Sharpening diamond block. Sharpening knives: expert advice

"But who sharpens on sharpening bars today?" - another reader chuckles. The fact is that grinding at high speed, for example, on a high-speed grinding wheel, causes strong heating of the processed material, which in our case is fraught with uncontrolled and undesirable spontaneous tempering of the hardened blade, or at least part of the cutting edge of the blade. A thin strip of steel heats up instantly; periodic dipping of the processed blade into water cannot prevent this. Therefore, never sharpen your knives - whether home-grown or branded - on a high-speed grinding wheel, you will most likely ruin the blade irrevocably! It turns out that the quality indicators of a hand-sharpened blade can far surpass the parameters of its counterpart, brought to the average consumer level by factory automated means.

Each bar for sharpening consists of two fractions mechanically mixed with each other: abrasive grains-crystals - a material much harder than the material being processed (in our case, steel), and a matrix of a softer material that holds abrasive grains in a given shape, although would be the same bar.

The hardness of the matrix is ​​usually commensurate with the hardness of the material being processed, sometimes even slightly less. Correctly selected hardness of the matrix allows it to wear off in the process, exposing more and more abrasive grains from the deep layers, while the old, with already worn out, dull cutting edges are crumbled from the bar. In other words, when erasing steel, the abrasive bar is erased and wears out, and this is a normal process of its work. And if the matrix is ​​too soft, the abrasive will sharpen less efficiently because the force on the cutting edges of the abrasive grains will not erase the material being processed, but will tear out the grains from the too soft matrix. In addition, as a result of self-rubbing, the bar will quickly lose the desired shape of the contact surface with the material being processed. The processing will then not be accurate. The matrix is, as a rule, something ceramic, from the simplest fired clay to varieties of technical faience.

The abrasive is characterized by the uniformity of the sizes of abrasive crystals-grains. If the grains are not the same in size, it may turn out that one end of the bar is small and the other is large. And if small and large grains are mixed more or less evenly with each other, as often happens in cheap abrasive tools, then the sharpening is not very accurate, and the result is all the more random, the greater the difference in grain sizes. However, it is extremely difficult to make all the grains the same, therefore the grain size is an interval characteristic. A certain difference lies in the shape of abrasive grains in various abrasives, namely in the sharpness of their cutting edges, which, in turn, depends on the structure of the crystal lattice of a given chemical compound.

Of course, the quality of the bars is very important for good result, however, I would like to make a reservation right away: the quality of sharpening depends much more on the skills of the master than on the quality of the abrasive. I would like to warn beginners against purchasing expensive bars, the price for which can go up to $ 50- $ 100 or more. Start with ordinary "boats" and remember that the abrasive itself, even the best one, without your skills is just a bar.

It is recommended that the block be at least as long as the blade to be sharpened. And it is better one and a half times more (although for the "big chef" - the "senior" knife in the chef's troika - it is almost impossible to find such a bar for a reasonable price). In this case, the width of the bar does not really matter.

Marking

If you go to the flea market for bars (the easiest way to buy at least something worthwhile), it is highly likely that you will come across bars of a domestic manufacturer, moreover, made in the USSR.

2 - type: BP - rectangular bar;
3 - the size of the bar: 25x16x150;

5 - grain size: 18 - 200 ... 160 microns;


8 - structure (degree of convergence of abrasive grains): 8;

10 - accuracy class: B;

1 - the emblem of the manufacturer's plant;

3 - grain size: 6 - 80 ... 63 microns;

5 - the hardness of the abrasive tool: ST1 - medium hardness;
6 - structure (degree of convergence of abrasive grains): 8;
7 - bundle: K - ceramic;
8 - accuracy class: A;
9 - the standard which the bar satisfies: GOST 2456-82;
10 - type: BKv - square bar;
11 - bar size: 20x150.

1 - the emblem of the manufacturer's plant;
2 - abrasive material: 64C - green silicon carbide;
3 - grain size: М28 - 28 ... 20 microns;
4 - the minimum percentage of the main fraction: P - increased;
5 - type: BP - rectangular bar;
6 - the size of the bar: 25.16.150 - 25x16x150;
7 - the hardness of the abrasive tool: ST2 - medium hardness;
8 - structure (degree of convergence of abrasive grains): 10;
9 - bundle: K - ceramic;
10 - a document that the bar satisfies: TU 2 -...;
11 - the state quality mark of the USSR.

1 - the emblem of the manufacturer's plant;
2 - type: BT - triangular bar;
3 - bar size: 16x150;
4 - abrasive material: 25A - white electrocorundum;
5 - grain size: 6 - 80 ... 63 microns;
6 - the minimum percentage of the main fraction: P - increased;
7 - the hardness of the abrasive tool: ST1 - medium hardness;
8 - structure (degree of convergence of abrasive grains): 9;
9 - bundle: K - ceramic;
10 - accuracy class: B;
11 - the standard that the bar satisfies: GOST 2456-82.

We will not consider the rest of the bars in such detail, we will dwell only on the grain size - the main characteristic. There are several systems of standards for determining the grain size in abrasive materials:

FEPA (Federation of European producers of Abrasives) - standards of the Federation of European Producers of Abrasives, adopted in Europe, as well as among the largest manufacturers of abrasives in Russia and the CIS countries, as well as in India, Turkey and South Africa. The grain designation for flexible material, such as abrasive paper, and hard or loose abrasive, such as abrasive stone, is different - respectively P220 and F220.

ANSI (American National Standards Institute) is a system of uniform standards for the US industry, developed by the American National Standards Institute, also applies to the production of abrasive materials.

JIS (Japan Industrial Standards) - Japanese Industrial Standards, a set of requirements applied in the Japanese industry, which also applies to abrasive materials.

Be prepared for the fact that stores often sell knife sharpening bars, not only without detailed markings, as in the photo above, but even without specifying the grain size. Most likely, this is due to the wide range of abrasive grain sizes, and the honesty of the manufacturer. However, if a small skin is sold in the same store, then by comparing the surface of the bar and the skin, you can at least roughly determine the grain size of the bar.

Grain marking by different standards

the USSR			FEPA				ANSI		JIS		Appointment
Designated according to GOST 3647-80	Designated according to GOST 9206-80 (diamond powders)	Size, micron	Designated for abrasive materials, excluding flexible backing materials.	Average size, μm	Designated for abrasive materials on a flexible backing.	Average size, μm	Designated reading	Average size, μm	Designated reading	Average size, μm
			F 4	4890
			F 5	4125
			F 6	3460
			F 7	2900
200	2500/2000	2500-2000	F 8	2460							Very rough work. Cleaning of workpieces, castings.
			F 10	2085
160	2000/1600	2000-1600	F 12	1765	P 12	1815
125	1600/1250	1600-1250	F 14	1470	P 16	1324
100	1250/1000	1250-1000	F 16	1230
			F 20	1040
80	1000/800	1000-800	F 22	885	P 20	1000
63	800/630	800-630	F 24	745	P 24	764	24	708			Renovation work associated with intensive metal removal: restoration and change of the shape and profile of the blade and the cutting edge itself.
50	630/500	630-500	F 30	625	P 30	642	30	632
			F 36	525	P 36	538	36	530
40	500/400	500-400	F 40	438	P 40	425	40	425
32	400/315	400-315	F 46	370	P 50	336	50	348
25	315/250	315-250	F 54	310			60	265
			F 60	260	P 60	269
20	250/200	250-200	F 70	218	P 80	201
16	200/160	200-160	F 80	185	P 100	162	80	190
12	160/125	160-125	F 90	154			100	140			Removing traces of roughing operations, grinding and basic sharpening work.
			F 100	129
10	125/100	125-100	F 120	109	P 120	125	120	115
8	100/80	100-80	F 150	82	P 150	100	150	92
					P 180	82	180	82
6	80/63	80-63	F 180	69	P 220	68	220	68
5, M63	63/50	63-50	F 220	58	P 240	58,5	240	53,0	J 240	60
			F 230	53	P 280	52,2			J 280	52
4, M50	50/40	50-40	F 240	44,5	P 320	46,2			J 320	46
					P 360	40,5			J 360	40
M40	40/28	40-28	F 280	36,5	P 400	35,0	320	36,0	J 400	34	Removal of traces of grinding of the blade surface, fine sharpening and lapping of the cutting tool.
			F 320	29,2	P 500	30,2	360	28,0	J 500	28
M28	28/20	28-20	F 360	22,8	P 600	25,8			J 600	24
					P 800	21,8	400	23,0	J 700	21
M20	20/14	20-14	F 400	17,3	P 1000	18,3	500	20,0	J 800	18
					P 1200	15,3	600	16,0	J 1000	15,5
M14	14/10	14-10	F 500	12,8	P 1500	12,6	800	12,6	J 1200	13	Editing of cutting edges, surface polishing.
					P 2000	10,3	1000	10,3	J 1500	10,5
M10	10/7	10-7	F 600	9,3	P 2500	8,4
M7	7/5	7-5	F 800	6,5			1200	5,5	J 2000	6,7
									J 2500	5,5
M5	5/3	5-3	F 1000	4,5					J 3000	4,0
	3/2	3-2	F 1200	3,0					J 4000	3,0
	2/1	2-1	F 1500	2,0					J 6000	2,0
			F 2000	1,2					J 8000	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

