making the simplest sanding block with your own hands is as easy as shelling pears. To do this, you need 2 identical planks (pieces of chipboard), a pair of self-tapping screws 26-30 mm and a piece of sandpaper.

We wrap the bottom block with sandpaper so that it covers the entire lower part and goes up at least 2 cm (more is better). It is desirable to wrap it in tension so that the paper adheres tightly to the surface. We press it with a second bar and tighten them with self-tapping screws (ideally, the self-tapping screws should pierce the edges of the paper bent from the inside, so it will definitely not slip out.

That's it - quick and easy. The replacement of the skin, as you probably already guessed, is carried out with a complete disassembly.

Fixture No. 2Untitled serves for the manufacture of round blanks from a bar. In other words, getting smooth wooden cylinders. Then they can be used in different ways, for example, as a lattice in a crib, for making arrows or as "logs" when building a model of a fortress or a raft with a child.

For manufacturing, we take two planks and trim the processed bar (I use it to make arrows, which means that a simple window glazing bead acts as a bar). We glue the coarse-grained skin on the planks (one sheet on both and from the edges with small nails or self-tapping screws we fix the bars-limiters.

The principle of operation of the device is that it does not allow to grind off the "extra" material that does not go beyond the limiters, but it removes all corners that go beyond the boundaries of the cylinder.

The workpiece is clamped into a drill chuck (pre-mounted on a workbench) and inserted into an open device. After that, the flaps are covered, the drill turns on. Without applying effort (otherwise the twisting force will be too large and the workpiece will simply break) gradually close the device until it is completely closed by the stops. After that, we remove it, the final finishing - with a fine sandpaper, already clenched in a fist.

It is advisable to grind the bars, previously planed to the state of an octahedron.

Evolutionary development moves in a spiral, each time returning to previous technologies, but at a new level. This formula can be applied to knife sharpeners. Since ancient times, people have sharpened piercing and cutting tools using natural stone. Then emery was developed - artificial rough stones of a round shape, mounted on a rotating axis.

Such a sharpener made it possible to sharpen a lot of tools in a short time without physical costs. The next stage is high-tech electric ceramic sharpeners.

All these devices really simplify the process, but there is a significant disadvantage.

Even at medium speed (foot-operated emery does not count), the abrasion of the abrasive against the metal results in intense heat. If you gape a little and press the knife too hard, the so-called metal release occurs. A blade hardened during production becomes softer and dulling occurs faster.

Therefore, real craftsmen have never used mechanical emery. And modern materials have returned to use the usual bars for sharpening knives, only they are made at a high technological level.

The main types of bars, stones used for sharpening, dressing and honing in our country before the collapse of the USSR

Natural whetstones

Arkansas stone (scientific name - novaculite)

Arkansas is considered his homeland, hence the name. It consists of small crystals of quartz with sharp edges, compressed in a natural way. It is these edges that remove metal with precision precision in a thin layer, performing high-quality sharpening.

It is mined in deposits, the number of which can be counted on the fingers of one hand. This process is expensive, which justifies the high cost of the products. Such devices are used by craftsmen - experience is required to properly sharpen a knife with a bar of novaculite. Sharpening technology involves wetting the surface with oil.

The country of origin is clear from the name. These knife sharpeners are softer than Arkansas. On the one hand, the quality of sharpening is higher, the reverse side of the coin is rapid wear. Therefore, Japanese stones have to be regularly restored to their original state, in other words, they are periodically grinded against a harder emery.

They work on them exclusively in a wet state, then a micro abrasive suspension forms on the surface, which is the grinding layer. Hence the name - water. This is a tool of true professionals, the cost of a natural stone can be thousands of dollars.

Artificial bars

With the advent of new technologies, grinding stones began to be produced industrially. This reduced the cost, but the quality still falls short of natural materials. As an exception, there are artificial water stones. The finest structure (grain size from 7 microns - from 20 microns) does not occur in nature.

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What are the bars made of?
These are two materials, evenly mixed and bonded under high pressure and temperature. Working fraction - acute-angled crystals of silicon carbide, corundum or chromium oxide. These stones are much stronger than steel, and when in contact with the blade, they cut the metal layer by layer.

To keep the grains in the body of the bar, a bunch, or base, is used. This material is softer than steel, and the softer it is than working crystals. Waste solids gradually fall out of the base layer by layer. As you grind, the knife sharpening bars resume their characteristics.

Sharpening bars lose their shape from constant use. Learn more about aligning sharpening stones in this video.

