Reading time:
- Tips when choosing a whetstone for sharpening
- Sharpening Japanese knives
Sharpening knives is an inevitable process for any person. Despite the routine of this procedure, many not only do not know how to sharpen a knife correctly, but also pass on their “experience” to friends and acquaintances. There is an opinion that the correct sharpening of knives is relevant only for blades made of expensive steels, and a simple kitchen knife can be sharpened with a simple household sharpener for 200-300 rubles. In fact, any knife can be sharpened to a razor sharpness, just on a knife with poor steel, such sharpening will last no more than five minutes.
Manual sharpening of knives is a rather lengthy procedure, which includes the use of natural abrasive stones and diamond bars. In order for the knife to shave the hair on the hand, it is necessary to “finish” it on the skin, using the GOI paste of various numbers.
Choosing whetstones for sharpening
Grinding bars for manual sharpening of knives can be divided into four large groups, depending on the material used in their manufacture:
- Ceramic whetstones;
- Diamond stones;
- Natural stones of natural origin;
- Japanese water stones.
Ceramic knife sharpeners are the most affordable way sharpen your kitchen knives. It is with ceramic bars that the shelves of hardware stores and markets are filled. They are of several types. The most common is the "boat" bar. As a rule, it is very rough and is only suitable for rough sharpening or for changing the sharpening angles of a knife. Often there are bars from Poland, having two sides, with a rough and smooth surface. This is the best budget choice. If the bar is worn out, it is not a pity to throw it away and replace it with a new one.
Diamond stones are rarely used in professional knife sharpening. The sharpening process itself when using diamond bars is more complicated, and the cutting edge quickly becomes dull. Diamonds often leave deep scratches on the cutting edge and "eat" too much metal when sharpened.
Natural knife sharpening stones and Japanese water stones are the best sharpening stones for knives. The big disadvantage is their high price, often you have to order them from abroad.
The first criterion that you should pay attention to when choosing is the size of the bar. Its length should exceed the length of the knife blade by 1.5-2 times. The surface of the do-it-yourself knife sharpening bar should be smooth, without chips or cracks. If the stone is damaged, it is better to refuse the purchase.
For sharpening kitchen knives, a ceramic double-sided whetstone, or several bars of different grain sizes, made in the USSR, is suitable. No matter how they scolded the Soviet industry, grindstones in the USSR were made strictly according to GOST. Unfortunately, now such bars can only be found at flea markets.
If your task is not just sharpening kitchen knives, but you want to sharpen hunting or tourist knives to the state of a razor, then purchase GOI paste for finishing polishing the cutting edge.
Choice of grindstone grit
Grinding stones are usually divided into three categories:
- Rough grit;
- Medium grit;
- Fine graininess.
Not everyone knows that in addition to this, they are separated like sandpaper by the number of abrasive grains per conventional unit of area. The bars start at 100 and end at about 15,000.
Usually, when sharpening, bars of 600-800 units are used. To polish the edges, marking bars 1500-2000 are used. Bars over 2000 are used only by professionals and are rarely available for sale.
Step by step instructions for sharpening a knife
Before you start sharpening a knife, you need to understand a few rules for yourself:
- The angle of sharpening the knife must be strictly maintained;
- Do not press hard on the knife when sharpening, it will not sharpen faster, but the grindstone can be damaged;
- Sharpening stones should be washed with water to remove metal dust.
If you are trying to sharpen a knife for the first time, do not practice on expensive models, take a simple kitchen knife and bring it to a razor sharpness.
- First of all, you need to wash the bar with water and soapy water or dishwashing detergent;
- The second stage is the preparation of the workplace. To do this, a straight board is placed on the table, on which a grindstone is installed. Everyone chooses the position of the bar according to their feelings of convenience;
- Before you start sharpening, you need to choose at what angle you want to sharpen the blade. It should be remembered that for fine work, the sharpening angle should be about 20 degrees. For a utility knife, 30-40 degrees is also suitable. The choice of sharpening angle directly depends on the quality of the steel on the knife blade. Higher quality steel is able to keep fine sharpening for a long time. Sharpening cheap kitchen knives at a small angle is impractical;
- The essence of setting the correct angle of the blade is that the cutting edge is perpendicular to the movement of the knife along the whetstone. If the angle of the knife before sharpening suits you, it is not difficult to withstand it, the cutting edge simply presses against the bar with its entire surface. To change the sharpening angle, it is better to use special devices to hold the sharpening angle. They can be purchased at specialized knife stores or made by yourself;
- Having fixed the blade at the desired angle, we begin to slide the blade along the bar away from us. The blade is sharpened until a “burr” appears along the entire length of the cutting edge. When it appears, you can proceed to sharpening the other side of the knife. The dust that appears during sharpening must be periodically washed off under running water;
- After sharpening on a coarse abrasive, you can proceed to fine-tuning on a smaller stone. The procedure for such fine-tuning is no different from sharpening on a coarse grindstone. If you have several stones with a finer grit, continue sharpening, changing them from smaller to larger;
- For a kitchen knife, such sharpening will be enough, it will thinly cut a tomato and paper. If you want to achieve a razor sharpening of the blade, you should grind the RK (cutting edge) on the skin with GOI paste;
Bringing the cutting edge to razor sharpness
For “finishing the RK, they use a special GOI polishing paste, developed back in the days of the USSR by the State Optical Institute. The paste is spread on a piece of leather, which is preferably attached to a wooden block, the size of a standard whetstone. The peculiarity of polishing on GOI paste is that the knife blade must be polished with movements towards itself.
Sharpening Japanese knives
Sharpening of Japanese knives takes place according to a special scheme, since the blades of Japanese knives have a geometry different from others and one-sided sharpening. This geometry results in products not sticking to the knife blade.
Japanese blades are sharpened with the same abrasives as other types of knives, only they are sharpened on one side, until a burr appears. When it appears, the blade is flipped to the other side and the burr is removed with a few strokes. After that, the whetstone is replaced with a finer grit stone, and the procedure is repeated.
Household manual knife sharpeners
There are many small kitchen sharpeners out there that the manufacturer claims can sharpen a knife perfectly in one minute. In fact, these sharpeners can only be recommended to those who want to get rid of a knife in short time. These sharpeners “eat up” a large amount of metal, and soon the knife becomes thin and unsuitable for further use.
There are excellent knife sharpeners that not only can sharpen your knife to razor sharpness, but also make it easy to maintain or even change the blade's sharpening angle. These are systems like Edge Pro Apex or Lanski. A knife sharpening machine is quite expensive, about 6,000 rubles.
There are also analogues of the Chinese company Ganzo, which are half the price. The machine for sharpening knives of this manufacturer has proven itself quite well.
Common mistakes when sharpening knives
People who are not experts in the field of sharpening knives often make gross mistakes in this process:
- Having bought one first bar that came across, they believe that this is enough for a complete sharpening. In fact, a knife sharpening set should at least include several bars of different grain sizes;
- Knife missing. During sharpening, a lot of small burrs form on the cutting edge of the knife, which can give the feeling that the knife is sharpened. Such burrs quickly break off in the process of working with a knife, and it has to be re-sharpened. In order to avoid such a situation, it is necessary to carefully inspect the RK during the sharpening process;
- Some start sharpening without even cleaning the knife from dirt and grease, after seeing how professional chefs adjust their knives with moussat during the cooking process. It must be remembered that mussat is intended only for straightening the cutting edge, it does not sharpen the knife blade;
- Do not strongly press the knife to the bar during sharpening, this will only spoil the grindstone;
- Wrong sharpening angle. It must be remembered that too large a sharpening angle will not allow your knife to cut food thinly, and with a small sharpening angle, the blade will quickly “sit down” on solid foods.
When sharpening, just follow these simple rules, and you will succeed.
Device for sharpening knives with your own hands
If someone is not satisfied with the high price of a branded tool for sharpening knives, then you can do the installation yourself. The advantage of self-production is that you can make a knife sharpening kit according to your wishes, changing the design in any direction.
To start manufacturing work, you need to find a suitable drawing on the Internet. Usually homemade sharpeners are of two types:
- A simple Lanski type sharpener;
- Homemade sharpener, similar to the model from Edge Pro Apex.
It is up to you to decide which model to copy, just remember that the first option is easier to manufacture, but less convenient to use. A set for sharpening knives of the second type is technically more difficult to make, but it is much more convenient to work on it. We will consider how to make a simpler version in more detail.
Making a Lanski type sharpener
To make a Lanski type sharpener, you will need whetstones of different grain sizes, a piece of thick Plexiglas, from which we will cut out holders for stones, an aluminum corner, a thin steel bar and an aluminum profile.
To begin with, blanks are cut out of plexiglass for sticking abrasive stones. They should be slightly longer than the whetstones, as there are still holes to be drilled in them in order to insert a rod there. A bar pre-curved with the letter “G” is inserted into the drilled holes and fixed with a fixing bolt.
From the aluminum profile and the corner, you need to cut several blanks in order to then make a clamping system for the knife from them. At the top assembled structure do not forget to drill several holes for different sharpening angles, similar to the Lanski system.
Do not forget about making a rack to secure the entire structure in a fixed position. You can do without it, but it will create great inconvenience in the work.
Camping knife sharpening kit
Naturally, you won’t be able to take a full-fledged knife sharpening kit with you on a hike, but it’s advisable to put a double-sided stone and a bar with stretched skin in a backpack. Let the steel on your knife have outstanding characteristics, no one is immune from potholes and jamming of the cutting edge. It will be problematic to sharpen a damask knife or a powder steel knife, so take a small carbon steel knife just in case, it won’t take up much space, but it will help you out if the main knife fails. Carbon steel has a very aggressive cut and can be easily sharpened on a simple whetstone in a couple of minutes. At the same time, such knives hold sharpening quite well. The only negative is the lack of corrosion resistance of such steel.
It is not difficult to sharpen a knife correctly, you just need to follow the advice of professionals and have the necessary set of sharpening accessories. Everyone can choose the composition of this set for himself, taking into account his vision of the sharpness of the knife.
All whetstones, or whetstones are divided into 3 main large groups.
1. Ceramic bars. Grains of electrocorundum or silicon carbide act as an abrasive. Ceramic grains crumble quickly enough, the bars themselves become clogged with small particles of steel and lose their properties, so you should regularly wash them with soapy water to make them last longer. Such bars are the most affordable way if you just need to sharpen a kitchen knife. They are inexpensive, therefore, even if they fail, it will not be a pity to replace them. But sharpening a very blunt knife with a ceramic bar is extremely difficult.
2. Diamond bars. Raw materials are artificially grown diamonds. Each abrasive grain has a very sharp edge and is not destroyed during operation. Therefore, diamond bars do not dull and do not change their flat shape over time. And besides, they are not clogged with waste particles. When using diamond stones, you should remember: the grinding of the metal is very intensive, scratches may remain on the cutting edge. Therefore, in the wrong hands, this fine sharpening tool can cause damage to the cutting edge.
The technology for the production of diamond abrasives is quite expensive, and the cost of the materials themselves too. Therefore, a real diamond bar cannot be cheap. But it will last for an incredibly long time.
3. Japanese water stones. From the name it is immediately clear that the birthplace of origin is Japan and for work they need to be moistened with water. The last factor plays a decisive role. When wetted, a finely abrasive suspension is formed on the surface of the stone. It is the grinding material.