Properties of abrasives used in abrasive stones

Abrasive material	Description	Abrasive ability	Appointment
Corundum	Mineral consisting of crystalline aluminum oxide Al 2 O 3. Microhardness - from 1900 to 2200 kg / mm 2	Low	Finishing operations
Electrocorundum	Artificial corundum obtained by smelting bauxite. Depending on the presence of impurities, normal, white (with a high content of aluminum oxide), chromium (technical ruby), titanium (technical sapphire) and zirconium are distinguished. Microhardness - from 1900 to 2400 kg / mm 2.	Low	A wide range of tasks - roughing, grinding, sharpening and lapping of blades made of carbon and tool steels.
Carborundum	Contains 97-99% silicon carbide SiC. There are two main brands - a harder and more fragile green carborundum and a dark one. Microhardness - from 3300 to 3600 kg / mm 2.	Average
Boron carbide	Chemical formula - B 4 C. Microhardness - from 4000 to 4500 kg / mm 2.	High	Sharpening and finishing of blades made of wear-resistant steels and hard alloys.
Diamond	Microhardness - from 5300 to 10000 kg / mm 2	Very high	Sharpening and finishing of blades made of hard wear-resistant alloys.

Ceramic bars

Basically, ceramic bars consist of grains of electrocorundum (aluminum oxide in the form of the so-called α-phase) or silicon carbide (technical name - carborundum; chemical composition SiC) and binder. Now on sale the most common bars are made in Germany, Poland and China. They are cheap (from 50 rubles), but finding a fine-grained bar is quite difficult (if not impossible). Until now, in the markets you can find products on which the proud inscription "Made in the USSR" flaunts. It is recommended to take a closer look at them. The fact is that modern market products are usually of very low quality. The grains are too different in size and break down catastrophically quickly due to the disgusting binder. The bars have to be leveled constantly, within half an hour after starting work. In principle, due to the cheapness of corundum bars, you can buy new ones instead of leveling them. But you can do this. Run the two bars regularly under running water.

Ceramic bars are offered by many companies that manufacture tools and sharpening devices. In general, it is possible that abrasive bars of a given shape are made for them by specialized firms engaged in the production of abrasive materials, it is even possible that they are the same. And they just use custom-made elements in their sharpeners, put their brand name on them and pack them in their original packaging. And, of course, there are different agreements between firms, following which they advise sharpening knives of their manufacture on sharpeners of one, not another manufacturer. Although in reality the sharpening result is determined by the skill of the grinder, and not the manufacturer of the selected tool (if, of course, this tool is of high quality).

The undoubted advantage of ceramic bars is that they have a huge resource and durability. Medium ceramics wear out very, very slowly, small ones practically do not wear out. The other side of the coin is that during operation, the bars very quickly become clogged with small particles of worn steel and lose their abrasive properties. Especially small ones. True, it is easy for them to return to working properties with the help of an ordinary kitchen pot cleaner or liquid soap mixed with fine sand, which is strongly advised to do after each use of such bars. Otherwise, they will grind the steel somehow, but form a harmful burr perfectly.

It should be remembered that when working with ceramic blocks it is highly advisable to use a lubricant: water or soapy water. Otherwise, the surface will quickly become covered with metal dust.

Abrasives from ceramics are simply molded (like a potter sculpts clay products), dried and then fired. And here (attention!) In the process of firing, some of the products lose their shape. Especially under-dried. Those on which defects are visible to the naked eye, of course, are immediately thrown away, because nothing more can be done with fired ceramics. But those on which a slight curvature can be seen, only by applying a ruler or two bars with the working surfaces to each other, can easily sell. If the amount of deflection does not exceed 0.5 mm, in the extreme case 1 mm for every 10 cm of the length of the bar, working on such a bar in practice will not harm the quality of sharpening. It is much worse if the bar is bent in a wave-like manner. Within the range of 1-1.5 mm on a 20-centimeter bar, this is also not so scary, but such an error may already somewhat worsen the quality of sharpening.

Japanese water stones

As a first approximation, these are abrasive grains of solid oxides or carbides deposited in a silicate (something like white brick) matrix. The question arises: well, our bars from the hardware store or some Chinese ones are not exactly the same? Yes, exactly the same. Only this in theory, but in practice the dog, as always, is buried in the little things. How uniform are the sizes of abrasive grains, how uniform is the composition and hardness of the matrix, etc. These stones are quite expensive, but cheaper than natural ones.

Their main difference from Western European and domestic counterparts is their softness, which is determined by the ratio of the pore volume to the volume of the bond and the abrasive grains themselves. Due to their softness, the bars grind off faster, constantly exposing new grains of abrasive, while the already worked grains form a suspension together with water on the surface of the bar. Therefore, Japanese water stones at higher wear rates provide consistently high performance with good surface finish. The use of small-grain stones provides a fairly quick finishing of the cutting edge to an almost perfect condition without polishing pastes, felt wheels and other accessories.

You cannot work dry on such stones. They should not only be sprinkled with water, but properly wetted. Japanese stones are pre-soaked in clean water. Deep plastic containers, preferably transparent, are suitable for this. It is better to have a separate container for each type of stones so that particles of coarse abrasive do not fall on smaller ones. The "soak" time is determined by the air bubbles emitted by the bar. Large, porous stones will bubble up, soaking up water for about 5 minutes. Smaller, medium-grained, saturated in 10-15 minutes. The most dense, fine-grained bars are "soaked" for 15-20 minutes.

Then the stone is placed on the holder. There are a great many of them - from purchased to homemade. The requirement for the holders is to ensure a stable position of the abrasive and exclude it from moving during work, since you will need both hands when sharpening. On fine-grained stones, before straightening, a slurry layer must be created, for which a block of fine-grained Nagura limestone is used. The stone is now ready to go.

During grinding and polishing, the amount of slurry will increase. It turns out to be pretty dirty work. You do not need to wash it off, just make sure that it does not thicken too much. The Japanese periodically moisturize it by dipping their fingertips into the water and shaking off the water from them onto a block. You can use a household spray bottle or disposable syringe - just be careful not to accidentally wash it off completely. If the blade begins to rust during sharpening, moistening can be done with mild soap and soda solutions. However, it is not recommended to use them when finishing and dressing the blade.

Try to use the entire area of ​​the bar. In the process of intensive metal removal when working with coarse-grained abrasive, watch out for its wear. As a rule, the middle part of the bar wears out as much as possible, which distorts the working plane and "fills" the cutting edge. There are a lot of means to combat this phenomenon. The Japanese themselves make special stones from hard wear-resistant grades of abrasive, with rows of parallel cuts on one side, at an angle of 45 degrees to the longitudinal axis of the bar, with the help of which the worn-out stone is leveled. For these purposes, you can also use coarse-grained waterproof sandpaper glued to the glass. The bar is placed on it with the worn side and moves in circular motions, reminiscent of the number "8", until the flat state is restored. You can use another, coarser stone. It is important that the restoration is carried out with water, after which the abrasive is thoroughly rinsed with a brush to remove the stuck particles of the larger abrasive.

The bars should be stored in individual containers - plastic or cardboard. Coarse and medium grain size (grain size up to 1000) - in water, especially if they are used regularly (once a week or more). Usually they are stored in a container closed with a lid, and disinfecting agents are added to the regularly changed water to prevent putrefactive processes. Rarely used bars are best dried after use. Fine-grained, on the contrary, dry thoroughly after each use. You cannot leave a wet block in the cold - frozen water can destroy it. Regular dressing of the stone will help reduce uneven wear and make it easier to maintain. At the same time, in order to prevent chipping of the edges of the stone during work, it is worth periodically, as it wears out, to direct on its edges a narrow chamfer at an angle of 45 degrees. It is recommended to glue the thinned bar with waterproof glue on an even piece of thick organic glass or wood - this will extend its life.

