Mechanical devices for sharpening knives. Knife sharpening tool - an essential tool in the household

Interest in making knife sharpeners with your own hands arises for a reason. The consumer qualities of hand cutting tools are enhanced by the use of modern materials and technologies for the manufacture of the blade and precise factory sharpening. At the same time, the price of the product is also growing, but it is becoming easier to spoil a fairly expensive thing with primitive sharpening. Therefore, various household appliances for sharpening knives are needed not only for convenience. To figure out why a knife sharpener is still needed and how to make it right, you have to start with the ideology and evolution of the knife.

Why you need a sharpener

A living relic of our days is a Finnish hunting knife. Not a bandit finca, sometimes of a bizarre shape, but a Finnish-type hunting knife, on the left in fig. Traditional hunting knives (center and left) are similar in shape to it, but the difference between them is very large.

The blade of a Finnish knife is forged from bloomery iron, which can be smelted right in your yard from swamp ore in a domnitsa furnace, without resorting to the blast furnace process, puddling, and other methods of converting cast iron into iron and steel. The viscosity of bloom iron is excellent, it is very difficult to break a blade from it. But the hardness is also low, somewhere around HRS55, the knife gets dull pretty quickly. Finnish hunters did not care: a blade of such hardness can be directed (sharpened) by beating on many natural stones, and there were always enough smoothed moraine boulders in Fennoscandia.

They sharpen the knife with a beating in much the same way as they beat off a scythe, only the touchstone is motionless, and the blade is moved. First, he is pulled along the donkey with the butt away from himself, then he is turned over and pulled with the butt towards him. The position of the cutting edge (RK) on the touchstone is always dragging; the movements are fast: shirk-shirk! On each movement, you need to keep the contact patch of the blade with the touchstone (see below), but the requirements for maintaining the angle of inclination are not so strict. Learning how to sharpen a knife with a bevel is not very difficult, and with some skill, you can also aim a smoothly running profile at the blade, see below. However, the Finnish knife is, in general, a dead end in the evolution of a cutting tool that has survived in special natural conditions.

A good knife has never been cheap, and in an extreme situation, the durability of the blade, combined with the viscosity of the blade, became vital circumstances. Therefore, even in ancient times, knife blades learned to be hardened from the surface and cemented: the core remained viscous, not brittle, and a hard, hardened crust formed on the outside, see next. rice.:

It is still possible to direct a knife with a cemented blade with a beating, but a skill is needed that is not given to everyone. And the abrasive is already needed from a special breed of stone - lithographic grunstein shale. It is scarce in nature; grunstein is still considered a strategic raw material. There is no artificial grunstein and is not expected. To spoil a cemented knife with an inept chop is as easy as shelling pears - a little somewhere, the cementation bark will be torn off to raw metal (this is not visible to the eye), the knife will only be thrown away, the blade will immediately become dull and will crumble.

Note: if you have an old slightly greenish scythe touchstone lying around somewhere, do not throw it away, it is a valuable rarity.

Knife blades don't need the toughness and toughness of hunting and camping knives, and they should cost a lot less. As a result, special steels and powder metallurgy are widely used in the production of home knives. The blade of the "eternal" kitchen knife is structured like a rodent cutter: in longitudinal layers, the hardness of which decreases from the core outwards. In any case, you have to sharpen the knife less often, but the beating is definitely excluded - the blade from it immediately crumbles.

How do you sharpen a knife?

For these reasons, the push-pull sharpening technology (push-pull sharpening or push-pull sharpening technique) has long been invented:

1. The blade is pushed along the touchstone away from oneself with a twist, holding the butt towards oneself, the position of the RK is running (scraping);
2. Then, without tearing the blade from the touchstone, pull it with the butt towards you with a twist in the opposite direction, the position of the RK is dragging;
3. The blade is turned over and repeat paragraphs. 1 and 2;
4. Pp. 1-3 are repeated, in each cycle reducing the pressure, until the burr formed on the RC comes to naught (does not stick together).

Note: when they say or write “the burr will go away”, etc., this is not true. Metalheads have a slang word for slang; electricians have a “switch”. But in Russian, a burr and a switch are masculine.

Push-pull sharpening saves the blade, but requires high skill from the operator, because. during the sharpening process, a number of conditions must be continuously and precisely observed, see also fig. below:

• Maintain the angle of inclination of the blade to the touchstone, smoothly changing it in accordance with the curvature of the RK.
• Make sure that the tangent to the generatrix of the blade and the transverse axis of the contact patch of the RC with the touchstone coincide.
• Also make sure that the axis of the contact patch is always perpendicular to the longitudinal axis of the touchstone.
• Smoothly change the pressure on the blade as the area of ​​the contact patch changes.