The main advantage of this method of sharpening is softness. Fine grains treat the metal gently, the homogeneous structure of the suspension makes sharpening better, and the cutting edge is resistant to blunting. With the help of good water stones, even difficult-to-sharpen blades made of hard high-carbon steel can be sharpened. Of course, the process itself takes time, but such a knife will serve for a long time. Japanese water stones are tools for real professionals, lovers of high quality knives.
When choosing bars, you should also pay attention to their graininess. It is she who determines the purpose of the stone. All stones, or bars, are divided into three categories:
1. Coarse grain stones. Used for repair work, removing traces of roughing, to prepare the blade for the main stage of sharpening.
2. medium grit stones. Serve for fine sharpening, finishing of the cutting edge.
3.Fine-grained bars. They are used when it is necessary to straighten and polish the surface of the blade.
A very dull knife cannot be fully returned to working condition with one bar. There is a rule: the knife should be sharpened from a coarse-grained bar to a fine one. Therefore, if you like good sharp knives, one grindstone is indispensable.
And, of course, one cannot but mention the importance of the length of the bar. To obtain a good result, if you work in stationary conditions, it is advisable to take bars whose length exceeds the length of the blade. Small whetstones are good for field conditions, for quick dressing of a knife during work.
Of course, you can sharpen the knife on an electric or mechanical knife sharpener. But the best, most sparing result will be only with manual sharpening, using whetstones.
"But who now sharpens on grinding bars?" - another reader will chuckle. The fact is that grinding at high speed, for example, on a high-speed grinding wheel, causes a strong heating of the material being processed, which in our case is fraught with uncontrolled and undesirable spontaneous release of the hardened blade, or at least part of the cutting edge of the blade. A thin strip of steel heats up instantly, the periodic dipping of the processed blade into water cannot prevent this. Therefore, never sharpen knives - whether homegrown or branded - on a high-speed grinding wheel, most likely, you will ruin the blade forever! It turns out that the quality indicators of a hand-sharpened blade are capable of far surpassing the parameters of its counterpart, brought to the average consumer level by factory automated means.
Each sharpening bar consists of two mechanically mixed fractions: abrasive grains-crystals - a material much harder than the material being processed (in our case, steel), and a matrix of softer material that holds the abrasive grains in a given shape, although the same bar.
The hardness of the matrix is usually commensurate with the hardness of the material being processed, sometimes even slightly less. Properly chosen hardness of the matrix allows it to be erased during operation, exposing more and more abrasive grains from deep layers, while the old ones, with already worn, blunted cutting edges, crumble out of the bar. In other words, by erasing steel, the abrasive bar is erased and worn out, and this is the normal process of its operation. 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 the grains out of the too soft matrix. In addition, as a result of self-erasing, the bar will quickly lose the desired shape of the contact surface with the processed material. Processing will then not be accurate. A matrix is, as a rule, something ceramic, from the simplest baked clay to varieties of technical faience.
The abrasive is characterized by the uniformity of the size of the abrasive crystals-grains. If the grains are not the same in size, then 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 together more or less evenly, 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, so the grain size is an interval characteristic. A certain difference lies in the shape of the abrasive grains of 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 a good result, but I want 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 reach $50-$100 or more. Start with ordinary "boats" and remember that the abrasive itself, even the best, is just a bar without your skills.
It is recommended that the block be at least as long as the blade being sharpened. And it's 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 reasonable money). 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), there is a high probability of meeting bars of a domestic manufacturer, moreover, made in the USSR.
2 - type: BP - rectangular bar;
3 - bar size: 25x16x150;
5 - granularity: 18 - 200...160 microns;
8 - structure (degree of convergence of abrasive grains): 8;
10 - accuracy class: B;
1 - emblem of the manufacturer;
3 - granularity: 6 - 80...63 microns;
5 - hardness of the abrasive tool: CT1 - medium-hard degree of hardness;
6 - structure (degrees of convergence of abrasive grains): 8;
7 - bundle: K - ceramic;
8 - accuracy class: A;
9 - the standard that the bar satisfies: GOST 2456-82;
10 - type: BKv - square bar;
11 - bar size: 20x150.
1 - emblem of the manufacturer;
2 - abrasive material: 64C - green silicon carbide;
3 - granularity: M28 - 28...20 microns;
4 - the minimum percentage of the main fraction: P - increased;
5 - type: BP - rectangular bar;
6 - bar size: 25.16.150 - 25x16x150;
7 - hardness of the abrasive tool: CT2 - medium-hard degree of hardness;
8 - structure (degree of convergence of abrasive grains): 10;
9 - bundle: K - ceramic;
10 - the document which satisfies the bar: TU 2-...;
11 - state quality mark of the USSR.
1 - emblem of the manufacturer;
2 - type: BT - triangular bar;
3 - bar size: 16x150;
4 - abrasive material: 25A - white electrocorundum;
5 - granularity: 6 - 80...63 microns;
6 - the minimum percentage of the main fraction: P - increased;
7 - hardness of the abrasive tool: CT1 - medium-hard degree of 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 focus only on grain size - the main characteristic. There are several systems of standards for determining the grain dimension in abrasive materials:
FEPA (Federation of European Producers of Abrasives) - the standards of the Federation of European Producers of Abrasives, adopted in Europe, as well as by the largest producers of abrasives in Russia and the CIS countries, as well as in India, Turkey and South Africa. The grit designation for a flexible material, such as abrasive paper, and a hard or loose abrasive, such as an abrasive stone, is different - P220 and F220, respectively.
ANSI (American National Standards Institute) - 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 apply to abrasive materials.
Be prepared for the fact that stores often sell sharpening bars for knives, not only without detailed markings, as in the photo above, but even without specifying the grain size. Most likely, this is due to the large variation in the size of the abrasive grain, 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 skins, one can at least roughly determine the grain size of the bar.
Grit marking according to various standards
| USSR | FEPA | ANSI | JIS | Purpose | |||||||
| Designation according to GOST 3647-80 | Designation according to GOST 9206-80 (diamond powders) | Size, microns | Designation for abrasive materials, excluding materials with a flexible backing. | Average size, microns | Designation chenie for abrasive materials on a flexible basis. | Average size, microns | Designation reading | Average size, microns | Designation reading | Average size, microns | |
| F4 | 4890 | ||||||||||
| F5 | 4125 | ||||||||||
| F6 | 3460 | ||||||||||
| F7 | 2900 | ||||||||||
| 200 | 2500/2000 | 2500-2000 | F 8 | 2460 | Very rough work. Cleaning blanks, castings. | ||||||
| F10 | 2085 | ||||||||||
| 160 | 2000/1600 | 2000-1600 | F 12 | 1765 | P12 | 1815 | |||||
| 125 | 1600/1250 | 1600-1250 | F 14 | 1470 | P16 | 1324 | |||||
| 100 | 1250/1000 | 1250-1000 | F 16 | 1230 | |||||||
| F 20 | 1040 | ||||||||||
| 80 | 1000/800 | 1000-800 | F22 | 885 | P20 | 1000 | |||||
| 63 | 800/630 | 800-630 | F24 | 745 | P24 | 764 | 24 | 708 | Repair work associated with intensive metal removal: restoring and changing the shape and profile of the blade and the cutting edge itself. | ||
| 50 | 630/500 | 630-500 | F 30 | 625 | P30 | 642 | 30 | 632 | |||
| F 36 | 525 | P 36 | 538 | 36 | 530 | ||||||
| 40 | 500/400 | 500-400 | F 40 | 438 | P40 | 425 | 40 | 425 | |||
| 32 | 400/315 | 400-315 | F 46 | 370 | P50 | 336 | 50 | 348 | |||
| 25 | 315/250 | 315-250 | F 54 | 310 | 60 | 265 | |||||
| F 60 | 260 | P60 | 269 | ||||||||
| 20 | 250/200 | 250-200 | F 70 | 218 | P80 | 201 | |||||
| 16 | 200/160 | 200-160 | F 80 | 185 | P 100 | 162 | 80 | 190 | |||
| 12 | 160/125 | 160-125 | F 90 | 154 | 100 | 140 | Removal of traces of peeling 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 | J240 | 60 | |
| F 230 | 53 | P 280 | 52,2 | J280 | 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 the blade surface, fine sharpening and finishing 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 | J600 | 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 | J800 | 18 | |
| P 1200 | 15,3 | 600 | 16,0 | J1000 | 15,5 | ||||||
| M14 | 14/10 | 14-10 | F 500 | 12,8 | P 1500 | 12,6 | 800 | 12,6 | J 1200 | 13 | Cutting edge dressing, 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 | J2000 | 6,7 | |||
| J2500 | 5,5 | ||||||||||
| M5 | 5/3 | 5-3 | F 1000 | 4,5 | J 3000 | 4,0 | |||||
| 3/2 | 3-2 | F 1200 | 3,0 | J4000 | 3,0 | ||||||
| 2/1 | 2-1 | F 1500 | 2,0 | J6000 | 2,0 | ||||||
| F 2000 | 1,2 | J8000 | 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 bars
| abrasive material | Description | Abrasive ability | Purpose |
| Corundum | A 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, electrocorundum is distinguished as normal, white (with a high content of aluminum oxide), chromium (technical ruby), titanium (technical sapphire) and zircon. Microhardness - from 1900 to 2400 kg / mm 2. | Low | A wide range of tasks - roughing, grinding, sharpening and finishing blades made of carbon and tool steels. |
| Carborundum | Contains 97-99% silicon carbide SiC. They produce two main grades - a harder and more fragile green carborundum and a dark one. Microhardness - from 3300 to 3600 kg / mm 2. | Medium | |
| 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 blades made of hard wear-resistant alloys. |
Ceramic bars
Basically, ceramic bars consist of grains of electrocorundum (alumina in the form of the so-called α-phase) or silicon carbide (technical name - carborundum; chemical composition SiC) and a binder material. Now on sale most often there are bars 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 disastrously quickly crumble due to a disgusting binder. The bars have to be constantly leveled, already half an hour after the start of work. In principle, because of the cheapness, corundum bars can not be leveled, but new ones can be bought. But you can do it this way. Under running water, regularly grind the two bars one to the other.
Ceramic bars are offered by many companies that manufacture tools and sharpeners. In fact, it is possible that abrasive bars of a given shape are made for them by specialized companies engaged in the production of abrasive materials, it is even possible that they are the same. And they only use custom-made elements in their sharpeners, put their brand name on them and pack them in their branded packaging. And, of course, there are different agreements between firms, following which they advise sharpening their knives on sharpeners of one and not another manufacturer. Although in reality the result of sharpening is determined by the skill of the grinder, and not by the manufacturer of the selected tool (unless, of course, this tool is of high quality).
The undoubted advantage of ceramic bars is that they have a huge resource and wear resistance. Medium ceramics wear out very, very slowly, small ones practically do not wear out. The reverse side of the coin is that during operation, the bars are very quickly clogged with small particles of worn steel and lose their abrasive properties. Especially small ones. True, it is easy for them to restore working properties with the help of an ordinary kitchen pot cleaner or mixed with fine sand. liquid soap, which is strongly advised to do after each use of such bars. Otherwise, they will grind the steel somehow, but they will form a harmful burr perfectly.
It should be remembered that when working with ceramic bars, it is highly desirable to use a lubricant: water or soapy water. Otherwise, the surface is quickly clogged with metal dust.
Ceramic abrasives are simply molded (like a potter sculpts clay products), dried and then fired. And here (attention!) during the firing process, some of the products lose their shape. Especially undercooked ones. 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 working surfaces to each other can easily sell. If the deflection does not exceed 0.5 mm, in extreme cases 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 curved in waves. Within 1-1.5 mm on a 20-centimeter bar, this is also not so scary, but such an error can already somewhat worsen the quality of sharpening.