Working with Japanese water stones is an occupation that does not tolerate rush and fuss. However, if the sharpening process is perceived not as a tedious routine, but as a kind of meditation and ceremony, then it can not only provide an excellent result, practically unattainable by other means, but bring a state of peace and tranquility into the soul.

Diamond Bars

The king of abrasive materials is, of course, diamond, the hardest mineral in the world. Everyone knows about it. But not everyone knows that the unique cutting ability of a diamond is determined not only by this property. Compared to the hardness of even the hardest steel, there is no difference between the hardness of diamond and corundum. However, the nature of the crystal lattice gives the diamond abrasive grains a shape with sharper cutting edges. In addition, they do not change their shape during work. Simply put, don't be blunt. The fact is that every, even the smallest, diamond grain is always a single crystal, and it simply cannot have any other form than that determined by its crystal lattice. In extreme cases, it can crumble into even smaller crystals, but also mono and exactly the same shape.

A huge advantage of a diamond stone for sharpening knives is that its working surface never loses its correct, flat shape. The thickness of the diamond spraying is measured in fractions of a millimeter, therefore, we do not threaten any development of the surface of the bar. Even a completely "bald" diamond block that has completely lost its abrasive properties remains almost perfectly flat. A diamond block is fairly easy to make lightweight. Of course, this is not at all necessary when we are talking about large bars intended for work at home or in a workshop, heavy ones are even more convenient to work with: they are more stable. And they are not fragile: from a blow that would crumble a natural or fake diamond to smithereens, the thin, plastic-reinforced, diamond-coated steel plate won't even bend.

Diamond abrasive grains are most often adhered to the steel surface using electrolytically deposited nickel, less commonly other metals such as copper. The technology of deposition of diamond (or corundum) abrasive powder on a steel surface using an epoxy compound is also used. This is how cheaper and less durable sharpening tools are made. You can work on a diamond tool, slightly moistening it with water, in extreme cases, you can dry it. One way or another, a good diamond block does not tend to get clogged with particles of the processed steel, and in order to clean it completely, it is enough to rinse it in water, in extreme cases, you can wipe it off with a dry cloth or even just with your palm. Another plus of diamond abrasives is that they erase steel very quickly, and this effectively reduces the working length of the bar by about one and a half times compared to ceramic or natural. Of course, the longer the bar, the easier the work will be and the better the result, so you shouldn't really save on the length of the bar, even the diamond bar should still be at least one and a half times longer than the sharpened blade. But it is still somehow possible to work on a short diamond bar, but on a natural stone of the same length it will be self-torture and mockery of the blade, and not work. However, very effective abrasion of steel can be counterproductive and can easily lead to fairly significant and difficult-to-repair blade damage in unsteady or inexperienced hands. Particularly dangerous in this sense are coarse diamond abrasives used to quickly and efficiently profile the cutting wedge of a severely dull or damaged blade.

The main disadvantage of diamond sharpening stones is, of course, the price. And although a huge amount of artificial diamonds is produced all over the world and about the same amount of diamond powder comes in the form of waste from the production of jewelry, nevertheless, the technology for the production of good, branded, diamond abrasives remains quite expensive. You should bypass cheap diamond bars, they literally go bald before our eyes! The production technology is theoretically the same, but again the dog is buried in such "little things" as quality. The quality of literally everything - the electroplating process that precipitates nickel, the purity of the nickel itself, the uniformity and repeatability of diamond powder granulation, etc. It may happen that as soon as you bring the "untimely bald" bar to the store where you bought it, you will be told: "Normal wear and tear, nothing fancy, no warranty covers this, just like the clutch disc or, say, the brake pads in a car. Consumables and that's it!" Or even better: "You ruined it yourself, you didn't have to press so hard when sharpening!"

And you really don't need to press hard in any case. Not for any abrasive, but especially for diamond. With strong pressure, you will break diamond crystals out of the relatively soft nickel layer. And then you will irrevocably ruin the expensive bar. You have to be especially careful during the first period of operation, when the diamond block is "rolled in", or, more correctly, rubbed in. It may seem to you that a new diamond stone grinds steel very aggressively, but it loses this aggressiveness with literally every sharpened knife. However, if you bought a really high quality bar, then take your time to carry it back to the store with claims. This is a normal phenomenon for all abrasives, only in diamond, designed specifically for manual sharpening, it is most noticeable. After sharpening 10-15 knives, your bar will reach its calculated condition and will work as it should for a long, long time. It's just that at first, abrasive grains that are somehow sticking out of it crumble, protruding strongly from the surface layer. It is they who give the bar abnormal aggressiveness, and precisely because they protrude strongly, which means they do not hold well. The difference between a branded and a cheap nameless bar is that the cheap one will go bald more or less evenly further and further until it is completely bald.

Natural bars

Natural abrasive bars are almost always more or less small quartz crystals connected by sedimentary rocks, something like petrified silt. There are actually a lot of natural stones suitable for use as abrasive materials, and they are found in all parts of the world.

French geologist R. Cordier named a group of rocks, consisting of fine-grained siliceous shale with abrasive properties, novaculites, which means razor stone. The name stuck, and - an unprecedented case in petrography - it spread to whole groups of whetstones of various mineral composition: to mica shale with garnet grains, porous chalcedony, clay shale with quartz and other rocks. They are united only by abrasive properties and fine-grained structure. Garnet abrasives have long been widely known in Europe. The best of them is the so-called "Belgian stone". It is a fine-grained muscovite schist containing extremely fine garnet grains. Clay shales with quartz from Thuringia - Thuringian slate, micaceous schists with quartz from New Hampshire and Vermont, chalcedony abrasive from Missouri (USA) - are also classified as novaculites. The most famous deposits of such abrasives are found in the USA (the so-called Arkansas stone) and in Belgium (the so-called Belgian blue stone). In Russia, some types of shale were used for finishing operations.

In the case of abrasive stones, one cannot say that natural is better than artificial. The size of abrasive crystals in a natural stone can fluctuate within a fairly wide range, as well as the hardness of the sedimentary rock holding them together - the matrix. Imagine a block that grinds differently in different places in length and width? And it is not so easy to find blocks from which it would be possible to cut homogeneous blocks by an industrial method. And it is also difficult to saw it. That is why bars based on natural stones are, as a rule, more expensive than artificial ones. And sharpening is often worse, almost always slower, and wear out faster. Of course, with a properly selected set of good natural bars, you can perfectly sharpen a blade even from very hard modern steel. But if the same effect can be achieved easier, faster and cheaper with the help of artificial abrasives, then you have to be a really big lover of everything natural in order to neglect the benefits.

Arkansas stone (or Arkansas) consists of the most common crystalline silica, that is, quartz. But Arkansas has a special structure. Firstly, it is the purest quartz rock - it contains 99.5% SiO 2. Even in rock crystal there are more impurities! Second, Arkansas is the finest-grained and most uniform breed. Finally, it has the strongest bonds between grains. This is due to the so-called implication structure: the jagged grain boundaries seem to grow into each other.

The world's only "Arkansas Stone" deposit in the Arkansas River Basin (one of the largest right tributaries of the Mississippi River). This is where the name of the stone comes from. At one time, the rock lay there in thick layers, but as a result of intensive development, the deposits were depleted.

The larger the grain of Arkansas and the greater the porosity, the less hard it is. Stone different varieties- hard, medium and soft - occurs in separate, often adjacent layers.

If someone decides to purchase a set of Arkansas stone bars, then the following rules should be followed. Buy at least three bars - soft, medium and hard. Soft stone contains relatively large quartz crystals, and its matrix has a porous, spongy structure. Therefore, it is easily (relatively, of course) erased, exposing the next "fresh" abrasive crystals. Such a stone grinds steel faster, but more roughly, it can be used to profile the cutting wedge of a very blunt blade. But the stone itself wears out frighteningly quickly, especially when you take into account its price. The middle stone has a denser and harder matrix, and the abrasive grains in it are smaller. On the middle stone, you can sharpen moderately dull blades, it leaves behind a smoother (cleaner) surface, it erases itself more slowly, but also erases steel correspondingly slower. Hard stone - it is solid, and contains the smallest crystals. On a hard stone, the blade is polished to a perfect razor sharpness. It is the most durable, but it also grinds steel very "gently". Superhard Arkansas stones are already art for the sake of art, for those who want to polish their blade to a mirror shine, which in practice just does not always make sense.