Of course, these are not rectangular diamonds. The working fraction is artificially grown microscopic crystals. And still, the cost of such a sharpening tool is quite high. Diamond grit can be mono- and polycrystalline. Differs in the number of working faces.


There are two types of diamond stones, they differ in the method of fixing the working crystals:

Fired Ceramic Knife Sharpening Bars

This is a separate category altogether. It would be more correct to call this tool a rule. Sharpening a knife on a ceramic block is a tedious task. The grain size is practically zero, the pores are instantly clogged with metal dust. Therefore, such stones are used for the final finishing of the blade after rough sharpening with an ordinary whetstone.

Important! Regardless of the material from which the block is made, you can sharpen a knife with a sharpening stone only if there is lubrication.

This can be spindle oil or machine oil, and for most sticks, plain water. In addition to the main task - to lubricate the surface and form a suspension, the liquid washes away metal particles that clog the pores in the stone.

How to sharpen knives with a bar correctly

The procedure is simple only at first glance. The ability "how?" Is more important than the knowledge "how to sharpen knives?" An experienced chef can make a razor out of a knife using a simple brick, and an inept craftsman can ruin the blade on the most expensive whetstone.

If you are bored of your knife dulling quickly or the sharpening stone chipping away due to its softness, this article is for you. I will tell you how to make a homemade sharpening block that will cope with sharpening a knife as well as Japanese stones. Epoxy resin will be used as a bond, silicon carbide as an abrasive.

What other abrasives are suitable? In addition to silicon carbide, you can use aluminum oxide powder, lapping powder for valves, or grinding powder, which is used in production to polish hardened parts.

There are two options for how to make a bar for sharpening knives with your own hands:

• Way. If you have a green Soviet bar (this is either silicon carbide or corundum), but it crumbles and becomes greasy, you can grind it into powder and get a ready-made abrasive. The photo shows one of these bars

• ready-made powder. It will be enough to buy 100 grams for a bar measuring 160 * 65 mm. This is what I will make.

A 15 mm thick board was chosen as the base on which the abrasive will be fixed. Cut off the desired part to size. We leave one side as it is, sand the other with sandpaper and make cuts with a saw on wood to increase the hook of the epoxy resin.

We will pour the sharpening block into a cardboard box, which must first be glued to size and glue the inside with tape. This is to prevent the resin from sticking to the paper.

Let's get to work. Attention! When working with epoxy glue, I strongly recommend using rubber gloves (ordinary medical). It is best to measure the epoxy with a syringe. That is, you need 2 syringes - one for the resin, the other for the hardener. Dilute the adhesive with hardener according to the instructions (see the ratio of resin to hardener). I purchased resin by weight and I know that the proportions of my glue are 1: 5 (that is, for 1 part of hardener, 5 parts of glue).

First, I will mix 6 resin cubes and 1.2 cube of hardener.

I will stir and pour in a handful of abrasive.

Little by little I add the abrasive and stir until I feel that it is difficult to interfere with the glue. I add resin and silicon carbide again. I do it until the abrasive ends.

It took me 36 cubic meters for 100 grams of powder. resin and 7.2 cubic meters of hardener. These numbers will change as the density of different types of resins is different. If your glue is too thick, warm it up in a water bath before use, just do not bring the water to a boil.

Pour the mixture into a mold and cover with a plate (the side on which the notch is applied).

All that remains is to press it all down with something heavy. Since my box is high, the load does not reach the board, so I put a piece of wood on top. And I press all 2 pancakes from the bar.

Drying time for the glue is 1 day at room temperature, but we will leave our box for 3-4 days so that the glue will polymerize well. It took 4 days, I printed the bar. That's what came out of it.

Cut off the remaining glue on the sides of the bar and chamfer with a file.

As you can see in the photo, the stone is glossy. Therefore, we need to bare its grain (show cutting properties). To do this, take a piece of glass, apply a little water and sprinkle with sand. We put a block on top with an abrasive down and perform movements, as if we were drawing the number "8".

Well, the homemade knife sharpener is ready. In some places, the abrasive is not exposed, since the resin layer is slightly smaller.

I recommend using a homemade whetstone with water (like an ordinary water stone) so that it does not get greasy. As a result, after all our efforts, we have a homemade bar for sharpening knives with a grit of the order of 5000-7000, which even sharpens a quick cut (hardness more than 65 units according to Rockwell). A knife sharpened with this stone shaves hair with ease. I wish that the cutting edge of your kitchen knives will keep sharpening for a long time.