Japanese water stones
In the first approximation, these are abrasive grains of hard oxides or carbides deposited in a silicate (something like white brick) matrix. The question arises: what, our bars from the hardware store or some Chinese ones are not exactly the same? Yes, exactly the same. Only this is in theory, but in practice the dog, as always, is buried in trifles. How uniformly the sizes of abrasive grains are selected, how uniform the composition and hardness of the matrix, etc. are. These stones are quite expensive, but cheaper than natural ones.
Their main difference from Western European and domestic counterparts is softness, which is determined by the ratio of pore volume to the volume of the binder and the abrasive grains themselves. Due to their softness, the bars grind faster, constantly exposing new abrasive grains, while the already used grains form a suspension along 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 fine-grained stones provides a fairly quick finishing of the cutting edge to an almost perfect condition without polishing pastes, felt wheels and other accessories.
On such stones it is impossible to work dry. They should not just 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 stone so that particles of large abrasive do not fall on smaller ones. The "soaking" time is determined by the air bubbles that the bar releases. Large porous stones will release bubbles as they absorb water for about 5 minutes. Smaller, medium grain, saturated in 10-15 minutes. The most dense, fine-grained bars are "soaked" for 15-20 minutes.
Then the stone is installed on the holder. There are a great many of them - from purchased to home-made. The requirement for holders is to ensure a stable position of the abrasive and prevent its movement during operation, since you will need both hands when sharpening. On fine-grained stones, before dressing, a layer of suspension must be created, for which a block of fine-grained Nagura limestone is used. Now the stone is ready to go.
During grinding and polishing, the amount of slurry will increase. It turns out to be quite a dirty job. You don't need to rinse it off, just make sure it doesn't thicken too much. The Japanese periodically moisten it by dipping their fingertips into the water and shaking off the water onto the bar. You can use a household spray bottle or a disposable syringe - just try not to wash it off completely by accident. If the blade begins to rust during sharpening, wetting can be done with weak soap and soda solutions. However, it is not recommended to use them when finishing and straightening the blade.
Try to use the entire area of the bar. In the process of intensive metal removal when working with coarse-grained abrasive, monitor its wear. As a rule, the middle part of the bar wears out to the maximum, which distorts the working plane and “fills up” the cutting edge. There are quite a few ways to deal with 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 which they level the worn stone. For these purposes, you can also use coarse-grained waterproof sandpaper glued to the glass. The bar is laid on it with the worn side and moves in a circular motion, reminiscent of the number "8", until the flat state is restored. You can use another, coarser-grained stone. It is important that the recovery is done with water, after which the abrasive is thoroughly washed with a brush to remove stuck particles of a larger abrasive.
Store the bars should be in individual containers - plastic or cardboard. Coarse-grained and medium-grained (grain size up to 1000) - in water, especially if they are used regularly (once a week or more often). Usually they are stored in a container closed with a lid, and disinfectants are added to the composition of regularly changed water to prevent putrefactive processes. Rarely used bars are best dried after use. Fine-grained, on the contrary, are thoroughly dried after each use. You can not leave a wet bar in the cold - frozen water can destroy it. Regular dressing of the stone will help reduce uneven wear and make it easier to care for. At the same time, in order to prevent chipping of the edges of the stone during work, it is worth periodically, as it wears, to induce a narrow chamfer on its faces at an angle of 45 degrees. It is recommended to stick a 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 activity that does not tolerate haste 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 that is practically unattainable by other means, but also bring a state of peace and tranquility to the soul.
diamond bars
The king of abrasives is, of course, diamond, the hardest mineral in the world. Everyone knows about it. But not everyone knows that the unique cutting abilities of a diamond are 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 operation. In other words, don't be dumb. The fact is that each, even the smallest, diamond grain is always a single crystal, and it simply cannot have a different shape 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.
The great advantage of a diamond whetstone for sharpening knives is that its working surface never loses its correct, flat shape. The thickness of the diamond coating is measured in fractions of a millimeter, so we are not threatened by any development of the surface of the bar. Even a completely “bald” diamond bar that has completely lost its abrasive properties remains almost perfectly flat. A diamond bar is quite easy to make light. Of course, this is not at all necessary when it comes to large bars intended for work at home or in a workshop, it is even more convenient to work on heavy ones: they are more stable. And they are not fragile either: from a blow that would crush a natural or artificial stone to smithereens, a thin steel plate reinforced on a plastic base, coated with diamond powder, will not even bend.
Diamond abrasive grains are most often held on steel surface using electrolytically deposited nickel, less often - 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 by slightly moistening it with water, in extreme cases you can also dry it. One way or another, a good diamond bar does not tend to become clogged with particles of processed steel, and in order to clean it completely, it is enough to rinse it in water, in extreme cases, you can wipe it with a dry rag or even just with your palm. Another plus of diamond abrasives is that they erase steel very quickly, and this effectively allows you to reduce the working length of the bar by about one and a half times compared to ceramic or natural ones. 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 a diamond bar should still be at least one and a half times longer than the blade being sharpened. 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 backfire and easily lead to fairly significant and difficult to repair damage to the blade in unsteady or inexperienced hands. Especially dangerous in this sense are coarse-grained diamond abrasives used for fast and efficient profiling of the cutting wedge of a severely blunt 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, the technology for the production of good, branded, diamond abrasives remains quite expensive. You should bypass cheap diamond bars, they are literally going 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 nickel-depositing electroplating process, the purity of the nickel itself, the uniformity and repeatability of the granulation of the diamond powder, etc. It may happen that as soon as you bring an "untimely bald" bar to the store where you bought it, you will be told: “Normal wear, nothing special, no warranty on it, just like a clutch disc, or, say, brake pads in a car. Expendable materials and that's it!" Or even better: "You ruined it yourself, you shouldn't have pressed so hard when sharpening it!".
And you really don't need to press hard. Not for any abrasive, but for diamond in particular. With strong pressure, you will break out the diamond crystals from the relatively soft layer of nickel. And then you will irrevocably spoil the expensive bar. It is especially necessary to be careful during the first period of operation, when the diamond bar is "running in", or, more correctly, lapped. It may seem to you that the new diamond whetstone grinds steel very aggressively, but it loses this aggressiveness with literally every sharpened knife. However, if you bought a really high-quality bar, then do not rush 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 design condition and will work as it should for a long, long time. It's just that at first, abrasive grains are crumbling out of it, somehow holding on, strongly protruding from the surface layer. It is they who give the bar an abnormal aggressiveness, and precisely because they protrude strongly, which means they hold weakly. The difference between a branded and a cheap no-name bar is that the cheap one will more or less evenly go bald further and further until it is completely bald.
Natural bars
Natural abrasive bars are almost always more or less small quartz crystals bound 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.The French geologist R. Cordier called the group rocks, consisting of fine-grained siliceous slates with abrasive properties, novaculites, which in translation is a razor stone. The name stuck, and - a case unprecedented in petrography - spread to entire groups of whetstones of various mineral composition: on micaceous schists with garnet grains, porous chalcedony, argillaceous shales with quartz and other rocks. They are united only by abrasive properties and a 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 shales with quartz from New Hampshire and Vermont, and chalcedony abrasive from Missouri (USA) are also classified as novaculites. The most famous deposits of such abrasives are in the USA (the so-called Arkansas stone) and in Belgium (the so-called blue Belgian stone). In Russia, some varieties 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 natural stone can vary within fairly wide limits, as well as the hardness of the sedimentary rock that holds them together - the matrix. Can you imagine a bar that grinds differently in different places along the length and width? And it is not so easy to find blocks from which homogeneous bars could be sawn out in an industrial way. Yes, and it is also difficult to cut it. Therefore, bars based on natural stones are, as a rule, more expensive than artificial ones. And sharpening is often worse, almost always slower, and they 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 great 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 the structure of Arkansas is special. Firstly, this is the purest quartz rock - it contains 99.5% SiO 2. Even in rock crystal there are more impurities! Secondly, the Arkansas is the finest grained and most uniform breed. Finally, it has the strongest bonds between grains. This is explained by the so-called implication structure: jagged grain boundaries seem to grow into each other.
The world's only deposit of "Arkansas stone" in the Arkansas River basin (one of the largest right tributaries of the Mississippi River). Hence the name of the stone. Once upon a time, the rock lay there in thick layers, but as a result of intensive development, the deposits were depleted.
The larger the Arkansas grain and the greater the porosity, the lower its hardness. Stone of different grades - hard, medium and soft - lies in separate, often adjacent layers.
If someone decides to purchase a set of Arkansas stone bars, then you should adhere to the following rules. Buy at least three bars - soft (soft), medium (medium) and hard (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 following "fresh" abrasive crystals. Such a stone grinds steel faster, but more roughly, it can be used to profile the cutting wedge of a very dull blade. But the stone itself wears off terrifyingly quickly, especially when you take into account its price. The average stone has a denser and harder matrix, and the abrasive grains in it are smaller. On the middle stone, you can sharpen moderately blunt blades, it leaves behind a smoother (cleaner) surface, it erases itself more slowly, but steel erases correspondingly slower. Solid stone - it is solid, and contains the smallest crystals. On a hard stone, the blade is polished to an ideal, razor sharpness. It is the most durable, but it also grinds steel very "gently". Superhard Arkansas stones are already art for art's sake, for those who want to polish their blade to a mirror finish, which in practice just doesn't always make sense.
When buying, you should choose as long bars as possible, precisely because natural stone erases steel slowly and the same effect is achieved by a significantly larger number of passes than on an artificial bar. For sharpening most work, hunting and outdoor knives, the length of the natural stone bar is 20 cm (8 inches); this is the absolute minimum. For kitchen knives with long blades, especially those made of hard and wear-resistant modern stainless steel, an even longer natural stone bar is needed. Working on a short bar can simply be extremely inconvenient and inefficient.
Along with the bars of Arkansas stone, be sure to buy a light mineral oil, which is most often sold bundled with them (but not always). It is impossible to work dry on natural stone in any case! Its porous work surface will quickly become clogged with steel particles, and it will be quite difficult to “refresh” it. And the oil simply “squeezes” between the stone matrix and the steel particles, separating them from each other in the same way as separating a rusted nut from a bolt. Which, of course, does not mean at all that a stone with such correct use will never get dirty. On the contrary, after each sharpening, the stone must be thoroughly washed. hot water with soap and a stiff brush, specifically to remove bits of worn steel mixed with oil. And before the next sharpening, slightly moisten (it is not necessary that it drips) the stone with oil again. When sharpening on a 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 steel. It is very difficult to wash it off later, and it is not easy to wash the stone itself. And in no case should vegetable oil be used for this purpose! It will penetrate into the pores of the stone to an indefinite depth, where it polymerizes over time from contact with atmospheric oxygen (as drying oil polymerizes, 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 a 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 designed for naive rich buyers. How can it be sharpened without erasing? Or "a lot" to sharpen, "little" erasing? All sharpening, after all, is based precisely on the controlled erasing 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 blunted.
When your bar of natural stone is worked out in its middle, you take a flat concrete slab larger, pour it well with water and grind the working surface of your bar again to a flat shape. Of course, you will work out properly at the same time, but again, the less, the sooner you take it on and the less you “launch” your bar. And when the surface is already flat, as you can see by applying a ruler, throw a sheet of medium sandpaper on this very plate, also better waterproof, and give your "updated" bar the proper cleanliness of the working surface. And so on, until your block is worn down to such a thin thickness that it simply breaks, but this will not come too soon, even if you sharpen one or two knives daily.