When buying, you should choose the longest bars possible precisely because natural stone wears out steel slowly and the same effect is achieved with a significantly greater number of passes than on an artificial bar. For sharpening most work, hunting and camping knives, the natural stone block is 20 cm (8 inches) long; this is the absolute minimum. For kitchen knives with long blades, especially those made from hard and durable modern stainless steel, an even longer natural stone block is needed. Working on a short bar can simply be extremely inconvenient and unproductive.

Be sure to purchase a light mineral oil along with the Arkansas stone blocks, which is most often sold with them (but not always). In no case should you work dry on a natural stone! Its porous working surface will very quickly become clogged with particles of steel, and it will be rather difficult to "refresh" it. And the oil is simply "squeezed" between the matrix of the stone and the particles of steel, separating them from each other as it separates a rusty nut from a bolt. Which, of course, does not mean at all that the stone with such correct use will never get clogged. On the contrary, after each sharpening, the stone must be thoroughly rinsed. hot water with soap and a stiff brush to remove abraded steel particles mixed with oil. And before the next sharpening, slightly moisten (it is not necessary that it drips) the stone with oil again. When you sharpen on natural stone, it is easy to get dirty up to your ears yourself and stain everything around with a nasty black mess of oil and particles of worn out steel. It is very difficult to wash it off later, and the stone itself is not easy to wash. And in no case should you use vegetable oil for this purpose! It will penetrate into the pores of the stone to an indefinite depth, where over time it will polymerize from contact with oxygen in the air (how drying oil will polymerize - this is also vegetable oil), and then your stone can be thrown away. For the same reason, never sharpen a dirty, greasy kitchen knife on natural stone - always wash it well before sharpening.

Another undoubted disadvantage of natural stones is their fragility.

The dignity advertised by manufacturers and sellers that they allegedly "sharpen, erasing a minimum of steel from the blade" is, excuse me, nonsense intended for naive rich buyers. How can you sharpen this without erasing? Or "a lot" to sharpen, "little" to erase? All sharpening is based precisely on the controlled erasure of steel from the blade in order to give it the desired shape, in contrast to the uncontrolled and random erasure when the knife is blunt.

When your bar develops from natural stone in your middle, you take a flat concrete slab more, pour it well with water and rub the working surface of your bar again until it is flat. Of course, you will work out as you should, but again, the less, the sooner you take it up and the less you "run" your bar. And when the surface is already flat, as you can see by applying a ruler, throw on this very plate a sheet of medium sandpaper, also better waterproof, and give your "renewed" bar a proper cleanliness of the working surface. And so on, until your block is erased to such small thickness that will just break, but it won't come too soon, even if you sharpen one or two knives every day.

Using abrasive paper

In this topic, it is more correct to mention an alternative to abrasive stones. There are many adherents of sharpening knives on abrasive paper. Of course, a sheet of skin will serve incomparably less than a bar, but when there is a desire to try abrasives of various grain sizes, it is easier to buy a sheet of skin for a test than a bar, especially since a bar with a very fine grain may not be found. However, look for a very fine skin (for example P2000) in shops with a power tool or building materials is also ineffective. It is better to immediately go to the website of the telephone directory "Yellow Pages" (allinform.ru) in the section "Abrasives, tools", choose your city (if you have not chosen yourself), and look for those who trade in retail for cash.

The abrasive paper must be waterproof. To sharpen knives, it is cut into long strips 4-8 cm wide, which are fixed on a flat surface, such as a piece of glass. You can fix it in different ways, the main thing is that the skin exactly repeats the flat surface. If the base of the skin is made of a polymer film, when wet it will stick to a smooth and even surface. The abrasive paper can be attached with double-sided tape. To avoid unevenness, the adhesive tape must be glued over the entire surface. Mechanical fastening can also be made. You should also take care of attaching the fixture to the table.

To sharpen chisels and planer knives, abrasive paper can not be cut, and its working area can be changed as the abrasive wears out.

When sharpening, the skin is sprayed with water or soapy water. The blade should be moved along the skin without pressure. After sharpening, the skin is washed and can be used more than once.

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This review continues my series of reviews of various knife sharpening bars. Today we will talk about a diamond bar from the Venevsky diamond plant for sharpeners of the Apex type.

As usual, the review is presented in text and video versions. The video is attached at the end of the review.

WHAT IS THIS
By themselves, Venev diamond stones are widely known and are popular among sharpeners. The Hansa has a large topic dedicated to them, they are mentioned in many topics related to sharpening.

But this format is new. Until now, Venev bars have been produced in the format for manual sharpening in three sizes:, and. Users of the Apex type sharpeners have adapted to sawing these blocks and using them in sharpeners. This procedure is quite doable at home, albeit with certain problems. True, a bar 200 mm long does not fit into a standard mount, so two options were used: either shorten the bar, or remove the mount from the guide, holding the bar with your hand. Bars with a length of 120mm have their own minus - shorter length. But all these difficulties paid off with the performance of the bars and their acceptable cost, especially given the fact that the bars are double-sided. From time to time, a regret-wish was expressed on the forums: "Oh, there would be forms especially for the sharpener!"

And then there were bars, created specifically for the sharpener, with the appropriate mounts and standard size 150X25. Hooray! Finally. But then a dilemma arose. It turned out that a sharpener bar costs about the same as a standard bar, and even more. You can buy the hero of the review for 1180 rubles or a bar 120X35 for 900 rubles or a bar 200X35 for 1132 rubles. And this despite the fact that standard bars are double-sided, i.e. these are two stones in one. This alignment led to the fact that people thoughtfully scratch their turnips and think what to prefer - the convenience of work or economy? There is no definite answer, everyone sets priorities for himself.

WHY
Today, there is a steady trend in the knife industry: hard steels are becoming more widespread. Moreover, the point is not only in hardness as such, but also in the fact that carbide-forming alloying additives are widely used, primarily vanadium.

Not so long ago, a person accustomed to sharpening a banal stainless steel was often confused by D2 or P6M5 and had to hear “this knife cannot be sharpened! The stone wears out, but at least henna for a knife! ”, But there is only a maximum of 2.1% vanadium. Today, people are unanimously turning up their noses from steels that are below S30V and a hardness below 59HRC, and S30V with its 4% vanadium is already considered an average steel, and vanadium monsters with 9% are no longer such a rarity.
In short, knives made from hard steels with a high vanadium content have already come to dominate and need to be sharpened somehow.

In principle, rumors about the impossibility of sharpening knives from such steels are greatly exaggerated. In most cases, they can be sharpened without the use of diamonds, the same S30V and M390 are perfectly fine sharpened with ordinary stones. But at the same time, sharpening of modern knives often turns into a problem, taking a lot of time and leading to severe wear of the bars. In general, if you need to regularly sharpen modern knives, alas, you cannot do without diamonds.
The review was posted on YouTube before the text review was written. And in the discussion under the video, one viewer has already complained that it is not possible to sharpen a vanadis knife with stones based on aluminum oxide - the bars simply slide along the blade without removing the metal. This is an illustration of the above.

ORDER
Everything is simple here. I ordered in an online store, received a confirmation of dispatch and a track number by mail, watched the travel of the parcel in Russia, received it in a couple of weeks. With shipment to Kazakhstan it cost 1326 rubles (even before the devaluation. Eh ...). In general, everything is fine and usual.

THEORETICAL ASPECTS
There are a lot of controversies and myths surrounding diamond bars.
There are two extremes:
1.Diamonds are the best abrasive out of all existing, everything else loses to them in all respects, except maybe the price, so you can buy diamond stones, and you will get the perfect tool for all situations.

2. Diamonds can only be used if you don't mind the knife. Yes, diamonds work very quickly, this cannot be taken away from them, but at the same time they work very roughly, creating a defective metal layer, leaving microdefects that go deep into the blade and lead to chips on the cutting edge. Sharpening with diamonds is very short-lived, there is no work hardening effect, etc. etc.

I do not pretend to be the ultimate truth, I will just express my subjective opinion. In my opinion, as usually happens, the truth is in the middle, and both extreme points of view are not unequivocally correct. Diamonds should not be absolutized or demonized. It is just a tool that is optimal in a certain situation and for a certain application, but not very good in another situation and / or application. It has its advantages and disadvantages that must be taken into account when choosing a sharpening tool.

First of all, it is wrong to talk about “diamonds in general”. Diamond powder caricatured in a lap, diamond powder in the form of a free grain on a lap, diamond paste on paper, a diamond bar with an electroplated bond, a diamond bar with an organic bond - these are all diamonds, but they work very, very differently.

Speaking specifically about diamond bars, they are different. In practice, the most common are two options: solid electroplated bonded bars and soft organic bonded bars. Venev diamonds are representatives of the second category.