It is very difficult to comply with all these conditions at the same time, completely symmetrically on the forward and reverse stroke of the blade along the touchstone, and a modern knife, as mentioned above, can be damaged by improper sharpening. Any household knife sharpener is just designed to save the grinder from continuous control of at least part of these conditions.

Note: for successful push-pull sharpening, the length of the whetstone (see below) must be at least 2 lengths of the knife blade from shank to tip.

Sharpening profiles

The profile of a knife blade is linked to the properties of the material and the structure of the blade, as well as to the properties of the materials for which the tool is intended to be processed. Sharpening on a simple blunt wedge (pos. 1 in the figure) gives a stable but rough blade: cutting resistance is high, and the knife tears quite viscous materials. A sharp wedge (pos. 2) quickly becomes dull or chipped; on viscous and / or fibrous materials, the cutting resistance may be greater than a blunt wedge due to the friction of the cut against the blade.

Ideal in all respects is an animated (smoothly escaping) profile, pos. 3. Experts are still arguing which generator is better - evolvent, hyperbola or exponential. But one thing is indisputable - it is difficult and expensive to make an ogival blade under production conditions, and it is impossible to direct it yourself. Therefore, knives with ogive sharpening are used only in special equipment, for example. microtomes - biological devices for obtaining the thinnest tissue sections.

For disposable blades, e.g. blades of safety razors, faceted sharpening is used, pos. 4, i.e. An ogive generatrix, as mathematicians say, is approximated by line segments. The number of sharpening edges is indicated in the certificate or on the manufacturer's website. For thick coarse bristles, 3-4-faced is better; for delicate hair not on the face - 8-sided. Universal is considered 6-sided.

Angle α

The sharpening angle is always given in half the value of α, because many tools and, for example, bayonet-knives, are sharpened on one side. For knives for various purposes, the angle α is maintained in the following. limits:

• 10-15 degrees - medical scalpels, straight razors, knives for artistic carving.
• 15-20 degrees - confectionery (for cakes) and vegetable knives.
• 20-25 degrees - bread and fillet knives.
• 25-30 degrees - hunting, camping, survival knives.
• 30-35 degrees - general purpose household knives.
• 35-40 degrees - carpentry tools, shoe knives, axes.

One and a half

Sharpening knives, except for special ones, is done almost exclusively with a one-and-a-half profile, on the left in fig. One-and-a-half sharpening is so named because the flat edge of the blade (descent) is formed during the manufacture of the blade and cannot be sharpened. In fact, guiding a knife with one and a half sharpening is no more difficult than sharpening a simple wedge. One and a half sharpening is optimal for a knife that works with a variety of materials, and it is much easier to make a knife sharpener with one and a half sharpening than for faceted sharpening.

In the center and on the right in Fig. the stages of sharpening the blade and the numbers of abrasives used on them are shown. The abrasive number corresponds to the number of its grains per 1 sq. mm surface. The finishing stage has some features:

1. Hunting and camping knives are not brought. So it is easier to cut hard (eg, bones) with a broach (with filing) with them. In addition, if you accidentally cut yourself, then a slightly lacerated wound stops bleeding faster, heals more easily, and there is less danger of infection entering it.
2. The blades of dangerous razors, shoe knives and for artistic carving after abrasive are brought to a mirror smoothness on a leather whetstone with GOI paste.
3. Guiding and finishing the blades of kitchen knives can be reduced to one operation with abrasive No. 800-1100.

Touchstone

A home-made knife sharpener will be much more convenient and accurate if you don’t buy a donkey for it, but make it from a piece of a square professional pipe 200-300 mm long (on the left in the figure below) or a wooden bar.

The edges of the base are pasted over with emery cloth acc. numbers. Glue - clerical glue stick. The advantages of a skin-based touchstone are obvious:

• Much cheaper than an emery bar.
• It can be made on 4 abrasive numbers, while emery stones are maximum 2-sided.
• Wear (development) of the abrasive is possible no more than the thickness of the abrasive layer of the skin; the waviness of the RK due to the rotation of the touchstone on the sharpener rod (see below) is also no more than this value.
• As a result, the error in the angle of sharpening from the development and rotation of the touchstone does not exceed fractions of a degree.
• The whetstone from the pipe can be put on a threaded rod (in the center in the figure), which speeds up and facilitates the change of abrasive.
• A whetstone made of a pipe or a wooden block is held in any clamps for an emery block no worse than the latter, on the right in fig.