Using abrasive paper
In this topic, it is more correct to mention an alternative to abrasive bars. 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 out 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, looking for a very small skin (for example, P2000) in stores selling power tools or building materials is also ineffective. It is better to immediately go to the website of the Yellow Pages telephone directory (allinform.ru) in the section "Abrasive materials, tools", select your city (if you haven't chosen it yourself), and look for those who sell retail for cash.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 attach it in different ways, the main thing is that the skin exactly repeats a flat surface. If the base of the skin is made of a polymer film, wetted, it will seem to stick to a smooth and even surface. Abrasive paper can be stuck with double-sided adhesive tape. To avoid unevenness adhesive tape must adhere to the entire surface. You can also make a mechanical fastening. You should also take care of attaching the device to the table.
For sharpening chisels and planer knives abrasive paper you can not cut, and change its working area 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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A sharp knife in the kitchen is the key to peace in the family. After all, stupid cutlery capable of causing irritation to the hostess, which will necessarily affect not only the cooking process and appearance dishes, but also on the mood of loved ones.
Of course, you can take the knife to the workshop, where it will be processed with high quality. But, firstly, it will take some time, and secondly, the head of the family may feel disadvantaged, having lost the opportunity to show his skills. Therefore, experts recommend purchasing at least one abrasive block for home use.
Classification
There are 5 types of abrasive stones for sharpening knives:
- ceramic;
- diamond;
- from water Japanese stone;
- from artificial water stone;
- from Arkansas stone.
Each of them has its own characteristics, which will be discussed below. In any case, the tool is usually presented in the form of a three-dimensional rectangle made of special stones or with a surface made of abrasive material.
Ceramics
Bars of this type are made from microscopic electrocorundum grains or silicon carbide. Their undoubted advantage is slow wear. Such bars will last a long time if used to straighten the blade.
A negative moment, experts call a rapid change in the grinding properties of the surface of the bar due to clogging of the gaps between the microparticles with metal shavings. Such stones require constant cleaning and the use of lubricating fluids.
To prolong their life, masters in the field of sharpening recommend periodically grinding the bars under running water. Good care will allow for a long time to edit home knives without visible material costs.
diamond bar
The surface of the bar consists of natural material or artificial chips, similar to diamonds in strength. There are two ways of coating a bar.
In the first case, small granules of a nickel alloy are, as it were, smeared over the working part of the tool. Due to the high degree of graininess of the bar, sharpening of the knife occurs at a high speed, but leaves visible scratches. And, besides, unlike ceramic samples, the surface of the tool itself is ground off without the possibility of further restoration.
In the second case, organic-based crystals are used, which reduces the number of scratches and increases the life of the bar.
This natural tool has its own rules of use. So, before use, experts recommend soaking the stones in water - each sample in a separate container - and waiting until they stop emitting bubbles. After that, they are taken out, fixed on a stand and proceed to sharpening. It is first made on a coarser bar, periodically wetting it with water, and then polished on a fine-grained one.
The complexity of working with natural stone, the high degree of wear and high cost do not contribute to the spread of such sharpening among the inhabitants. But through the use of Japanese water stone, you can sharpen any stubborn knife in a professional workshop.
artificial water stone
This material is slightly inferior to natural samples, but has the same degree of graininess over the entire structured surface, which greatly facilitates the turning process and reduces the cost of the material.
Despite the second place among water samples, these stones have proven themselves well in home use.
Arkansas stone
This most expensive tool for home use contains quartz particles. When working, it carries out minimal grinding of the surface, which ensures an excellent result.
The only drawback, experts call the need to use a specialized lubricant, without which the abrasive bar will deteriorate in the very first sharpening. Working without technical oil will lead to clogging of the surface with processing waste that cannot be removed from the pores by any means. As a result, an expensive tool will simply have to be thrown away.
Bar parameters
The quality of sharpening a knife depends not only on the material of the tool, but also on such indicators:
- forms;
- graininess;
- hardness.
Abrasive bars-boats are widely used. The shape of a regular rectangle is also quite popular, which, although easier to handle, slightly reduces the quality of processing.
The grit parameter determines the amount of metal removal. So, the most powerful removal of the working part of the knife provides a material with an indicator of 200 microns.
Different hardness is used for different sharpening. So, softer abrasives are used for roughing, and the hardest materials are used for final processing.
How to choose an instrument?
In order to sharpen a knife with high quality and hassle-free, you need to purchase right tool. The abrasive stone must meet the following conditions:
- be 2 times longer than a knife blade;
- not have chips and cracks on the surface;
- have the correct geometric shape.
It is better if there are several bars at home with varying degrees of graininess. To polish the cutting part of specialized knives after sharpening, it is necessary to use GOI paste.
How to sharpen
For the first time, even having a super bar made of high-quality abrasive material, it is recommended to sharpen the knife that you do not mind spoiling.
In addition, experts advise to adhere to a number of rules:
- Moisten the bar with water and grease with any detergent solution.
- Place the sharpening tool on a hard surface at an angle of 45° towards you.
- Give the desired angle of inclination of the knife so that the connection between the knife and the handle is outside the stone and perpendicular to its long part.
- Perform several slides away from you, and then 40 times towards you.
- Turn the knife to the bar with the opposite cutting side, and repeat the movements.
- Sliding to achieve the elimination of a burr, which is not always visible visually, but is determined by touch.
- If a double-sided abrasive bar is purchased, then finishing the knife is carried out by the second side with a smaller grain size. The same manipulation can be carried out with another tool or musat.
The sharpening procedure of the tool should be accompanied by periodic wetting in order to eliminate small metal debris. If you need a perfectly sharp device, then editing can be provided with a piece of leather treated with GOI paste. The movements of the leather device in this case should go in the direction from the cutting edge of the knife.
Sharpening bar analogues
Of course, buying abrasive bars is ideal for a good owner. In the absence of such, you can resort not only to the services of specialized workshops, but also to purchase special knife sharpeners:
The penultimate option, despite the high cost, leads to a quick grinding of the blade. Manual devices require the use of certain efforts. Specialized systems are expensive, but they allow you to give the correct shape and sharpening angle to the kitchen knife, as well as keep the cutlery in working order for a long time.
A few last words
There are a lot of people who find any reason not to do housework. This also applies to knife sharpening. And if a man does not have a soul for this, you should not purchase expensive stones or entire grinding systems. Enough to buy cheap hand fixture for emergency needs and make it a rule: carry knives to the workshop, and spend your free time on your favorite activities with your family.
For those who are not in the subject, so that there are no misunderstandings, I will explain the terms used:
Blade- The part of the knife that is not the handle. Usually made of steel or ceramic.
Butt- the back side of the blade, opposite the cutting side.
Descent- a narrowing going from the butt to the cutting part. For knives with a wedge-shaped section, the entire blade is made in the form of a descent. But for many knives, for example, for the Finn, the descent occupies only the 3rd part of the width of the blade, while the rest remains a flat plate.
cutting edge(edge, RK) - the edge of the knife, which is used for cutting.
Approach (chamfer)- sharpening going from the descent to the cutting edge. Typically, the approach completes the slopes, making the knife finally sharp (theoretically, knives are possible where the slopes end with a cutting edge without an approach). Almost always, the approach has some angle to the descent. If the knife is not altered, but simply sharpened, then it is the supply that is processed.
Microlead (microbevel)- the part of the inlet closer to the cutting edge, sharpened, in relation to the rest of the inlet, at a more obtuse angle. Micro-leads are sometimes made deliberately, usually with a finer abrasive, to increase the durability of the edge (so-called step). But sometimes they are the inevitable result of manual sharpening on a block without rigid fixation, as a result of which the lead is slightly rounded. Since, when finishing sharpening on thin bars, they try to keep the angle more carefully, after sharpening, the supply turns out to be a rough bar, gradually changing the angle and turning into a finer sharpening.
The presence of a micro-advance is not a necessary condition for good sharpness. Moreover, done incorrectly (usually due to the difficulty of controlling the angle) results in the knife becoming blunter than it was before the micro-advance was formed. The knife can cut well and for a long time. So, usually even an unsuccessful micro-advance does not spoil the sharpening. However, shaving starts worse, or stops shaving altogether.
Machine- usually electric machine for sharpening with a circle or tape. It is used in industry for the rapid formation of slopes (in the event that they are not obtained by forging) and a cutting edge. In everyday life, it can be used to quickly regrind a knife to a new angle and create new supplies. Some NOT craftsmen try to use the machine for other purposes and, instead of reworking or making a knife, they try to sharpen it. This leads to unnecessary removal of metal, as a result of which, after several such sharpenings, the knife is disfigured. At the same time, it is not possible to achieve good sharpness on the machine (unless, of course, you have a set of discs of the required grain size, which is never the case in reality). And, in fact, sharpening a knife on a machine, people simply make the knife unusable.
In addition, sharpening on the machine often leads to overheating of the metal, as a result of which the knife is quenched, becomes soft and quickly dulls, requiring frequent sharpening.
Lamellar broaching sharpener- plates of hard steel or ceramics directed towards each other, between which it is proposed to drive a knife, peeling off the plates. As a result of peeling, the edge of the knife becomes thinner, increasing sharpness. However, such a peeling destroys the structure of the metal on the knife, leaving deep grooves (when viewed under a microscope), and stretching the metal. As a result, the edge is not very stable, it quickly becomes dull, jammed, and crumbled. You have to sharpen often, spending extra time on it and killing the knife.
The longitudinal grooves left by the sharpener prepare the metal for a quick break.
As a result, the knife becomes dull quickly and requires new sharpening, and this increases wear and time costs.
Musat- similar to a round file. Metal pliers are designed to unfold the wrinkled edge on soft knives. It is impossible to sharpen a knife on a metal musat. For hard steel knives, metal musat is generally useless. Ceramic grinders are usually a round whetstone and allow you to both turn the edge and sharpen the knife. However, a good sharpening of a knife on them is an almost impossible task. Grinding bars of square section, about a centimeter thick, can be attributed to musat. It is inconvenient to sharpen on this hybrid, however, as on ceramic musate, you can expand the edge and sharpen the knife.
Since the edge can be turned not only with a metal rake, but also with the butt of another knife, and the rake is useless for hard steels, the practical value of musat tends to zero. To use musat or not is a matter of taste. But musat is convenient when there is no desire to wash the knife. You can’t fumble with a dirty knife on a grindstone - the stone will then have to be cleaned for a long time. And the musat is easily washed off. So, for butchers, when cutting carcasses, the presence of musat at hand will be convenient
There is a widespread misconception that musat is more careful with a knife than a grindstone, because it does not remove a lot of metal. But, firstly, you do not need to edit the knives with trimming stones, and secondly, loosening the edge in different sides, musat does not make it stronger. So, with the ability to use stones, the choice and the opportunity to wash the knife, musat becomes superfluous.
Sharpening system- a system for manually sharpening a knife, which allows you to do this while maintaining a constant sharpening angle. In this system, a file or whetstone walks along a guide. As a result, unlike sharpening by hand on a stone, in which the hand inevitably changes the angle, making the approach rounded, in the sharpening system the angle is always the same. As a result, peeling off the excess surface is excluded and, firstly, productivity increases noticeably, and secondly, the result looks more accurate.