Electroplated bars are a metal plate on which diamond crystals are fixed (usually with a nickel bond). Diamonds form a layer simply spread over the surface of the bar. This type of diamond is produced by many manufacturers - both Chinese, Edge Pro, and the Poltava plant. This technology is well illustrated by the diagram from the DMT website:


Diamond crystals are firmly fixed in the bond and protrude strongly above its surface.

Venev bars are made in a fundamentally different way. Here, diamond crystals are evenly distributed in the bond and form a layer with a thickness (on the bar from the survey) 3mm. Basically, this is the same as traditional sharpening stones - an abrasive powder distributed in a binder, only here diamond powder is used instead of silicon carbide or aluminum oxide powder.

How does this difference affect the properties of the bars? It has a very strong effect, so much so that it is not worth giving any generalized assessment of "diamond bars in general" to these bars.

Electroplated bars remove metal from the treated surface very quickly and very effectively. This is the merit of the rigid bond and strongly protruding diamonds, which act as cutters that cut deeply into the steel. In most cases, such a bar provides the fastest sharpening in comparison with other abrasives (although due to certain characteristics it can sometimes lose in speed). In any case, the assessment of diamond stones as the fastest and most effective abrasive belongs to this type of stones.
The downside is a couple of features.
First, it is clear that since diamond "cutters" cut metal very effectively and deeply, the marks they leave are very rough. Conversations about the very rough work of diamond bars refer, again, to them.
Secondly, if such a bar is curved, then it can only be straightened by bending the plate on which the diamonds are applied, and this will not always be possible, to put it mildly.
Thirdly, in the process of exploitation, the diamonds are gradually worked out, torn out of the bundle, and the bar literally becomes bald. As a result, the bar gradually loses its original efficiency and speed.
Fourthly, diamonds often protrude very unevenly above the bond surface, either as a result of insufficiently high quality workmanship immediately on a new bar, or as a result of uneven baldness. Individual diamonds sticking out will leave deeper risks, greater pressure and risk of flaws.

Bars on an organic bond are very similar in their properties to ordinary sharpening stones. Diamond crystals do not protrude much above the surface; they are embedded in a soft bond. Because of this, such a bar, by definition, cannot work as quickly and efficiently as an electroplated bar.
The downside of this is a couple of features:
Firstly, with an equal size of diamonds, a bar with an organic bond works much less roughly than a bar with an electroplated bond. The risks left behind are not that deep. Talk of ugly rough diamonds plowing the cutting edge mercilessly is largely outside the scope of this type of stone.
Secondly, such a block can be easily leveled.
Thirdly, it retains its properties during operation. When the top layer of diamonds is triggered, diamonds below it emerge from under it, and so on until all 3 millimeters of the diamond layer have been worked out. According to user reviews, with intensive (but correct) use, Venev diamonds last 5 years or more without problems.
Fourth, there is no problem with individual height-grinding diamonds. But another problem appears - diamonds can be unevenly distributed over the volume: in one place it is dense, in another empty.

If you look at the results of the comparison, you might get the impression that Venev diamonds are better than bars on an electroplated bond, because they have much more advantages. But this is not the case. I'm not trying to conclude that some are superior to others. They are simply DIFFERENT, each type has its own pros and cons that need to be taken into account.
Electroplated diamond bars are indispensable when you need to remove a large number of metal (remove damage, form leads, change the angle of the RK, etc.). And when peeling is performed, all their disadvantages fade into the background, paying off with performance. But if you need to ensure accurate metal removal, then they are rough. So both types of bars get along well in one set, are used at different stages of sharpening, and, if used wisely, do not lead to negative consequences for a knife.

Returning to the extreme points of view mentioned above. Are diamond stones the ideal sharpening tool for all types of knives and steels? No, they are not. For some knives and steels, they do not work well.
Is everything so bad that it is better not to sharpen knives with diamonds? No, with judicious use, the risk of negative effects can be eliminated or minimized.

INSPECTION
A bar arrived in a plain envelope

Inside there was a sales receipt and a bar in a leatherette case, traditional for the Venev factory.


The case, in principle, is nothing special. Velcro fastener is completely normal. The material of the cover itself is unlikely to impress with some amazing wear resistance. But the very presence of the cover is still a plus, since the bar is protected from any accidental blows.




Let's move on to the bar itself.
The first thing that catches your eye is the reverse side of the form. She looks just gorgeous. Well, really. The surface is as if covered with diamonds and shimmers and gleams when you tilt the bar. The lettering makes it easy to read and looks good in terms of aesthetics.




The original diamond bar Edge Pro looks very pale against the Venevian background.


The external design does not affect the functionality, but still creates a pleasant impression of the product. A little discord with this splendor of the facets of the blank, which have traces of rough processing. The plant would have to remove these traces, since they paid attention to the presentation of the bar.

Well, okay, the bar was not purchased in order to admire it. We inspect the work surface.




There is some kind of unevenness in coloring - somewhere lighter, somewhere darker. What is the reason, I do not know (after the first sharpening, the color became uniform).

If you look with the naked eye, shaking the bar, then the diamonds shining on the surface are clearly visible. I turned it this way and that, it seemed that the distribution of diamonds was quite uniform, I did not notice the difference between the different areas.

Looked under a microscope. It also seems that the bond is quite homogeneous, and the diamonds are evenly distributed.








I measure the bar. It turned out 150.6X25X3.1. There are deviations from the declared dimensions, but a thicker working layer is a plus, not a minus.
One of the most intriguing questions: "What about flatness?" They often complained about the traditional Venevsky bars for manual sharpening that they were crooked. V recent times they began to write that the quality had improved, but there were no reviews about the sharpener bars yet. So…


There is a slight saddle shape, but within the acceptable limits. I didn't even bother to align. The Edge Pro had a similar saddle shape.

Summing up, we can say that the workmanship is good, no obvious flaws were found.
EXPERIENCES OF WORK
Before talking about what results a stone gives when sharpening, I want to note one very pleasing feature of diamond stones. They deliver a minimum of hassle in terms of the sharpening procedure. Unlike water stones, soaking is not required, and so much dirt does not form during the sharpening process. Sharpening is easier and cleaner, less space is required.

The bar is easily cleaned of sludge, dries quickly after rinsing.

Now about the results.
For the sake of experiment, I tried a bar on different knives and steels - from a "pan" soft stainless steel type 40X13 and worse to a quick cut and powder with all sorts of intermediate options between them- like 8Cr13MOV, 440C, etc.

If you just make some general conclusion, then the bar works well, quickly and copes with all the steels that have been tried. We can say that it is quite universal and, in general, can be a single type (but different grain sizes will be needed) of a bar for different knives.

But there are also nuances.

The bar cuts soft kitchen stainless steel like plasticine. Sharpening happens very quickly, literally a few movements are required. The cutting edge under the microscope looks pretty decent, the risks fall evenly

All this is great, but I consider the use of Venev diamonds for such steels unjustified. Firstly, ordinary stones, including cheap Chinese ones, can easily cope with such steels. Secondly (and this is the main thing), such inferior steels wear out the bar more than hard ones. It seems to be a paradox, but in fact this is understandable: on hard steel, the diamond works like a cutter, cutting and scratching hard carbides, and in such inferior steel it sticks like in plasticine, and as a result, diamonds are simply torn out of the bond, which leads to rapid wear bar.
In general, it is pleasant to work on such steels with this bar, but too wasteful.

Steel-"simple", they are the same average, such as 440C, AUS8, 8Cr13MOV a bar sharpens easily and very quickly. On this group of steels, especially with low hardness and high toughness, there is still a risk of diamond tearing out of the bond, but not the same as on the previous group. The use of a Venev bar for such knives is, perhaps, generally justified, although it does not give any special advantages in comparison with conventional ones. abrasive stones... Lack of soaking and dirt - yes, it is more convenient to work. But in terms of speed, ordinary stones can compete with Venev's. At the same time, diamonds work, whatever one may say, coarser than ordinary stones. It should be understood that the softness and delicacy of Venev diamonds is quite relative. They work delicately against the background of electroplated bars, but the properties of diamonds as crystals have not gone anywhere. So I still prefer to sharpen thin knives at a small angle with other abrasives.

And, finally, the most interesting group steels for which, in fact, the bar was purchased - hard high-alloy powders and tooling. It is on them that the Venev bar fully reveals its merits.
If I say that the bar is eating these steels like crazy, it would be a gross exaggeration. This can be said only about galvanized diamond bars. The Venevsky block rather simply reliably removes the metal, allowing you to sharpen these knives in the same way as you usually sharpen knives from mid-range steels, and not curse because you crawl and crawl with a stone on a knife, and the result is not visible.