Knife sharpeners

The simplest manual knife sharpener is an angular frame in which a whetstone is clamped, pos. 1 next. rice. The same type of “company” is on sale, and this is marketing, marketing: for a plastic board with inclined sockets for donkeys, they want up to $50 or more. Touchstones - non-standard sizes; Ordinary holes won't fit. Worked out - you need to buy the original ones. Price - you know. And all the convenience - when sharpening, keeping the blade strictly vertical is still easier than maintaining its angle of inclination.

The use of the simplest knife sharpener can be further simplified to a complete absence of the need for skills, if it is supplemented with a sliding shoe with a magnetic knife holder, pos. 2. The order of sharpening in this case is the following:

1. The knife is held by the handle with the right hand, turning in the direction of travel according to the curvature of the blade;
2. With the fingers of the left hand, except for the big one, they press the shoe to the touchstone;
3. With the thumb of the left hand, they press on the butt of the blade, pressing the RC to the abrasive.

The function of maintaining the angle of inclination is removed from the operator, and the rest are distributed to 2 hands. In this case, the skill of sharpening with one's own hands is developed immediately, but a holder is needed that firmly holds the knife and at the same time allows it to slide over its surface. This can be done from the magnets of the carriage drive of the write-read heads from an unusable HDD drive (hard drive). The “screw” carriage drive magnets are niobium, thin, flat, smooth and very strong (shown by red arrows in pos. 3). They are glued with DIFFERENT poles on a steel strip, the force of attraction of the blade will then double. And to ensure sliding, the holder is covered with a fluoroplastic film 0.05-0.07 mm thick. PET from bottles will also work, but it is thicker and the attraction will be weaker. Polyethylene is not suitable, it will be wiped immediately.

Note: remember this holder, we will need it later.

LM

It does not require any special skills and the use of a manual sharpener for knives such as Lansky-Metabo, pos. 1 in fig. The scheme of its device is given in pos. 2, and the order of use - on pos. 3. The disadvantage of the Lansky-Metabo sharpener is the instability of the sharpening angle along the length of the blade: a rod with a whetstone is driven along it. The offset of the touch point is constantly changing, because it describes an arc of a circle, and the blade has a different configuration. Resp. "floats" and the corner. Therefore, the Lansky-Metabo sharpener is mainly used for sharpening hiking and hunting knives with a relatively short blade.

However, this disadvantage can be turned into dignity if the blade is clamped in the terminals with the root part A (near the handle) and the tip slightly turned away from you, pos. 4. Then, at the root of the blade, the sharpening angle will be the largest, which is optimal for processing hard materials or using the knife as a cleaver. So after all, they work in such cases, so that the outer arm of the arm-blade lever is shorter.

Towards the middle of the blade B, the sharpening angle will gradually decrease and reach a minimum at the bend of its generatrix B1, which is convenient for fine work. Then, towards the B tip, the angle will increase again, which will make the tip more resistant to drilling, gouging/impact and breakdown (piercing).

Note: Another disadvantage of the Lansky-Metabo sharpener is the difficulty of execution in the desktop version. But this shortcoming, as they say, is fake, see pos. five.

Detail drawings of the original Lansky-Metabo sharpener are given in fig. The numbers at the windows for the bar (guide) correspond to the FULL sharpening angles.

On the trail. rice. an assembly drawing of the clamp is given, and then - the drawings and dimensions of the Lansky-Metabo terminals, made from a corner 90x90x6 mm. The author of the development hides under the pseudonym Serjant. It is certainly a matter of his modesty. But, by the way, in production, technological innovations that make it possible to use standard profiles for the manufacture of shaped parts are sometimes valued more than serious inventions.

Note: on the trail. rice. given the assembly drawing of the sharpener Serjant. As for the inconvenience of fixing in a vice - see above.

Knife sharpening machine

The most advanced household manual sharpener today is the Apex type knife sharpener. Its appearance, device diagrams and how to use it, see fig. Apex can be made with a continuously variable sharpening angle (pos. 2) or fixed angles like Lansky-Metabo (pos. 3). Normally, they work on Apex as on Lansky-Metabo (pos. 4), but other options are possible for more accurate sharpening, see below.

A homemade version of the Apex sharpener - a sharpener for knives Skomorokh

In 2016, in Runet, it made a noise, perhaps, no less than once the bubafonya stove, the desktop modification of Apex by Ivan Skomorokhov, see fig. on right.

Skomorokh sharpeners are much simpler than the prototype and in no way inferior to it in functionality.