Abrasive- the working part of the main grinding tools (bars, discs, sandpaper, ceramic musat). It can be presented in the form of a powder, mixed with something in the form of a paste (for example, GOI paste), cemented into a bar with some kind of binder, pasted on paper (metal plate, fabric). Abrasives are also part of natural grindstones. For example, many types of shale are sharpened by containing quartz crystals. Depending on the type of abrasive (albor, diamond, boron carbide, silicon carbide, chromium oxide, aluminum oxide, quartz, etc.), and the size of the crystal (grain), the abrasive properties of the tool vary.
Sharpening of knives and other tools begins with a coarse abrasive, gradually moving to a finer one. I think doubling or tripling the grain size is optimal. For example, after 200 grit, switch to 400 grit, then to 800 grit, etc. Everyone will decide for himself which sizes to use (for example, 240 => 500 => 1000, and possibly continue 2000 => 4000, etc. d.). It depends on what size you want to finish sharpening and what kind of abrasive is available. I decided that enough sharpness to stop at was achieved with 800 grit. For kitchen knives that are constantly subjected to cruel tests, such as cutting on ceramic plates, there is no point in fiddling with finer sharpening, as you can spend a lot of time sharpening, then cut a tomato on a plate and end up with a knife blunted on a plate. So, for universal kitchen knives, I determined sufficient sharpness obtained on a stone of 800 grit. And the rest of the dimensions were determined from this representation, dividing (for preliminary sharpening) or multiplying (for finer finishing) the values by 2 and choosing from the available assortment the values \u200b\u200bthat are closest to those obtained by division. It is the size of the step that matters. For example, a one and a half step will take quite a long time to level the furrows left in the previous step, and then the same amount of time in the next step. Each one and a half step will take the same amount of time as each double step. The quality will not change. Only time will change. Moreover, there is a possibility of excess metal removal. If you take a step too large, for example, after 220 go to 800, the furrows from a rough bar will have to be leveled so thin for a very long time. As a result, to achieve the same quality, with a large difference in graininess in each step, the time costs will have to be increased.
If you want to do the job quickly without sacrificing quality, choose the right tool, and in terms of grit, choose the right abrasive pitch.
In other words, it's okay if, in the absence of an intermediate abrasive, you went from 180 Japanese grit to 800. It will just take a little longer to work, and the wear of the 800 stone will be a little more. But, on the contrary, by adding a lot of intermediate ones, for example 240, 320, 400, 600, you will not only increase the time costs, but also, most likely, remove too much metal. AT this example it is better to insert 1 stone at 320 or 400 grit, although you can insert nothing, just slightly increasing the processing time.
In conclusion, about abrasives, I want to note that if you do not make knives yourself, but only sharpen existing ones, you need an abrasive coarser than 400 Japanese grit (European standard F280, grain 36 microns.), just in case. But for jobs that require an abrasive coarser than 400 grit, it is better to use not a bar, but an electric grinder. Thus, the bars usually sold for sharpening knives are just not suitable for it. They can only perform preparatory work before sharpening knives. And they are sold everywhere just because they are cheap. An ordinary buyer cannot be convinced that you need to buy a stone 5 or even 10 times more expensive. He would prefer to take a bar for a dollar and not delve into the intricacies of sharpening skills. Accordingly, there is no one to sell normal grindstones for, and therefore there is no need to put them on sale. In addition, for most sellers, whetstones are just a related product, in which they understand no better than ordinary buyers.
Stone(bar) - an abrasive connected by some cementing ligament. At home, you can get it by mixing cement with quartz sand. However, industrial stones are made from more sophisticated bonds and abrasives. For whetstone great importance has the link on which it is executed. For example, diamond bars are often made by electroplating a diamond on a metal plate. Such bars rip off metal very aggressively, as they have very sharp and very hard diamonds sticking out strongly. They are well suited for forming slopes on the plate in the process of turning it into a knife and for restoring a badly killed knife. They are also the only method of sharpening ceramic knives. However, under excessive pressure, diamonds can tear out of the bond, which leads to baldness of the bar and loss of its sharpening ability. In addition, diamonds cut deep grooves in the metal, which, if not aligned, will quickly dull.
Some abrasives are not very strong and quickly become blunt, rubbing against the metal that is sharpened on them. To prevent the stones from losing their abrasive ability, brittle abrasives are often kneaded in a soft bond, which gradually grinds away, allowing the worn abrasive to crumble and expose fresh, not yet worn abrasive. This is how, for example, Japanese synthetic water stones Naniwa Professional (formerly called Chaucer) are made. However, the disadvantage of these stones is their rapid development, leading to a thinning of the stone and the formation of pits on them, which do not allow normal sharpening. As a result, soft-bonded stones, although they retain their abrasive ability, need systematic leveling (on glass, another stone, or even on a road curb). It is good to sharpen very hard steels with such stones, since they will never become dull. Also, they will not lead to chipping of the edge, since under excessive pressure the bond of the bar is broken, and not the steel being sharpened.
Stronger abrasives are often fixed with a rigid bond. The most rigid is ceramic. There are 2 types of ceramic bond: ceramics and glass-ceramics (vacuum-dense ceramics). In ceramics, the bars are brought to a temperature where the clay begins to sinter. And they are called bars on a ceramic bond. Glass-ceramic is produced at much higher temperatures, at which the clay turns into glass, in a vacuum environment to remove bubbles. They are usually referred to not as vitrified bars, but as ceramic bars or superhard ceramics. Ceramic bars practically do not wear out, but their price is not small, and their range is not large, since not every abrasive can withstand the glass transition temperature of ceramics. At the moment, corundum (aluminum oxide) is used in ceramic bars, as it withstands required temperatures. Therefore, bars are often called alumino-ceramics. Ruby (a kind of corundum), zircon, cubic zirconia, chromium sesquioxide, boron carbide, silicon carbide can also theoretically be used in glass-ceramic bars. The disadvantage of glass ceramics is its high hardness. From excessive pressure on glass-ceramic on the edge of a knife made of brittle steel, chips may appear. If you press too lightly, the speed drops.
Some bars are made using an organic binder (Venevsky Diamond Plant, Naniwa Super Stone and others).
How roughly or finely the grindstone will work is determined by the height that the top of the abrasive rises above the rest of the surface of the bar and the distance between the tops of adjacent abrasives. In synthetic (artificial) stones, this is almost always determined by the size of the abrasive grain filling it. However, in a number of cases, the grains coalesce and intertwine with each other (typical of quartzite), or fuse into each other (glass-ceramic), so that the distances and heights depend on the degree of intergrowth (fusion). In this case, they say that the stone sharpens not with grain, but with structure.
Suspension- gruel of abrasive and water (oil). Either induced from a powder (or nagura), or formed as a result of grinding a stone. The presence of slurry on the stone will usually speed up sharpening, but can make it rough when working on very thin stones. And the thickening of the suspension on thin stones leads to a relative blunting of the edge (relative to what could be obtained on a clean stone).
Nagura- volcanic tuff (natural nagura), containing abrasive grains and a very soft binder, comparable to the strength of chalk, as a result of which it is used as a suspension stone. Thanks to the nagura suspension, it is possible to increase the roughness and aggressiveness of a thin stone, or to increase the productivity of a stone with the same grain size as the nagura. Due to the very high price of nagura and the fact that it only slightly speeds up the process, only special connoisseurs use it outside of Japan.
Naguru can also be used to clean the bar from clogging or as an independent bar. But in the case of using nagura as an independent bar, its wear is very high. It's cheaper to buy new knives than to sharpen on a nagura.
Sludge- worn metal.
coolant(coolant) - There are 2 main types of coolant used in sharpening: oil and water. They are called lubricating-cooling, because in sharpening, drilling, cutting materials with machines such as an electric grinder, drill, grinder, mechsaw and others, local overheating occurs, leading not only to loss of material properties (hardened steel loses hardening), but also destruction of the material and tool (locally overheated glass bursts, diamond abrasives ignite when heated above 800 degrees). There is a need to cool the area of contact between the tool and the surface being machined. Also, to reduce wear, there is a need to lubricate.
When sharpening without the use of machine tools, the cooling capacity of the coolant does not matter, since critical overheating without high speeds is unlikely. However, lubricity is still important.
Actually, the process of sharpening a knife
If you are making a new knife from a plate, grind it sequentially on 120 and 240 grit stones, creating descents on it and removing so much metal that in the end on each bar the end becomes twice as thin (of course, it’s easier to start on an electric grinder). After 240 stone, the end should have a thickness of the order of a millimeter. Then grind the resulting workpiece with sandpaper or thinner bars, thus obtaining a very dull knife.
On a very blunt knife or a knife with a damaged edge that needs to be corrected (if the edge is bent, it is advisable to straighten it with the butt of another knife or musat before sharpening so that it does not scratch the grindstone and does not break out), it is necessary to form a cutting edge with a stone of 240-400 grit, making a lead. In this case, a burr should appear on the edge. This burr will indicate that the edge is completely machined, and you can proceed to the next step.
Before moving on to a thinner stone, you need to remove the burr by moving the knife butt forward, as if you were cutting the razor on the skin, on a piece of wood or, in extreme cases, on the same stone without pressure (another way to remove the burr is to change the sides of the knife with each pass).
Starting at 400 grit, the burr must always be removed when moving to the next stone or when sharpening is completed.
By sharpening a knife on a 400 grit stone, you get a knife of medium dullness, which, nevertheless, can begin to shave uncertainly. You can stop at this, but the edge will not be stable and will quickly become dull. And the sharpness is not enough for delicate work. Therefore, I recommend switching to an 800 grit bar.
800 grit is a stone for sharpening a not very sharp knife. After receiving and deburring this stone, the result is a knife that shaves uncertainly and has a relatively resistant edge. For many kitchen knives, this is enough, since once they are cut on a plate, it will be dulled regardless of the edge hardness (the hardness of the plates is much higher than the hardness of steel). However, if the knife is used only for cutting on wooden boards, or it is a chisel that requires the highest sharpness and durability, you need to sharpen on a 1500 grit stone.
1500 grit is the limit for a classic European kitchen knife (but not for a chisel and planer blade). After removing the burr, the knife will shave well without scratching, chop tomatoes without crushing, and it will be good to keep sharp.
But if this is not enough, sharpen on a bar of 3000 grit and above. As a result, you can bring on the skin with GOI paste. But the skin should not hang freely. Due to its softness, it flexes under the edge. A hole is formed in the skin, giving the edge of the knife a large radius and, thereby, blunting it. Ideally, the leather should be hard and glued to the wood base to form a leather whetstone.
In other matters, after stones of 10,000 grit and above, a leather bar is not needed. But these stones must be perfectly polished. Due to the complexity of this task and the high cost of fine-grained stones, leather is preferred by many.
To sharpen quickly, you need to take the right bar. For example, a 60-grit diamond will give the plate the shape of a knife in a minute, while a fine-grained corundum block will not be able to do it in an hour. Therefore, it is very important to choose the right grit and aggressiveness for a particular task. You can accelerate the rough peeling of hard steels with a diamond. For mild steels by priority: corundum, boron carbide, silicon carbide. It is good to use a sharpening system. It will not only make the work more accurate, but also by eliminating the processing of unnecessary, will reduce time costs.
I do not recommend trying to get an invisible edge with a large abrasive. Especially the diamond. Coarse abrasive creates deep furrows. If these grooves remain after sharpening, the knife will cut perfectly, but also quickly become dull as the teeth formed by the grooves break out. Moreover, deep grooves can lead to cracks and chips.