With the naked eye, of course, the risks are clearly distinguished:


In general, sharpening of hard alloy steel knives is the main niche for such bars, in my opinion. I do not want to say that the Venev diamonds have no alternative in this regard. Not at all. It is quite possible to pick up bars that, in a given situation, will cope with sharpening no worse or even better than Venev ones.
The main advantage of Venev's is that they are simultaneously combined versatility, speed of work, softness of work, durability, convenience of work. Alternative options they are more highly specialized, they surpass the Venev ones in some of the parameters, but lose in others (galvanic ones are faster, but coarser, silicon carbide on a soft bond works more delicately, but it has strong wear and a lot of dirt, etc.), and the Venev ones combine dignity in all these parameters at once.

ABOUT ACUTE AND GRAIN

To get acquainted with the new bars, the option with a grain size of 50/40 was chosen for two reasons:

Firstly, this block is a "workhorse", which bears the main load during sharpening, and if we take a block for a start, then the most popular one is better.

Secondly, it was interesting to check one point of view. Quite often, among sharpeners, the opinion is expressed that 50/40 is the optimal grain size for achieving "working sharpness" and that there is no point in bothering sharpening to a high degree of sharpness - this is a waste of time that has no practical sense. This is expressed specifically in relation to Venev diamonds. Sounds tempting. If you practice this approach, then sharpening is simplified to the limit. The 50/40 bar works quickly and allows not only sharpening, but also repairing minor damage, i.e. in fact, it can become generally the only bar from which sharpening begins, and on which it ends.

The cutting edge obtained as a result of sharpening by 50/40 is naturally quite "toothy", which is clearly visible in the photo under a microscope. How sharp it is is clearly visible in the video. Could this sharpness be considered optimal? Everyone decides for himself. In principle, yes, the knife is quite sharp, it allows you to shave hair from the forearm, etc. But I would not consider such a sharpening optimal for all applications of the knife. This sharpening is good when you need to cut some ropes, tarpaulin, meat and other similar materials - it cuts very aggressively, "with a crunch." But if you need to plan something, when you need increased durability of the RK, I will choose a thinner and more thorough sharpening and finishing.

OUTPUT
I will summarize for those who do not have time to read the entire review.

The workmanship of the bar (size correspondence, flatness, uniform distribution of diamonds in the bundle) is good.
-Impressions of the sharpening results are positive
- It is very convenient to work, since it is not required to soak, there are no problems with cleaning from sludge, there is no such amount of dirt as when using water stones.
-The main advantages are the combination of versatility, productivity, accuracy of work and durability in one bar.
-Although the bar is versatile, in my opinion, it is still better to use it for sharpening knives made of hard alloy steels, which are problematic to sharpen with traditional abrasives.

disadvantages
- no obvious shortcomings were revealed. But, perhaps, a rather high price can be noted, in connection with which the sharpener bar is experiencing internal competition from the hand sharpening bars of the same manufacturer. You have to choose: "economy or convenience?"
-Another factor is not a disadvantage, but rather a feature of Venev diamonds: the speed of work is moderate. It is normal, but it can deceive the expectations of those who have heard enough about the crazy speed of diamond stones.

QUESTIONS WITHOUT ANSWERS

Just in case, I clarify that all the above conclusions were made regarding one particular bar with a grain size of 50/40 with a concentration of 100%. To what extent they can be extended to other options, I do not yet know. This version of the bars is a novelty, and so far there are practically no reviews.

I myself have questions to which it would be interesting to get answers. Perhaps someone will tell you if he knows and / or has already bought it?

1. How consistent is the quality of new bars of different grain sizes? Previously, on small blocks there were problems with uneven distribution of diamonds in the bundle.
2. Has anyone compared bars with the same grain size but different diamond content (25/50/100%)?

3. What is the difference between the new versions of the bars and the old ones? I decided to purchase a range of coarse to fine bars and it turned out that there is a variety of bars on the market with a slightly different designation (letter designation Coarse, Medium, etc. and a different grit range - 60/40 instead of 50/40). Recently, even in their descriptions it was indicated that they have some kind of new improved bundle, but now I do not see this phrase. So how are these options really different and what to prefer?

I plan to buy +45 Add to favourites I liked the review +57 +104

Anyone who has ever tried to cook something on their own knows how annoying dull knives are. It is not difficult to save precious nerve cells; you just need to purchase a good sharpening block, for example, a diamond one. Our article will tell you how to choose it.

Diamond sharpening stones for knives - subtleties of choice

Among all the abrasive materials used to sharpen kitchen (and not only) cutting tools, diamonds occupy a special, honorable place. Thanks to their unique structure, they have a very high level of strength, which means they have a long service life. At the same time, such a block is almost not clogged with shavings - to completely clean it, it is enough to rinse it under running water or wipe it with a cloth. Sharpening with diamond stones is suitable for knives made of almost any material, from the usual stainless steel to ultra-modern ceramics. Although, of course, you will have to tinker with the latter for a long time. When choosing a diamond sharpener, you should pay attention to:

1. dimensions... For ease of use, the length of the bar should be at least 3-5 cm longer than the length of the largest knife.
2. Grain... The marking, which for domestic products includes several numbers separated by a line, will help to determine the degree of abrasiveness of diamond stones for sharpening knives. Ideally, the farm should have several sharpening stones with different grain sizes: for roughing (160/125, 200/160, 250/200), semi-finishing (100/80, 125/100) and final sharpening (40/28, 50/40, 63/50). But it is quite possible to do with one double-sided bar, the sides of which have different degrees of abrasiveness. For foreign-made bars, the grain size is indicated by one number from 200 to 1200, which is equal to the approximate number of grains per one inch of surface.

Today's review is dedicated to the sharpening stones of the Venevsky diamond plant, purchased from the online store of this very plant. More precisely, legally, it doesn’t seem to be exactly a shop of the factory itself, but let's say the factory is an affiliate

As usual, the review is in two versions - video and text. Video version at the end of the review.

I have done before. In that review, I tried to consider in detail the theoretical questions: what are the pros and cons of diamond abrasives, what types of diamond abrasives are, how they differ, why diamonds with galvanic bonds and Venev diamonds work differently, etc. In order not to duplicate reviews, I will not re-consider the same questions, so if you are interested in this whole theory, you can follow the link and watch the first review.
In a nutshell, I will only remind you that electroplated diamonds, such as DMT, EdgePro and many others, differ in that they work much faster and coarser than Venev ones, while Venev diamonds work softer, more delicate, if you like, and have a greater resource due to the thick diamond layer, plus amenable to renewal and leveling.
When I was just studying the topic of diamonds, it struck me that in the discussions they focused attention, they said not just "diamonds", namely "Venev diamonds", something in the spirit of "well, for that you need to take Venev diamonds." At that time I thought that some individuals were promoting the manufacturer in this way because of some selfish interest. When I figured it out, I realized that in fact the emphasis was made due to the fact that the Venev diamonds are technically different from the rest of the ones on the market, and for many discussions it is essential to indicate which diamonds were used to perform this or that operation. So this indication of the manufacturer is actually information about the type of tool, and the indication is important because in some cases this tool is good, in others it is not.
Now about today's review. Now I have collected the entire middle part of the line of abrasives of the Venevsky plant, except for the thinnest and most coarse ones. And the review will focus on these forms:




This kit allows you to fully sharpen the knife. I mean sharpening in the narrow sense of the word, i.e. sharpening the knife. The assortment of the plant includes even coarser abrasives for roughing-200/160 and 160/125. The fundamental difference between roughing is that at this stage the formation of the cutting edge is performed and (if necessary) the elimination of damage, such as chips, for example. Therefore, it is often said that peeling is actually a repair job, and not a sharpening of a knife.
And there are thinner bars for finishing - 3/2 and 1/0. By the time these bars are used, the sharpening has long been completed, the knife is already sharp. The main tasks of fine-tuning are to ensure that the cutting edge (hence the name) is brought to a predetermined state in order to ensure durability, etc. Increasing the sharpness during debugging is a side effect.
Roughing and finishing are not considered in this review. In my opinion, it is wrong to lump them together with sharpeners. First, it is wrong in terms of sharpening technique. And secondly, one might get the impression that all Venev diamonds, from the coarsest to the finest, have identical properties, and the assessment of one of them applies to the entire line. And this is fundamentally wrong, and later it will become clear why.
This middle part of the line forms a single set, which I consider in this review as a single set for the step-by-step implementation of a single task of sharpening a knife.

All forms in the survey have the same concentration of 100%.