There are a large number of abrasive tools that differ in sharpening method, appearance, configuration and size. A fairly popular sharpening tool is a sanding block. We will consider the features of its use and varieties below.

Grinding stones: composition, principle of operation

Among the wide variety of grinding tools, metal grinding stones play a special role. According to GOST, metal bars have the following forms:

• square;
• rectangular;
• triangular;
• round;
• semicircular.

Grinding flat bars are also distinguished. Any abrasive bar contains two fractional materials mixed with each other. One of them forms abrasive grains of a crystalline form, while the others are distinguished by special hardness, most often it is steel. To hold the grains in a certain shape, a soft material in the form of a matrix is ​​used. In terms of hardness, the matrix should be approximately the same as the material with which the bar is processed. Thus, in the process of sharpening or grinding, the matrix gradually wears away, opening up access to new crystals and abrasive grains. The process of abrasion and wear of the abrasive bar is quite normal, indicating the correctness of its application.

In the presence of a softer matrix, the abrasive does not cope with its work, the sharpening is performed poorly. Since there is no renewal of the abrasive material, and the grains are simply pulled out of the matrix. As a result, the shape of the bar becomes incomprehensible, the processing is not performed accurately.

The abrasive substance in the composition of the bar should have a homogeneous structure of crystalline inclusions. If there are grains of different sizes located on one and the other half of the bar, it is possible to choose the type of sharpening required for a particular device. If small and large grains are located in a chaotic direction, then accurate sharpening cannot be achieved.

However, the construction of a bar with the most identical grains is a rather complicated process, which must be achieved through special efforts, therefore the cost of such a bar will be an order of magnitude higher. However, in the end you get a tool that provides high precision sharpening.

Particular attention should be paid to the shape of abrasive crystals, since their cutting edges are different in shape, and this indicator also affects the quality of sharpening. The quality of the bar directly affects the process of sharpening the product, but the availability of skills in working with this device also plays a special role in this process. Initially, we recommend that you start experimenting with inexpensive bars, gradually moving on to more expensive ones. The length of the bar should be equal to the length of the sharpened blade. In this case, the width of the bar should not be taken into account.

Grinding stone characteristics: product marking

When choosing bars from metal for sharpening, first of all, you need to pay attention to their marking. First of all, the emblem of the company that made it is indicated on the bar. The shape of the bar is also indicated below, which can be rectangular, triangular, semicircular, etc.

After that, the size of the bar is indicated in width, length and height. The quality of the abrasive material and its composition, as well as the characteristics of the grain size. Also in the marking of the material indicate the degree of hardness, as well as the level of proximity of the grains of abrasive purpose.

The main characteristic of the bar is its graininess. There are basic systems for determining the grain size in a grinding stone:

1. FE PA - standards for combining European production of abrasive sharpening, this marking is relevant for most European countries, Russia, Turkey.

2. ANSI is a system of standards common in America, used in the production of abrasive materials.

3. J S I - manufacture of rectangular grinding bars according to Japanese industrial standards.

Some manufacturers do not indicate marking in accordance with these standards; it is better to refuse to purchase such bars.

Features of the use of ceramic abrasive stones

Most often, for the manufacture of a ceramic bar grains of electrocorundum, that is, oxidized aluminum, are used. It is also possible to use silicon carbide in combination with a binder.

The most common among ceramic bars are materials of German, Polish and Chinese production. Moreover, the cost of such bars is much lower than metal ones.

However, during operation, such bars quickly deteriorate, lose their shape and wear off, so they need to be periodically replaced. Also, it is not recommended to work with such material for more than 30 minutes, as they quickly heat up.

In some markets, there are bars produced by the Soviet Union, we recommend that you give your preference to them. As far as the quality is concerned, they are much better than alternative bars from Germany.

There are a huge number of manufacturers of ceramic bars, differing in quality and sharpening time. It is possible to manufacture specialized sharpening bars of a certain shape and size.

In addition, certain manufacturers of ceramic knives also make bars for sharpening them or recommend sharpening knives only with certain bars. Although, to obtain a high-quality sharpening result, it is enough just to have experience in sharpening knives. Among the advantages of ceramic-based knives and bars, we note, first of all, high wear resistance and a long service life. Medium grade ceramics are subject to very slow wear, while fine ceramics are not subject to wear.

However, in the process of working with ceramic bars, they are gradually clogged with small pieces of metal, because of this, their rapid wear occurs. To restore such a bar, it is enough to wipe it with a kitchen cleaner, which is used to clean the pots or with sand combined with liquid soap.