In order not to remove excess metal from the knife, with abrasives from 200 grit and coarser, it is better not to make descents thinner than 1 millimeter at the end and not to grind the cutting edge if it does not require alteration.
With a 400 Japanese grit bar, you can bring the slopes to 0.8-0.4 millimeters and shape the cutting edge so that its end is not visible to the naked eye.
The edge is never perfect, consisting of a line one atom thick. There are thousands or even millions of atoms on the edge. They form a rounded edge. The smaller the radius of this rounding, the sharper the knife. But the abrasive always pulls out metal particles when moving away from the edge and drives them inward when moving to the edge. The size of these particles is comparable to the grain size. As a result, if you go to the edge with a rough stone, it will leave teeth with relatively sharp tops and blunt bases. To increase the sharpness, you will first have to grind these teeth to the base, thereby reducing the knife in size. The thinner the abrasive, the thinner both the tops of the teeth and their bases will be. The smaller the edge radius and the sharper the knife. Therefore, in order not to reduce the size of the knife, you do not need to go to the edge with a rough stone. You need to go to the edge with bars that give an acceptable sharpness, those on which, in principle, you can finish sharpening (for example, a knife cuts quite well at 400 grit).
The knife will be easy to cut even at large sharpening angles, if finished on a very small stone. Due to the large angle, it will slightly jam (blunt) when colliding with solid particles, and due to the finish on a thin stone and the small size of the teeth, the teeth will break out less when cutting (dulling the knife). Thus, by setting the knife at a relatively obtuse angle, but fiddling with it on thin stones, you can get a knife that will cut frozen meat and fish bones without hemming and without losing sharpness, but at the same time, cut tomatoes well. For these operations, of course, it is better to have different knives. However, thin stones, by increasing the time spent on sharpening, not only increase the durability of the knife, compensating for the time spent, but also increase its versatility. Knives with an obtuse angle begin to cope with delicate tasks, and knives with a sharp angle are less afraid of rough work.
When trying to increase edge durability, it is important not to overdo it. Our kitchens are dominated by mild stainless steel knives. For example, the widely used Tramontina knives with a wooden handle have a hardness of 52 HRC. When sharpening such a knife to 10 thousand grit, the edge becomes much thinner than a hair, thinner than any foil. With such a thickness and such soft steel, it bends and smoothes, almost from a breath of wind. If you cut with pressure, the knife will cut and shave well (until the edge is bent). But if you cut by pulling, because of the smoothness, it will slip (soap). And it turns out that the same knife, sharpened to 1500 grit, cut better by pulling due to the relatively large saw on the edge, which is more resistant to burnishing. And it takes a lot of time to grind up to 10,000 grits. And it is more difficult to control such a fine sharpening, because due to the microscopic dimensions, it is no longer clear to the eye or to the touch whether the edge is well machined with another abrasive. But it turns out that the time wasted in vain, and at the initial stage the knife cut better. Plus, you need to take into account the thread on the plates, which kills sharpening in one movement. So, in each specific case, you need to determine your reasonable limit, and not mindlessly sharpen up to 20 thousand grits with a $250 Suehiro Gokumyo GMN200 stone just because someone wrote so on some forum.
It is important that when sharpening on thin stones, in order to avoid metal wrapping on the edge and the formation of craters, the knife must be moved with the tip in the direction of travel, or at least with the tip in the direction of travel as well (that is, as a last resort, unless otherwise inconvenient to sharpen back and forth). On rough stones, it is also better to move the tip forward in order to quickly expose the middle (edge). However, after finishing sharpening on rough stones, it may be useful to make a few movements with the point from the direction of travel to break off microburrs.
Time costs
With the right selection of bars, sharpening even a heavily killed knife to razor sharpness, even without a sharpening system, will take only a few minutes.
Do not listen to people sharpening a powdered steel knife with a hardness almost like diamond on a Japanese water stone or Arkansas. Diamonds sharpen diamonds!
Do you want to spend a week sharpening?
Do you want to level the bars on glass with silicon carbide powder for several hours after that?
Do you want to spend several salaries on unproductive bars?
If yes, full speed ahead, natural stones, Japanese watermen... and be patient.
Other gurus offer to sharpen everything with Venevian diamonds on an organic bond. They can be understood: why, in our technological age, hold on to the technologies of the Stone Age? Down with natural stones, down with too troublesome Japanese water workers! A few minutes and the knife is sharper than a razor!
But expensive. And, in fact, the cutting ability and resistance to blunting of the knife will not be perfect.
For those who are not ready to spend half their salary on grindstones, there are at least technological solution: diamonds on a galvanic bond for rough sharpening, aluminum oxide, boron carbide and silicon carbide in the middle of the path (but finer-grained diamonds are also possible), allumoceramic or natural stones at the final stage.
That is, a combination of different types that are most suitable for specific operations.
The speed is about the same. The cost is much less. Instead of carbides, stones from various types of corundum can be used. A little slower work, a little more often to update stones, but very cheap! The main thing is the correct grain size, the correct step, and not to remove excess metal, not to try to get a finished edge on a bar that is too rough. As the end of the edge thins, move on to a thinner stone. You don’t have to remove the excess, you don’t have to spend extra time and grind the knife.
Division of whetstones by coolant type
Since there are 2 main types of coolant (oil and water), in addition to the type of bond, type of abrasive and origin (natural or synthetic), it is customary to divide whetstones into oil and water. Water bars do not need to be moistened with distilled water. Just as oil is filled with different additives for different purposes, so water can contain "additives". For sharpening, any not too dirty water from a tap or reservoir will do. To reduce its volatility from the surface of the bar (with manual sharpening) and increase the ability to keep the sludge afloat, glycerin can be added to it. To reduce the absorption of sludge, detergent can be added to the bar. These additives will not change the essence of the coolant: water with "additives" will remain water.
The same can be said about oil: diluted oil or oil with impurities does not change its essence. Moreover, the word "oil" in this case should be understood wider than the usual ideas about it. Firstly, oil consists of fatty acid esters and, for example, oleic acid, as if not an oil, is an excellent coolant, and secondly, instead of oil, you can use any oily or soapy liquid, be it kerosene, glycerin or, even detergent (for lack of a better one).
Of course, whetstones do not have to be used with exactly the type of coolant recommended by the manufacturer. But this will not do without negative consequences: Arkansas on the water will clog with sludge and stop sharpening, the Soviet silicon carbide bar will be dirty with oil absorbed into it until the end of days. Therefore, it is better to use the bars as the doctor prescribed. And if this is done, features are revealed in the bars: water bars emit a suspension consisting of a freely rolling abrasive. This causes them to wear more (than when used with oil), but sharpen faster. On fine-grained stones, another feature appears: fine-grained oil stones give precise strokes, smoothing the metal around them and, thereby, creating a mirror effect. Unlike them, in waterstones, the formation of clear strokes and smoothing is prevented by a cushion of suspension, which, breaking the contact of the bar with the surface to be treated, leaves its own short strokes and a matte effect.
Eventually stones in water generally work faster, while stones in oil result in a faster surface with a high degree of reflection and a more aggressive cutting edge.(due to sharper strokes on it, which is good for knives, but bad for razors). This ability is used by craftsmen: having worked with a knife on a water block with water, they finish it dry to obtain an average result between oil and water stones.
There are bars that are positioned as bars for dry operation. These include vacuum-tight ceramics and diamonds on an organic or galvanic bond, as well as Naniwa Super Stone. However, oil-only vacuum-tight ceramics can be kept from clogging with sludge, and electroplated diamond plates lose speed if the sludge is not washed out with water. As a result, diamonds and Naniwa Super Stone work better with water than dry, and should be classified as water bars, while vacuum-tight ceramics work better with oil, and should be classified as oil.
For conventional knives and knives made of steel subject to rust, it is better to use oil stones. For knives with Scandinavian slopes, when sharpening without a micro-supply, it is better to use water stones, since wide slopes float on oil, almost without touching the edge. If you have to use an oil stone on scandispos, instead of oil, it is better to use either a detergent solution, or a very thin oil or kerasin. In general, aquatic kaini are more versatile. However, some steels can rust when sharpened for a long time.
Do not sharpen soft steels with diamond stones on a galvanic bond. The diamonds will cut deeply into the steel and gradually break out of the bar. Diamond whetstones are designed for sharpening very hard steels that slide over ordinary bars without sharpening.
Do not sharpen very hard steels, such as chisels and quick cutters, with bars on hard bonds, such as vacuum-tight ceramics. The abrasive will gradually blunt, but the bar will not renew itself, so the bar will quickly lose its abrasive ability. Alumina-ceramic bars can serve without wearing out for a long time, provided that very hard steels are not sharpened on them, so as not to render them unusable. Vacuum-tight ceramic whetstones are very good for sharpening relatively soft stainless steels, with hardness up to 58 (you can sharpen and steel is a little harder, but the harder the steel, the more the bar will be smoothed out).
Japanese synthetic water stones and their soft bond counterparts are suitable for most steels. However, many of them wear out relatively quickly (although there are also bars on a relatively hard bond). This erasure causes a renewal of the abrasive. Instead of a dull one, a new, sharp abrasive appears on the surface. This is the reason for the versatility of these bars: they sharpen any steel, as they are constantly updated. Due to the rapid renewal, the stones do not get clogged. But grinding, they lose their shape, require alignment and are gradually consumed. Buying new stones to replace worn ones is somewhat expensive, and leveling those that have lost their shape is troublesome. But, worst of all, many of the branded Japanese stones are demanding on drying conditions and can crack when fast drying. Keeping them wet, as is customary to do with Russian stones, is also impossible for many, since the most expensive Japanese synthetic stones are made on a gradually sagging magnesian bond. That is, when buying a Japanese synthetic stone, you need to understand very well how to work with this particular stone, the methods of exploitation of which can be very different from the methods of exploitation of other stones (including stones of the same company, but of a different series). Particular care must be taken with the bars glued to the stand. Due to the difference in the degree of deformation during swelling and the difference in the rate of swelling-drying, the bars glued to the supports tend to burst.
There can be no consensus on Japanese water stones similar to Naniwa Professional (formerly Chaucer). On the one hand, they are universal and sharpen everything. On the other hand, they need to be wetted, but then dried very carefully so that they do not become limp and cracked. They are clearly not as good as they are expensive. Needless to say, if sandpaper pasted on a piece of moisture-resistant chipboard costs 4,500 yen! For rough work, they are often inferior in performance to wear-free and cheaper Venevian diamonds (and even more so, galvanized diamonds), and for fine work they are inferior in quality to good specimens of natural stones.
But buying a Japanese is easier than a good one. a natural stone. Natural deposits are depleted, and Japanese synthetics are inexhaustible.
Natural stones have different properties and there is no general recommendation for them. They are of 2 types: some, in fact, are petrified silt with an admixture of silicon dioxide. Where silicon dioxide is an abrasive and silt is a binder. These natural stones do not have fundamental differences from synthetic ones. Contrary to popular belief about the inapplicability of the concept of grit to natural stones, silicon dioxide works according to its grit, no matter how the stone was originally polished. Just keep in mind that the strength of silicon dioxide is much lower than that of synthetic abrasives, and it quickly grinds, giving a softer sanding. These stones work by releasing a suspension. Other stones, in particular, quartzites (black hard Arkansas and Arkansas translucent), are practically pure silicon dioxide, the crystals of which have grown together. Their granularity is determined not so much by the size of the crystals as by the degree of polishing of the stone.
