Previously, the process of sharpening knives was considered an important skill of any man. After all, the success in hunting and other difficult matters depended on the quality of this work. Knives were used almost everywhere: from the extraction and processing of food, animal skins to interpersonal wars and upholding the territory.
Due to the fact that the knife is almost the first necessities in the kitchen, it is very quickly blunted and requires sharpening.
Today knives are not used so seriously, but the breadth of their application has not lost its range. They are still necessary tools in the kitchen during processing and cooking, for the repair of various products, as well as for art.
Choosing a knife blade and assessing its quality
With a good sharpening knife will serve you for a very long time, without requiring additional sharpening of the blade. But still the duration of the tool's operation will depend a lot on the quality of the knife itself, and in particular on the material from which the blade is made.
Today the market produces many different knives. And many manufacturers consider their products universal and almost eternal. But advertising always makes its own to increase the demand for goods. Therefore, it is more reasonable to learn at least the minimum criteria for the selection of a knife blade and the timely selection of material for sharpening it specifically.
Depending on the increase in knife size, the material should be thicker and stronger.
- The larger the knife, the thicker the blade should be. In this case, the main thickness does not look sharpened, but at the top blunt side. Here everything must be proportionate. A very large knife should not have too thin a blade even on the cutting part, while a small knife will be thin in itself, and the blade will have a thickness that is barely noticeable to the eye.
- Accordingly, the larger the knife, the stronger it is made of steel. Therefore, it will be necessary to sharpen it more carefully and for a long time. It is recommended to sharpen the largest cutters exclusively on diamond discs or on the most powerful electric sharpeners, since the use of stone is useless in this case.
- When buying a knife, be sure to check its degree of flexibility. A good blade will not bend at all. But if the knife is very thin and still has the ability to bend, then it is important that the blade immediately became its original place. That is, irretrievable deformation is a sign of the very low quality of the material itself.
Sharpening by grinding stone
For high-quality sharpening knives, you can completely do with a special grinding stone.
There are quite a few methods of sharpening knives. The choice of a particular method depends largely on the willingness to spend their money and time, and also on the scope of a particular knife. Therefore, to begin with, we will consider the most inexpensive and widely used method from the old times - sharpening with a special stone. And then briefly focus on sharpening mechanically.
There are two main types of stones for sharpening: artificial and natural. The artificial stone has a larger fraction, it is larger in size. In modern artificial materials of this type, usually one side is less aggressive, and the other has larger grains, which makes the stone suitable for sharpening even large and heavily blunted devices.
Natural stone for sharpening is somewhat cheaper, and it also has a fine-grained structure on both sides. Therefore, it is more appropriate to use it for sharpening knives that are not too blunt and to maintain the sharpness of blades with soft metal from time to time.
Before starting sharpening the knife, the grindstone should be oiled with vegetable oil.
Now proceed to sharpening. But first you need to stone, whatever it was, lubricate with oil. You can use a small amount of regular sunflower oil for this. You need to fully coat the entire bar from all sides, then let the oil soak for about 7-10 minutes. This will make small particles less vulnerable to microscopic microscopic pieces of metal from a knife being driven into them during the sharpening process. Therefore, the stone will serve you much longer.
You can proceed to the main process. The sharpening is done in two stages: first, the rough side, and then the softer one. This refers directly to double-sided artificial stones. The knife must be wiped from dust and applied to the stone like this, while leading the blade with force in the indicated direction.
The aggressive part of the grinding stone will make it possible to quickly remove from the knife the main blunted metal layer. It should be borne in mind that trying to keep the knife preferably at an angle of about 20-25 °. This figure is considered optimal for fast and high-quality sharpening. However, given that the knives today are very different in their forms, one can be too biased not to relate to this recommendation, but to approach the work creatively.
The scheme of sharpening the knife on the grindstone.
While sharpening, you should try to make smooth movements, sufficiently pressing on the blade. Approaching the edge, it is recommended to slightly raise the blade, due to which the sharpening will be better. At the same time, keep the movement perpendicular to the cutting part of the knife.
Sharpening the knife on the aggressive side of the stone must be carefully, periodically checking the opposite side of the blade. A sign to the fact that the basic sharpening is over will be the presence of small nicks on the tip of the blade.Back to table of contents
Important tips when sharpening on an electric sharpener
But today, not everyone wants to sharpen knives with a stone, no matter how good it is. Therefore, use for this purpose an electric sharpener. It is usually used in large enterprises for the manufacture of tools and various household materials from metals, as well as in metallurgical workshops.
Sharpening a knife on an electric sharpener is much easier and faster. It does not make sense to focus too much on the corners while holding the tool, as modern electric sharpeners are able to independently adjust the degree of slope. Knowing that the sharpener process is much faster, consider a few important points:
The scheme of sharpening a knife on an electric sharpener.
- To sharpen a knife, which will serve as a tool exclusively for cutting food, it is enough to sharpen a knife for about 5 minutes (this is if it is almost completely blunt). The angle of inclination can be taken as minimum.
- If you want to achieve maximum sharpness of the blade, then it is important to sharpen one side until a pronounced burr appears. When they become well visible, turn the knife over to the other side and continue sharpening until the burrs are removed and the blade becomes very thin.
- It is best to use a diamond disc as finishing knives after using an electric sharpener. It is at the fastest time and as accurately as possible removes small notches, making the tool almost perfect for work.
- If you want to upgrade the blade on a sharpener, then experts recommend using standard white EBC circles for this purpose. Their advantage is that they do not burn edges, making the process as delicate as possible.
- When using an electric sharpener, it is important to properly adjust its speed. The optimal figure is about 1.5 thousand revolutions per minute. This is the average value at which you always have time to notice how sharpened the blade, so as not to spoil the material of the knife.