Please note that in the process of working with bars on a ceramic basis, it is recommended to use a special solution in the form of water or water with the addition of soap to avoid heating them. Otherwise, metal dust will quickly clog the surface.

The process of manufacturing ceramic abrasive grinding bars consists in the formation of an abrasive and its further drying. Please note that during firing, certain products are deformed, they cannot be restored and disposed of. If there is a small amount of deflection of no more than half a millimeter, such a bar is suitable for use. If there is a greater deflection on the bar, refuse to buy it. Since in this case, the quality of sharpening will be rather low.

Japanese water stone - sanding block

Considering the composition of an ordinary metal bar and a Japanese stone, one cannot find too many differences. Their principle of operation is the same, however, the quality of sharpening is still determined by such indicators as the size of abrasive grains, their uniform arrangement, homogeneity and hardness of the matrix fiber. The cost of these stones is quite high compared to ordinary stones.

Their main difference from a standard bar is in their softness, to determine which it is necessary to compare the volume of a binder, an abrasive and a connecting component. Since the bar is particularly soft, the degree of wear is higher. However, after working off the grains, when they come into contact with water, a solution is formed on the surface of the stone, which improves the quality of sharpening. Therefore, the productivity of Japanese stones is an order of magnitude higher than that of a conventional bar.

To bring the tool to perfect sharpening, special pastes, compounds and felt circles are not required, just a Japanese stone is enough. This material is never handled dry. They should be well wet. Before work, the stone is placed in a container with water, if there are small air bubbles on the water, start working with the stone. The water absorption time for coarse bars is about 7 minutes. Fine grain models take longer to soak.

Next, the stone is installed on the surface of the holder. It is possible to make it on its own or buy it complete with a stone. The main requirement is that the holder holds the stone in the desired position. Since you will need the work of both hands to sharpen the tool.

When using stones with fine grain, you will need to use a special suspension, while the work becomes rather dirty. Do not rinse the suspension, however, if it thickens, remove it from the surface. It is possible to use a disposable syringe or pulverizer to remove the suspension. If there is a small amount of corrosion on the stone, water with soda or a weak soap solution is used during the work. However, when finishing the blade, no mortar is used.

Try to touch the bar over the entire area, watch the wear on each part of the mechanism. Most often, the central part of the bar is subject to maximum wear. To level the worn-out stone, use bars with cuts on all their surfaces. It is possible to use waterproof sandpaper, with the help of which the damaged block is also leveled.

For storage of such bars, individual containers made of plastic or cardboard are used. Working with such bars is carried out rather slowly and accurately. However, the result is worth it, as the sharpening is better than using conventional metal abrasives purchased on the market.

Abrasive Tool - Diamond Bars

Diamond is one of the hardest materials and is also used in the production of sharpening stones. A diamond sharpening block never changes its shape, which is one of its main advantages. A nickel steel surface is most commonly used to hold the diamond bar. The option of coating a conventional bar with diamond dusting is possible; such materials are less durable and wear out quickly.

Working with a diamond bar is done by periodically moistening it with water. A high quality diamond block is not subject to clogging, therefore, to clean it, it is enough to dip the block in water after work.

Another advantage of a diamond abrasive stone is the rapid abrasion of steel, so the working force of the stone is increased several times compared to ceramic stones. Please note that the size of the diamond stone should be one and a half times the size of the sharpened tool, only in this case it is possible to obtain a high-quality sharpening.

Diamond stones should only be used by professionals with experience with this type of tool. Otherwise, there is a risk of damage to become an inexperienced craftsman.

The main disadvantage of such a device is its high cost, which pays off in the course of its operation. Since the technology for making diamond bars is particularly complex, and the material itself is quite expensive, a diamond bar costs several times more than usual.

Cheap analogues of diamond stones wear out quickly. In any case, when working with an abrasive bar, you do not need to press too hard on the surface, it will not sharpen from this, but, on the contrary, will break. When using brute physical force, diamond crystals are split and the bar is irreversibly damaged. Take special care with the bar you just bought. Such a device should very carefully give in to lapping. The first ten sharpenings are not made as high quality as we would like, this is because the abrasive grains are crumbled from the bar. Further, the sharpening will be perfect.

To determine a fake, it is enough to carry out several sharpenings on a diamond bar, with its uniform baldness, the bar is a fake. Since the original diamond block does not go bald for a very long time, and does not lend itself to wear.