Received goods
To begin with, about the presentation.
I won't talk about the packaging - it was packed securely, all the bars arrived safe and sound.
Forms are delivered in the already familiar leatherette cases, inside of which there is a passport for each bar.




I don't see any reason to talk about the covers in detail. Covers are like covers, the fact that they are is a plus, although I would not say that they were surprised by their quality or something like that. Well, now, as far as I know, the covers have become completely different. On the manufacturer's website, the bars are shown already with new covers.
The appearance of the bars is the same as the previously overlooked 50/40. And now the set looks like this for me:




More precisely, he looked when he arrived.
I will again praise the Vienna bars for appearance... They look just gorgeous, clearly readable inscriptions are very convenient.

Flatness.
But the bars are bought not to admire, but to work with them, so there is a much more interesting question: what do the bars have with flatness? On this point, there are many disputes and claims against the plant. I show it.


On all my bars, the saddle shape is visible with the naked eye. Moreover, the diamond layer has the same thickness throughout the entire bar (measured with a caliper), but the forms are folded- all as one.
In my opinion, this may indicate that some kind of deforming load occurs during the manufacturing process. For example, as a result of exposure to temperature. The organic bond, as far as I know, during manufacture provides for the effect high temperature, and it is possible that the blank can bend during heating / cooling. At least with unsuccessful heat treatment, this happens with knife blades. Well, okay, the plant's technologists must deal with this.
For us, as users, the condition of the final product is more important. I said that there is a debate about curvature. On the one hand, a representative of the plant, both in personal correspondence with me and in Internet discussions, assures that each bar is checked for flatness, and curved bars are necessarily rejected. Photographs of the equipment on which flatness is checked were also provided.




Once the bar has passed the Quality Control Department, it means that it corresponds to the TU and cannot be crooked.
But I believe my eyes. And with my eyes I see bent bars. It would be necessary to check the size of the gap with the help of probes, but a smart idea comes after. The bars are already aligned, so I can only say that by eye the curvature is clearly greater than stated by the plant. How this is combined with the assurances of the plant about passing the Quality Control Department, I do not know. Maybe the bars are already after passing the test, in particular from heating-cooling processes? In any case, there are fact-bars have a saddle.

You can also look under a microscope. And the 100/80 bar is interesting here because the diamonds are clearly visible.




I would like to draw your attention to a couple of points.
First, the shape of the diamonds is visible. Illustrations of this kind are used in various discussions of the merits and demerits of abrasives.

They are intended to show that diamonds are a super-abrasive with sharp edges, very effective cutting metal. Interestingly, these pictures are used by both supporters of diamonds, showing how wonderful they are, and opponents of diamonds, showing how terrible diamonds hopelessly spoil knives, leaving terrible cracks on their surface.
In reality, industrial diamonds do not at all look like gem-quality cut diamonds.


They are more similar in shape to an ordinary pebble picked up on the road.


Second, notice that the diamonds are sunk in different ways in the bundle. I recently, passing by the Khrushchev, suddenly noticed that its wall is a completely visual model, which can be used to explain the structure of the bar.


The upper part of the wall is, for us, conditionally the surface of the bar at low magnification, and the bottom is the same at high magnification. And on the left is 100% concentration, and on the right is a bar with 50% concentration.
And here you can see that some stones are heavily sunk and barely peek out of the wall, that is, bundles, while others are almost completely on the surface. Plus, all the stones are oriented differently - some are turned towards us with a flat part, others with a sharp edge. What am I doing this for? Besides, this feature can be misleading. When the possibilities of optics do not allow us to clearly see diamonds, we judge their presence and size by their brilliance. And here it is easy to misinterpret what you see. In one place the diamonds do not shine due to the orientation in the bundle, and in another place the diamond on the surface shines with a successfully rotated plane, and you might think that we are observing a large scatter, it may seem that some diamonds are large, others are small, and even that is empty then thick.
Consider this point when looking at pictures of thinner bars. What glitters is not an entire diamond.
In general, I have no complaints about the working layer. Well, in general, in terms of the quality of the supplied bars, the only problem is the curvature.

In work
Now about how these bars have shown themselves in work. The general takeaway is simple: All bars work well. The marking is not confused, each next bar works thinner than the previous one and effectively removes traces of its work. But as always, there are a lot of nuances.

The first example is Andrey Biryukov's knife made of M390 steel with a hardness of more than 60.




More precisely, this is the blade of Andrei Biryukov, which was later turned into a full-fledged knife by the efforts of my fellow countryman.
M390 is not a very difficult steel in terms of sharpening, but it is still quite suitable for an example within the framework of this review, since its chemical composition and hardness are very impressive, it is a much more complex steel than the fast-cut steel from the previous review, and it is well suited for that to clearly show why diamonds are needed when much cheaper abrasives are available.
So, the first bar 100/80 is about 180 grit according to the most common classification.
It worked without any problems. The bar easily and naturally gnaws at the M390, like kitchen stainless steel. As a result, we have supplies with clearly distinguishable risks.


Under a microscope, one can see that there are no deep lines clearly falling out of the general row.




There is no point in checking the sharpness at this stage, although the knife is already cutting the newspaper quite calmly

50/40 is about 360-320 grit
The risks have become thinner, they still fall evenly. The knife has become even sharper and already, in general, is able to shave hair from the forearm, although it does it roughly.




The main thing that pleases is the speed. After the last bar, it took just a few minutes to sharpen it with all the settings and preparation.

20/14 is about 800-1000 grit
Everything is the same as before, the knife has become even sharper, and the carts are more beautiful, and they already shine noticeably.

7/5 is approximately 2000-3000grit
Well, everything is clear here - the end result is clearly visible: the carts shine, the knife shaves, the risks are neat, the cutting edge is ugly shapeless teeth. In general, quite a good result, on which it is quite possible to stop.

In the end, what do I want to say about sharpening M390 and other similar steels? Venev's diamonds are sharpened as if it were some kind of completely trivial steel from those that are now a little arrogantly called simpletons. M390 grinds off like a stainless steel kitchen. The end result depends solely on your skill. If you know how to sharpen, then with Venev diamonds you can sharpen a fast cutter or powdered super steel to a good result. There are holivars on the Internet that the end result of diamond sharpening is worse, especially in terms of durability. I will not delve into this topic now, because, as the well-known daughter of an officer said, “not everything is so simple,” and if you delve into it, you will have to talk a lot about it, and the conclusions and recommendations will not be unambiguous, but depend on the situation. For now, I will remind you that all the knives that win the Championship of Russia in rope cutting are sharpened with Venev diamonds. This is significant, regardless of how you feel about cutting a rope. Igor Lukinov generally considers this type of abrasive to be the best. Again, you can discuss with him, but his opinion is worth mentioning, since he has a very rich practical experience.
In general, the result obtained by sharpening high-alloy powder steels is at least good. Well, the main advantage of Venev diamonds from my point of view is how the sharpening process is going. I mean two things.

First, Venev diamonds allow run dry, i.e. without soaking or using oil. How result - procedure sharpening becomes much easier and cleaner than using water workers, for example.
Secondly, for me it is very important resource and stability Venevsky bars. Usually the discussion of the merits of diamonds revolves around the speed of work. Yes, it is important. Yes, when using non-diamonds to sharpen powder monsters, the sharpening time can stretch to completely unacceptable values. But, in fairness, I must say that there are abrasives, for example, silicon carbide on a soft bond, which work on such steels no slower, or even faster than diamonds... But the speed is ensured by a very fast grain renewal and, as a result, by a very fast wear of the stone. In some cases, this means that you sharpen-sharpen and see how the stone literally melts before our eyes. There is still a lot of work, but the stone has already been worked out to a noticeable saddle, and we need to interrupt in order to trim it, that is, we have additional troubles. And at the end of the peeling, you watch with sadness how the stone has noticeably lost weight. And this is after one knife... I myself have not yet come across very epic examples, but I have met reviews from people who did not have enough Boride CS-HD stone to finish peeling a knife.
And this is where diamonds have a huge advantage, which I would like to emphasize. Even if they do not benefit significantly in speed, they will definitely benefit in durability. Buying diamonds, you understand that even in difficult cases they are not enough for a couple of monster knives, but for a very long time. In an amateur format, for years, perhaps even for many years.

And if we compare diamonds with each other, then organic-bonded diamonds, by which Venevskys are meant by default, have another advantage. The fact is that electroplated diamonds are gradually balding. Again, for example, show the wall of a house as a model.