Quartzites have unique properties. They are mounted not with glue, but with time. It will take millions of years to reproduce artificially.
As a result, each natural bar should have its own recommendations. But personally, I don't see the point in using natural stones below 1500 grit. Diamond, silicon carbide, aluminum oxide (corundum), and often boron carbide, work faster and are better for fast metal removal.
Venev diamond bars on an organic bond have proven to be wear-resistant and sharpening any steel. But I would not recommend sharpening soft steels with them, so as not to increase their wear (because diamonds there are no less sharp than diamonds on a galvanic bond, and also, bogged down in soft metal, can be torn out of the bond). In addition, manufacturers made a reservation that on fine abrasives, somewhere from 1 micron (about 10 thousand grits), the powder can clump uncontrollably, forming clots in the bar, leaving rough scratches on the treated surface. Thus, the question arises, will a 10,000th organic-bonded diamond bar give sufficient polishing cleanliness? And in general, is this disease not characteristic of other artificial bars? Will 10,000 grit synthetic stones give the clarity of a good natural stone? Judging by the fact that large inclusions are sometimes found even in expensive Japanese synthetic stones, manufacturers of artificial bars cannot completely get rid of this problem.
Summarizing the information on the bars, you can offer options:
- Proper selection of natural stones;
- a set of Japanese water stones;
- Venev diamonds on an organic bond;
- a combination of galvanized diamonds for hard steels and ceramics for the rest.
The options are listed in order of cost and the hassle of caring for the bars (the need to level and grind). Although, often, caring for water stones is more troublesome than natural ones. At the same time, Japanese water companies can be replaced with cheaper analogues and make the option the cheapest, but still very troublesome.
The speed of work on each of these options depends on the metal being processed, but in general, option 3 is the fastest, and option 4 is only slightly inferior to it in speed. However, after diamonds, even Veneva ones, it is better to finish with a less cruel abrasive. For example, having sharpened a knife with a hardness above 61 with a galvanized stone to 800-1500 grit, bring it to good resistance on 1500-3000 grit bars of aluminum oxide (corundum) on a relatively soft bond. And then, for maximum durability, bring on a good natural stone 5000 grit and above. Thus, both the maximum speed and maximum quality, and a very low price (price compared to sets either from pure Venevian organic bars, or from Japanese high-quality synthetics, or from natural stones). An attempt to reduce the cost of a set of stones even more will lead either to a loss of speed (sharpening only on cheap aluminum oxide bars), or to a loss of quality (sharpening only on electroplated diamonds), or to the loss of both at the same time.
On the other hand, for kitchen knives, speed is usually not important. And the quality does not matter if the knife is immediately thrown into the sink, where it will get dented by hitting other knives, forks and plates. And then cheap aluminum oxide bars are quite appropriate. And 1500 grit is overkill. Sharpening such knives with a stone thinner than 800 grit is a waste of time. Edge stability will still be compromised by careless handling. Only if the attitude to the knife is careful, does it make sense to fine-tune it.
You should not buy thin Venevian diamond bars with a low percentage of filling. Having made a budget option, the managers of the Venev plant promote it, arguing that neither in terms of speed of work, nor in quality, fine-grained bars with a low diamond content are inferior to bars with 100% filling. However, due to high density diamonds, each individual diamond experiences more pressure when working and cuts harder into the metal than at 100% filling, making the processing rougher. Thus, bars with 100% filling work more accurately. And if they seem too expensive, then it is better to think about electroplated diamonds or other abrasives.
To get a visual representation of the difference in filling, pinch 4 studs between your fingers to form a mini-comb and scratch your hand with it. It might even be enjoyable. Then try scratching with one nail. It probably won't be pleasant. This is the difference between 100% and 25% Venevian bars. 25% with bars you hurt the metal! Of course, diamonds do not stick out of the bar like nails, and the effect is not so terrible, but, nevertheless, a 100% bar sharpens faster and better.
Starting from 8 thousand grits, the bars do not sharpen as much as smooth the metal (but for this they must be well polished, otherwise they will work much rougher than their grit suggests). So, if you don't need a mirror surface, then you don't need high grit bars. They won't sharpen. Their task is to even out the smallest irregularities that accelerate the blunting of the knife.
In addition to choosing the type of bar, it is of great importance proper grit selection. If the knife has stopped chopping tomatoes, but cuts them well, you need to start sharpening it with about 1500 grit. If the knife does not cut tomatoes well - 800 grit. If the knife cuts very badly - 400 grit and coarser. No need to start sharpening a slightly dull knife with a rough bar. So you will not achieve more sharpness or speed, but more wear on the knife. It is better to sharpen the steel a little longer with a thin bar than to sharpen the steel unnecessarily with a rough one. In addition, smoothing the furrows from a rough stone may take longer than sharpening directly on a fine one.
The hardness of the bond and the density of the content of abrasive particles is also of great importance. A solid bar does not lose particles and if the particles are cut off the tops, the abrasiveness is reduced. At rough stages, this negatively affects speed. But in the middle stages, especially at high particle density, it can be used to make a bar with a relatively coarse grain give a smoother surface. This is sometimes used to make Translucent or cermet give a fine razor finish. The same is often used by rubbing different sides of the stone on powders of different grain sizes in order to sharpen quickly on one side and finely finish on the other. But this feature should be taken into account simply when selecting stones. For example, after a hard stone at 800 grit, the knife will be sharper than after a soft one at 1500, although the strokes after 1500 will be finer, and the surface finish and durability will be higher. In this regard, it is often said that one cannot compare the grit value of natural stone (usually having a high hardness and a quickly grindable, polishable abrasive) or glass-ceramic, with the grit value of synthetic stone. But this is a simplified approach that interferes with understanding the physics of the process. By and large, different stones cannot be compared in terms of grit value at all. A soft alumina stone will work in a completely different way than a hard diamond with the same grit. The hard silicon carbide stone will also give its character to the work. And on a soft silicon carbide stone, you get the 4th option. And all with the same grain size. Grit is only one of the guidelines for abrasive ability. Bond hardness is another benchmark. Soft stones with the same type of abrasive work faster, while hard stones give greater sharpness. Accordingly, for the initial stages, if the wear rate is not critical, soft stones are preferred. And for the finish, hard ones are better. For example, sharpening a razor to 3000 grit is good on soft ones, and then move on to hard ones. And a kitchen knife that you are not going to spend a lot of time on can be finished on a hard stone of 1000 grit. However, it can be sharper than 3000 grit on an expensive but softer Japanese water stone. That is, by choosing the right hardness, you can get an inexpensive sharpening set that gives the same sharpness as a large and expensive set of stones with an unsuccessfully selected hardness (but keep in mind that the hardness of the bond provokes clogging).
The density of the particles is almost always the better, the more. Only if you need to loosen the surface, low density becomes useful.
| Material | Density, kg/m3 | Mooca hardness | Microhardness, GPa | Modulus of elasticity, GPa | Relative abrasive ability | Ultimate compressive strength, GPa | Temperature resistance, °C |
|---|---|---|---|---|---|---|---|
| Diamond natural C | 3520 | 10 | 98,4 | 900,0 | 1,0 | 2,0 | 700–800 |
| Diamond synthetic C | 3500 | 10 | 84,4–98,1 | 720,0–930,0 | 0,8 | 2,0 | 700–800 |
| Elbor BN | 2340 | 9 | 92,5 | 720 | 0,58–0,60 | 4-5 | 1100–1300 |
| Corundum (aluminum oxide) Al 2 O 3 | 4020 | 9 | 20,0 | 357 | 0,10–0,14 | 1,1–1,6 | 1700–1800 |
| Electrocorundum (aluminum oxide) Al 2 O 3 | 3900 | 9 | 19,2 | 350 | 0,14–0,16 | 0,7-0,8 | 1250–1300 |
| Carborundum (black and green silicon carbide) SiC | 3200 | 9 | 34,0 | 365 | 0,25–0,45 | 1,5 | 1300–1400 |
| Quartz (silicon dioxide) SiO 2 | 2700 | 7 | 12,5 | 70 | 0,05–0,07 | 0,4 | 1500–1800 |
| Boron carbide B 4 C | 2500 | 9 | 41,0 | 296 | 0,40–0,50 | 1,8 | 700–800 |
Quartz widely distributed in nature in the form of sand, sandstones, quartzites, etc. Possessing a relatively low abrasive ability and strength, it is practically not used in synthetic whetstones. Quartz is the abrasive used for grinding slates, which is petrified clay mixed with quartz dust (silicon dioxide). It does a good job with classic steels. But not effective for powder.
Corundum(Electrocorundum) due to the relatively low abrasiveness due to the rounded shape of the grain (partially compensated by alloying and, for example, chromium electrocorundum - technical ruby - has sharper edges), does not very effectively remove hard metal when normal pressures. But, having high strength (for example, in relation to brittle silicon carbide), it retains its abrasive ability for a long time. When used on fine-grained, hard-bonded bars, they produce inexpensive wear-resistant bars. And when used on coarse-grained bars, it allows you to increase the speed of processing mild steels by increasing the pressure (for rough processing, an increase in pressure is acceptable, but silicon carbide would crumble, preventing an increase in speed). In general, corundum stones are the most unpretentious and are usually used for sharpening stainless steel knives.
Carborundum(in translation it can be referred to as "green carbon stone" or silicone carbide), having medium abrasiveness and low price, it is used in sandpaper and grinding powders, allowing you to quite effectively remove metal of various hardness and viscosity. However, it is afraid of pressure and collapses into small particles, losing the ability to quickly remove. Therefore, in rough operations, it is often replaced by cheaper corundum, which makes it possible to increase the processing speed by increasing the pressure. Due to the low deformation strength, it wears out quickly when machining tough steels. And, despite the general versatility of silicon carbide, it is more practical to use electrocorundum bars for sharpening stainless knives. However, the rapid wear of silicon carbide (as well as silicon dioxide) gives positive effect on fine-grained bars: grinding on the suspension obtained from the destruction of crystals gives a cleaner surface. Therefore, fine finishing and grinding, ceteris paribus, is best done not on aluminum oxide, but on silicon carbide or silicon dioxide - quartz.
Boron carbide according to the table has a fairly high abrasiveness. However, it should be borne in mind that this is an indicator of the amount of glass abraded when 1 gram of free-rolling abrasive is worn (in relation to the amount of glass erased by the same mass of diamonds). Since boron carbide is light, there will be one and a half times more abrasive particles in 1 gram than electrocorundum. Therefore, when comparing the speed of 2 bars of the same size, one of which is boron carbide and the other aluminum oxide, the relative abrasion of the boron carbide bar, theoretically, should be one and a half times less than expected from the table. In addition, the ability to abrade a large amount of glass for boron carbide is determined not so much by its cutting ability as by its wear resistance, which is more than 2 times higher than the wear resistance of electrocorundum. Boron carbide does not wear out longer, due to which it surpasses electrocorundum in "relative abrasive ability". In fact, if we compare the wear time of abrasives and the result obtained, the speed of boron carbide will be lower than that of electrocorundum. This happens because when crushed, boron carbide does not give sharp edges. But it has high strength, keeping the specified abrasiveness for a long time. As a result, it is usually used not in bars, where it would surpass cheaper aluminum oxide only in wear resistance, but in the form of powders and pastes for finishing cutting tools made of superhard materials like tungsten carbide and titanium carbide alloys (where corundum and carborundum would quickly wear out). However, boron carbide can be used in bars for mild steels, which can be processed without dulling. Due to the high wear resistance of boron carbide, such bars are logical on a very hard bond. As a result of the hardness and grain and bond, very wear-resistant whetstones are obtained. But this creates the problem of clogging, since the layer clogged with sludge does not crumble itself. Accordingly, when using a boron carbide bar with a hard bond, care should be taken to prevent clogging, and if it occurs, refresh the bar by cleaning or peeling off the clogged layer. It is these difficulties and the limitation to mild steels that have led to the unpopularity of boron carbide bar. However, when other types of bars are available, hard bonded boron carbide bars can be used on milder steels to reduce overall bar wear and thus reduce the cost of sharpening in the long run. Moreover, due to the combination of high hardness and roundness, boron carbide removes metal ruffled by coarse abrasive, leaving a smooth surface. This allows you to start grinding immediately after roughing, reducing the time spent on sharpening and reducing the need for medium-grained stones.