- An important point in the electric sharpening is the timely cooling of the edge. The more it will cool, the less likely the blade will burn. Do not be afraid that during the intensive process the material acquires a purple hue. With proper and frequent cooling, even this is compensated.
The choice of angle when sharpening the type of knife
Angle of sharpening of knives depending on their mission.
Special attention should be paid to the process of sharpening professional expensive knives, as well as individual blades. Since they are of different types, consider the basic rules and tips for sharpening, just on the basis of these types of tools:
- Knives for processing meat carcasses are recommended to be sharpened at an angle of 25 °, and tactical tools - from 25 to 30 °.
- For sharpening professional hunting knives, it is necessary to observe an angle of 35-40 °.
- If you go hunting quite often, then the angle of grinding should be increased to 45 ° - so the knife will serve you sharp much longer than the usual period.
- Special attention deserves the work on the blades reusable razor blades. At the same time observe the minimum angle of the blade during sharpening - about 10 °.
Final sharpening methods
After that, you need to finish sharpening. For this, the fine-grain side of the sharpener is used. The process of removing chipping and giving the knife a final degree of sharpness is called fine-tuning. Lapping on the less aggressive side is carried out according to the same rules as on coarse-grained. After that, the knife is sharpened.
Some alternative ways of final sharpening (finishing) deserve special attention. As a rule, they are used when special sharpness of the tool is needed. Therefore, it is advisable to consider the most inexpensive alternative methods of refinement in more detail.
For sharpening a knife, you can use a small piece of genuine leather.
- Use a small piece of genuine leather. Oddly enough, but such a material is able to sharpen the blade very well. It is advisable to remove the notches with a fine-grained stone, and then proceed with the treatment. First, a piece of skin is wiped from dust and treated with a thin layer of special paste like GOI. Then you need to wait 5-7 minutes until the paste penetrates the pores of the skin, and begin to work. Finishing by this method is done according to the principle “from grain” - that is, the blade of the knife must be kept while working from itself, and moved along the skin in the same way. It is important to turn the blade slightly to the side so that the turning occurs as if diagonally. So the effect will be much better.
- Much popularity for finishing knives recently began to acquire musat. It is a twig of steel on which there are several longitudinal grooves. To grind a knife on it should not like a belt or stone. In this case, the knife remains immovable, while the musat itself leads along the blade. You will not achieve the same good effect as from a piece of leather, but slightly sharpen a knife, which is important.
- A good effect for finishing knives gives ceramics. Used for this purpose most ordinary cheap dishes - a cup or plate that you do not need in the economy. Instead, it is better to take a piece of ceramics separately, which you will always use exactly for this purpose. Sharpening is done in the same way as on a grinding stone. Only it is not the smooth, but the rough surface that is chosen (usually concentrated on the outside of the bottom of the vessel). Otherwise, nothing happens.
Ways to check the quality of sharpening
So, the knife sharpening is complete. But if you want to achieve truly high quality, then you need to check the quality of the work done immediately after sharpening. And what if you have to sharpen the tool a little more? To perform such a check is easy and quite affordable. There are several proven methods for this.
The Japanese technique of checking the degree of sharpening a knife involves the use of paper rolled up into a tube.
- By eye or by touch. In the first case, the sharpened blade of the knife must be brought to a bright light and kept sharp with the edge up: if there are no sharp glare, then the sharpening is successful. If there are highlights, you need to sharpen the tool a little more. Note that glare may not be immediately visible due to the wrong angle of rotation of the knife. Therefore, it is necessary to twist the knife slightly several times to ensure quality. Touch testing is reliable, but not entirely secure. It is necessary to slightly hold the end of the thumb along the blade: if you feel roundness, it means that the tool is not sharpened enough. It is important that throughout the edge of the knife the feeling is the same. And also: in order not to get hurt, try to hold along the blade a little at an angle along the diagonal.
- Not quite common, but quite reliable is the Japanese technique of checking the degree of sharpening a knife. She developed a long time ago by the samurai themselves, who so checked the quality of the katana. To do this, take a newspaper and roll up the tube, after which the tube is wrapped around the 3-4 layers of tape. Then the newspaper is placed on the edge of the table so that with one hand you can hold it to the surface, and the other part, just the one where the adhesive tape is wrapped, hangs in the air. After that, the knife sharply strikes a blow at a small angle on this newspaper: a sufficiently sharpened tool will easily cut the paper into two parts. This method is only acceptable if you decide to make a perfectly sharp knife. For everything else, it does not make sense.
- A common and simple method in everyday life is to check the sharpened knife in the kitchen by cutting some vegetables and fruits. So, tomatoes with a soft, long stale skin are good material for such a check. An insufficiently sharp instrument will not cut such a skin. You can also check the blades of the blades on soft peaches, apples, plums and apricots using the same method.
- Another method is to check the sharpness of the blade on metal cans from beer or plastic bottles. You need to take a knife and hold it with ease on the diagonal. A good tool will instantly cut the bottle, and evenly. But a poorly sharpened blade can either not cut the plastic, or cut it unevenly, forming a lot of burrs. Uneven cutting means that the blade is sharpened unevenly.
- A radical, but also checked for special cases method is to check the blade by the Russian method. For this, a regular thread clings to something above so that it hangs. When the thread stops, having ceased to swing, it is necessary to chop it with a knife at a small angle with a sharp movement. If this happens, then the tool is sharp. But this verification method is appropriate when maximum, dangerous sharpness of the instrument is required.
So, the main points, how to make the correct sharpening of knives with their own hands, are considered.
Depending on which method you choose and for what purpose the knife, you can do the job yourself at home or sharpen the knife on an electric sharpener. But the use of mechanics in this matter in any case will require the help of a specialist.