Diamonds are gradually torn out of the bundle, like stones from a wall in the photo. For electroplated diamonds, this is an irreversible process. And that's bad. It turns out that lonely diamonds stick out here and there on the bald bar, which leads to very uneven work. But at the Venevskys under the bald top layer there are still millimeters of fresh diamonds that show through after the top is mined. That is, galvanic ones work worse and worse, and Venevsky ones are stable until they work up to the substrate itself. Well, Venevskies work slower than galvanic ones, but softer and more accurate.

Okay, everything is clear with super steels. What about simpler steels? After previous reviews, judging by the comments, some viewers got the impression that diamonds in general and Venevski diamonds in particular are not suitable for knives made of, let's say, ordinary steels, that is, steels of the 40X13 level, 420 family, 440C, etc.
No, it’s not like that. It's not that diamonds aren't good for sharpening such steels. It was about the fact that they most often redundant... For such steels, you can work without problems with stones made of aluminum oxide or silicon carbide, which are usually much cheaper than high-quality diamonds. Plus there are some specifics in how different abrasives affect steel and how steel affects abrasives. In short, if only such simple steels are to be sharpened, there is no urgent need to buy diamonds.
But this does not mean that diamonds cannot be used in such situations. For example, I will show the sharpening of this Victorinox.


He needs to remove the chip on the tip.


Actually, the job is spitting, and diamonds are completely optional here. Moreover, there is no need to use rough diamonds. But since he has successfully turned up on the arm, he will be a test subject.

So, stage one, we use Venev diamond 100/80. There was an angle of 30 degrees on the knife, they asked to increase it to 36, so there is less work for the diamond here than for a minute. It's literally a minute.


In general, as I said, there was no need to use a 100/80 diamond - it was to shoot sparrows from a cannon. It is simply indicative that a diamond cuts such steel as if it were plasticine.
The edge looks relatively good under a microscope. For me, by the way, this is a surprise.




I expected to have a deep plow approach and rough, uneven teeth on the cutting edge. It was interesting to take a look myself, since I usually don't use diamonds for such steels.

The second stage, Venevsky diamond 50/40. Again, a redundant option in our situation. It could well be missed. But I'll use it as an example.


If you did not display a neat edge to show the result of this stage, then after half a minute it would already be possible to move on to the next bar. The bar, again, cuts steel like plasticine and very quickly removes traces from 100/80.

Go ahead - 20/14. If I had not done a review, but simply sharpened this knife with Venev bars, I would probably start immediately from 20/14... He would also remove that chip instantly, and at the same time the total sharpening time would be less, since we skip two stages.
The view under the microscope does not require any special comments.

Well, we finish with the last bar from today's review - 7/5. I worked with them a little longer to play it safe, that is, not to leave the risks from the previous bars, not to leave a burr.
This is what the edge looks like under a microscope. Quite normal. There are no rough marks left, the teeth on the edge are fairly uniform.


That's it, the sharpening is over.

By and large, the knife was already sharp after 100/80, and in principle, even at that stage, one could even stop. The knife is not razor sharp, but cutting aggressively. Some people even like this aggressive sharpening. The problem is she's holding on not for long especially when working on something hard such as wood. Well, with each next bar, the knife became sharper, and the retention of sharpness was better. After 7/5 everything is fine, but from an aesthetic point of view, the inlets do not look very good, especially because of the clearly visible border on the inlet after going to a larger angle, so I refurbished them a little without going to the edge. It took another one and a half or two minutes.




What did I want to say with this example with Victorinox? In this situation, it was easy to do without Venev diamonds and use something simpler and cheaper. It’s not even possible, but it would be a more justified option. I here used Venevskie only for the sake of review. But on the other hand, the Venevskys made it possible to remove the chip and sharpen the knife in a matter of a few minutes, literally playfully. Is the end result not good enough? Last time I sharpened this knife with natural stones. If after a while I ask the owner of the knife if he noticed that this time the sharpening was done differently, then what do you think he will answer? He will say that he immediately noticed - this time something is wrong, the sharpening does not hold at all, the blade is damaged and in general everything is much worse than the last time? Nothing of the kind. With such a blind study, he will not distinguish between "diamond" sharpening from "non-diamond" - I have already checked this more than once.

conclusions
Okay, the review is already taking a long time, it's time to somehow summarize and evaluate these four bars. Yes, by the way, let me again focus on the fact that all conclusions and assessments relate to to these bars... I'm not talking about Venev abrasives "in general", but about the sharpener bars with a concentration of 100% having a grain size of 100/80, 50/40, 20/14 and 7/5. Why does it matter?
-First. In sharpening, it is customary to distinguish three main stages: roughing, sharpening and finishing. So, these four bars form a set that provides the actual sharpening stage. Coarser for roughing and more subtle for debugging - this is a topic for a separate conversation, since some of the points voiced here for scraping and debugging are irrelevant.
-Second. Concentration affects the properties of the bar. I've heard that Venev diamonds 100% and 25% work completely differently. So much so that it is sometimes possible to use bars of the same grain size, but of different concentration, together. I have heard, but I have no experience in this regard, so I speak specifically for 100% concentration.
-Third. Now, on the sharpening resources, one can find serious claims to the Venev diamonds. In general, by the way, in almost all spheres it happens that at first something is praised in unison, and then the mood changes, and the same product is scolded no less amicably. The situation is similar with Venev diamonds. There was a period when they were extolled. But if a person decides to look at fresh discussions, then he will find that they are harshly criticized and it may seem that the abrasive is generally useless - there are so many dissatisfied, continuous swearing
So, do not jump to conclusions from a cursory examination of the discussions. Claims are really being made against the Venevsky plant, and the plant admits that there is a problem. But there is one very important nuance. The problem has been identified on the thinnest bars and the cause is not yet clear. Initially, it was believed that it was due to the fact that boron carbide was used in the organic bond, which itself is a very effective abrasive by ce6e, and the size of boron carbide grains turned out to be larger than the size of the main abrasive, i.e. diamonds. Now the plant has stated that according to the results of their research, the problem is not boron carbide, but what exactly is not clear.
Now the Venevsky plant is experimenting with bundles, trying to make thin bars, devoid of this problem.
But I would like to emphasize that this problem it does not matter to those bars that were on review today.
Again, the problem of flatness of the bars is less relevant for these bars for sharpening systems, but more relevant in the case of bars for manual sharpening.

In general, I will repeat. It is not worth giving any generalized assessment to Venev diamonds "in general" and transferring claims to finishing stones 1/0 for the entire line. Or after reading about the bending of the "screw" of the bars for manual sharpening, think that this is found on the bars for sharpeners. I have no complaints about the sharpening bars reviewed today. No not like this. I have complaints about the curvature, which I have already mentioned. But in terms of work I really like them, and I consider them extremely useful acquisition for me and for the sake of this I am ready to put up with non-flatness.
I will not speak for the rest of the plant's products, so as not to be accused of being superior, but with a clear conscience I can say about this part of their line that I like it and suit me. I wrote about the shortcomings - decide for yourself how critical they will be for you

This could be finished, but experience shows that some scroll to the end of the review and look for direct clear advice: "Just say - buy or not buy such bars?"
The short answer for those viewers would be:
« -If you have to regularly sharpen knives made of complex steels such as high-speed cuts and powder super steels, then I highly recommend purchasing a set of Venev bars from 100/80 to 7/5. There really is no worthy alternative to them in this category - this is not praising the manufacturer, this is an objective situation on the market.
-If you do not know what you need to sharpen and you want to have a universal set that is guaranteed to cope with any knife and will allow you to sharpen it quickly and without problems, I also recommend purchasing such a set. He may become the only one. Everything will be fine until you climb to read the forums, and then you can lose peace and sleep because of doubts about the influence of diamonds on the resource and durability of the knife :).
“But if you know for sure that you will only sharpen knives made of ordinary steel, simple-minded, then I see no reason to take diamonds - this is unjustified either financially or technologically.”

It is significant that in the same hanza, if a person is forced to often or even more predominantly sharpen knives made of wear-resistant steels, and especially if he has to do this as quickly as possible and get guaranteed result, he becomes an ardent supporter of Venev diamonds and often writes that this is the only abrasive that he needs (Igor Lukinov, Alexander, etc.). If a person sharpens mainly Japanese kitchen knives or razors, then he usually gravitates towards natural stones.

Here is the conclusion.
As for me personally, I am not a fan or an opponent of diamonds. I do not participate in disputes "diamonds against natural stones". I have diamonds on an electroplated bond, there are Venev diamonds on an organic bond, there are synthetic stones, ceramics, and natural abrasives. And they all get along well with each other, complement each other and no one ousted anyone.

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 Rockwell units). 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.