Experience shows that boron carbide is effective on steels up to 55 HRC. That is, it works well on almost all cheap stainless knives, including the cheap Tramontina series. But on Tramontina Professional Master and more expensive Tramontina knives, its effectiveness drops noticeably. That is, depending on your knives, it can be either an eternal, indestructible bar, or a useless bar.
Diamond(mostly synthetic), having high hardness and strength, cuts metal like plasticine. Due to the high cost, to obtain a bar, it is usually applied to the plates with the thinnest layer. But from this layer, grains of diamonds are pulled out by viscous steels. Therefore, it is most advisable to use for processing very hard steels and ceramics, which are difficult to process with other abrasives.
Elbor(cubic boron nitride) is almost as hard as diamond. In addition, it has good chemical resistance and withstands higher temperatures than diamond, which allows it to be used for fast cutting and grinding, significantly increasing the processing speed on machine tools. At manual processing, where there is no high temperatures, no contact with aggressive environments, has no special advantages over diamonds, and therefore, due to the cost exceeding the cost of synthetic diamonds and low abrasive ability, the use in whetstones is not economically justified.
| GOST 52587-2006, ISO 525:1999 | Previous guests (18118, 19202, 21323) | Decryption |
|---|---|---|
| F | VM1 | Very soft. High renewability, which does not allow the bar to be smoothed out. Appointment: Grinding of big planes, flat grinding. |
| G | VM2 | |
| H | M1 | Soft |
| I | M2 | |
| J | M3 | |
| K | CM1 | Medium soft |
| L | CM2 | |
| M | C1 | Average |
| N | C2 | |
| O | ST1 | Medium hard |
| P | ST2 | |
| Q | ST3 | |
| R | T1 | Solid |
| S | T2 | |
| T, U | WT | Quite hard |
| V, Q, X, Y, Z | Thu | Extremely hard. Maximum shape retention. Purpose: Sharpening tools with a small contact area (awl, narrow chisels, etc.) |
Marking of Russian-made whetstones
A - electrocorundum
C - silicon carbide
V - ceramic bond
B - bakelite bond
| Average size, µm. | GOST | Europe, Russia | ANSI | JIS | Operations in progress | |
|---|---|---|---|---|---|---|
| FEPA-F | FEPA-P | |||||
| 320 | 25 | P60 | Removal of rust and dirt, cleaning of welds. Not used for metal removal, as it will require an increase in pressure, which will lead to excessive wear of the abrasive and deformation of the processed material | |||
| 270 | F60 | #60 | ||||
| 240 | 20 | F70 | P80 | |||
| 190 | 16 | F80 | P100 | |||
| 160 | F90 | #90 | ||||
| 135 | 12 | F100 | P120 | #100 | Roughing, shaping | |
| 125 | 100 | #120 | ||||
| 115 | 10 | F120 | P150 | |||
| 80 | 8 | F150 | P180 | 150 | #150 | |
| 70 | 6 | F180 | P220 | 180 | #180 | |
| 60 | F220 | 220 | #240 | Rough tool sharpening | ||
| 58,5 | P240 | |||||
| 53 | 5, M63 | F230 | 240 | |||
| 52,2 | P280 | #280 | ||||
| 46,2 | P320 | #320 | ||||
| 44,5 | 4, M50 | F240 | 280 | Basic tool sharpening | ||
| 40,5 | P360 | 320 | #360 | |||
| 36,5 | F280 | |||||
| 35 | M40 | P400 | #400 | |||
| 30,2 | P500 | Grinding. The surface of the metal becomes matte, the strokes are barely visible to the eye. | ||||
| 29,2 | F320 | 360 | #500 | |||
| 25,8 | M28 | P600 | 400 | #600 | ||
| 22,8 | F360 | |||||
| 21,8 | P800 | 500 | #700 | |||
| 18,3 | M20 | P1000 | 600 | #800 | ||
| 17,3 | F400 | |||||
| 15,3 | P1200 | #1000 | ||||
| 12,8 | M14 | F500 | P1500 | 800 | #1200 | Fine grinding, glass grinding. The strokes on the metal become indistinguishable to the eye and the metal acquires a uniform sheen. |
| 9,3 | M10 | F600 | P2000 | 1000 | #1500 | |
| 6,5 | M7 | F800 | P2500 | 1200 | #2000 | |
| 4,5 | M5 | F1000 | 1500 | #3000 | ||
| 3 | M3 | F1200 | 2000 | #4000 | Final polishing, finishing of razors and chisels. The surface of the metal becomes a mirror. | |
| 2,5 | #5000 | |||||
| 2 | M2 | F1500 | #6000 | |||
| 1,2 | F2000 | #8000 | ||||
| 1 | M1 | #10000 | ||||
| Average size, µm. | GOST | FEPA-F | FEPA-P | ANSI | JIS | Operations in progress |
| Europe, Russia | ||||||
I want to note that the manufacturers of Venevian diamond bars claim that a grain of 1 micrometer corresponds to 12-15 thousand Japanese grits. But it's not. 12-15 thousand grit is already a fraction of a micrometer. However, regarding the bars, the statement of the Venevian manufacturers can be true, since in the 1/0 bar the particle size is less than 1 micron, which means that the bar can really have 12-15 thousand grit.
I also want to note that the type of operations performed is indicated conditionally, since everyone determines for himself which grinding is fine for him and which is rough. In addition, by varying the type of abrasive, type of lubricant and pressure, it is possible to increase metal removal for fine-grained bars or achieve finer work from coarse-grained ones. So, the operations performed are indicated only for an approximate idea of the purpose of the abrasive of a given grain size.
In all descriptions I use the Japanese system, since almost no one indicates the grain size in microns, and the Japanese system of grit is commensurate with the grains. That is, in a Japanese stone of 800 grit, the grain is 2 times finer than in a stone of 400 grit. And in the Russian F400 (corresponds to the Japanese 800 grit), the grain is 3 times finer than in the F220 (although the F value would suggest about a twofold difference). Thus, only in the Japanese system does the value correspond to the size (pun intended). For the European system, it would be more convenient to simply indicate the grain size in micrometers. Even more confusion in the European standard is made by sandpaper, which, unlike the bars, is marked as "P" and has its own grain size gradation that does not correspond to the gradation in the bars.
Approximate grits of the most recognized whetstones (Spyderco aluminum ceramics and natural Arkansas):
| grain size, µm. | Japanese grits | Spyderco | Arkansas | Norton India | Norton Cystolon |
|---|---|---|---|---|---|
| 125 | 120 | Coarse | |||
| 80 | 150 | Coarse | |||
| 70 | 180 | Medium | |||
| 60 | 240 | Medium | |||
| 46,2 | 320 | Fine | |||
| 35 | 400 | Fine | |||
| 29,2 | 500 | Washita | |||
| 21,8 | 700 | Soft | |||
| 18,3 | 800 | Medium (grey) | Hard | ||
| 15,3 | 1000 | white hard | |||
| 12,8 | 1200 | fine (white) | |||
| 6,5 | 2000 | Ultrafine | |||
| 3 | 4000 | Black Hard, Translucent |
According to this chart, Spyderco's cermet set is a ready-to-use kit for sharpening not too dull knives to near razor sharpness. Unfortunately, Spyderco does not offer a rough option. Together with him, the kit would allow you to quickly sharpen even very dull knives. But, alas, they do not have the coarse option. But the Arkansas set is presented even redundantly complete for sharpening (some of the stones can be excluded). However, due to the fact that it is a natural stone, it can be inferior to alumino-ceramics in the speed of work. Thus, the price / quality ratio of Arkansas is not justified even in relation to the expensive Spyderco. The exceptions are Translucent stones, which, judging by the reviews, can be polished up to 6000 grit and above, and Black Hard, which, thanks to the close intergrowth of crystals, sharpens to 8-10 thousand grit, and quite quickly. These stones are rightfully considered the best for sharpening knives before switching to leather with paste. Perhaps only Chinese ruby ceramics can compete with Arkansas in this segment, which, judging by the reviews, can be polished to the same degree, obtaining a cheaper analogue. Other fine-grained counterparts cannot compete either in speed or durability.
It is also clear that there is no point in buying Norton India and Norton Cystolon at the moment, since in any city it is easy to find the same rough stones 20 times cheaper. Probably there will be another level of quality. But for such rough work, quality does not matter. With such a striking difference in price, for such rough work, only price and ease of use matter. In the red and purple zones of the table, the quality of the stones can be ignored. The roughing on the Stayer bar is just as good as the roughing on the Norton Cystolon. However, as the grain decreases, the requirements for the quality of the stone begin to grow.
) In particular, GOST determines in which 4 sieves of different sizes how many percent of the grains should settle. As a result, to determine the size, you can take the maximum possible grain size (but there are only a couple of percent of such large grains and they will give only individual scratches), the size of the average of these 4 sieves, or the average size of the main fraction (but not the main one can be contained in enough large number to determine the nature of the processing). In fact, none of the options will give a precise definition. But even if all the grains were exactly the same size, the abrasiveness will depend on the abrasive substance, the type of binder, the cutting fluid (coolant), the hardness and viscosity of the material being processed (which does not directly apply to the abrasives themselves, but is closely related to the substance which the abrasive is made of). Equally important is the pressure. At high pressure, diamond cuts to the fullest possible depth, and silicon carbide simply crumbles. As a result, diamond stones work rougher than carborundum, faster on hard materials, but usually slower on sticky materials. So, even within the same size, the nature of the work of different bars is different. Add here different percentages in different sieves for different standards and we get the possibility of only an approximate comparison of standards.
) Naniwa Professional Stones are not available below 400 grit. Since it is believed that below 400 grit the quality of the stones is not important. And on this page it says that 400 grit is the roughest of the stones needed for sharpening. Rougher stones are needed either to change the sharpening angle, or to fix a chipped knife. That being said, this page states that 1500 grit is the upper limit for many uses and provides a sharper edge than most new knives out of the box.
About the same thing is said on the Suehiro website. Namely, that the main sharpening of kitchen knives is done on stones of 320-800 grit, and final finishing is done at 1000-1500. Sharpening on finer-grained stones, according to Suehiro experts, is not required for kitchen knives.
As you can see, the opinion of Japanese experts does not completely coincide and, in part, is determined by the taste of specific people. But to summarize, their opinion converges on the fact that sharpening kitchen knives requires stones of 400-1500 grit. Rougher stones are needed if the knife has been severely damaged, and thinner stones are needed for specific purposes (for example, for carpentry tools).