How to make a knife sharpener Skomorokh, see video:

Not only knives...

The original Apex sharpener is not very suitable for sharpening carpentry tools - chisels, planer irons. Apex's sharpening angle floats for the same reasons as Lansky-Metabo. Meanwhile, if the angle of sharpening the chisel along the width of the blade “walks” by more than 1-1.5 degrees, then the tool strives to go sideways, crawl out or go deep into the solid wood along its fibers. It is very difficult to choose a groove for a spike / comb evenly and accurately with such a chisel.

There are special devices for sharpening carpentry tools, about which a special conversation is needed. Homemade products like a roller cart sharpener, see fig. on the right, rather curiosities: not to mention the complexity, they require a stone or steel table, and, most importantly, they do not guarantee against misalignment of the blade on the whetstone, which leads to the same undesirable result.

Meanwhile, 2-3 years ago, in one of the Chinese magazines on technical creativity, Apex’s refinement flashed for sharpening, not inferior to that on a factory electric grinding semi-automatic. The alteration is not difficult, see Fig.: the bar is set horizontally according to the level and the horizon of the bar is held along it, leading to sharpening. Within the angle of rotation of the rod in the horizontal plane of 10-12 degrees to the right and left, the sharpening angle error is less than 1 degree. If the extension of the point of contact is from 250 mm, it is possible to sharpen chisels and pieces of iron planers up to 120 mm wide.

In this mode of operation, zero (theoretically) sharpening angle error can be achieved by keeping the bar stationary and moving the knife held by the magnetic holder, see above. Thus, it is also possible to sharpen the irons of shaped planers, if a round cross-section, semicircular, elliptical or segmental whetstone is placed in the clamps. The main thing is that the touch spot should always be a point.

...but also scissors

Another refinement of the Apex sharpener for sharpening scissors (also a necessary thing in the household) is shown in fig. on right. Total work - a couple of pieces of a corner or scraps of galvanization and 4 additional holes in the sharpener table. About the process of making do-it-yourself attachments for sharpening scissors to the Skomorokh sharpener, see next. video:

Video: sharpening scissors, attachment to the sharpener Skomorokh

One last thing about scissors

Before grabbing badly cutting scissors and sticking them in the sharpener, check to see if the hinge is loose. Open the scissors and look at them from the side. See how the tip is wrapped with a screw towards each other? That's why scissors cut: the point of contact of the blades during cutting shifts from the roots to the ends. And therefore it is difficult to cut with scissors with the left hand: the inversion of the ends is designed for the kinematics of the right. And if the hinge of the scissors is loose, the blades will move away from each other and will not even cope with paper. In this case, you just need to tighten the riveted hinge with a hammer, and the screw hinge with a screwdriver.

Almost every person in life is faced with the question of sharpening knives. After all, any knife, regardless of its quality, sooner or later becomes dull. Therefore, the blade must be carefully looked after.

In stores today you can choose any sharpener among a huge variety.

What are sharpening stones?

In general, there are several main types of such devices. Namely:

Oil, on the surface of which there is oil, especially to save material.

Water, similar to the previous one, but water is used here.

Natural, industrially processed.

Artificial, made from non-natural materials.

Rubber, extremely rare. Completely inconvenient to use.

Nuances in the issue of sharpening

There are moments in sharpening every knife.

For example, a Japanese self-sharpening type requires special attention from a rather experienced specialist, since the Japanese type of steel is quite fragile. To sharpen them, manufacturers give a recommendation to use different water stones, endowed with a variety of grain sizes.

Mistresses use sharpeners bought in the store for sharpening. When using several knives, their sharpness lasts longer.

But this is very important, even though it takes a lot of time and effort.

How to sharpen knives properly?

For this, special conditions must be created. Thanks to them, the knife will remain sharp for a very long time.

Therefore, it is important to choose the right angle at which you will sharpen your knives. According to the basic rule in this matter, the smaller the angle at which the knife is sharpened, the stronger the cutting edge will be.

It is important not to forget that the next sharpening depends on the maximum sharpness. The sharper the knife, the faster it will need to be sharpened. At the same time, it will be much more difficult to make it “workable” again.

Why sharpen knives?

The purpose of sharpening is to restore the sharpness of the blade. To do this, take care of the correct sharpening angle. That is, it is necessary to restore the previously set angle that meets the standards from a technological point of view.

To check how well the sharpening is done, cut the material that is cut with the blade of this particular knife. If the material is cut elementarily, you will do everything absolutely right.

Possible problems during the sharpening process

In order to choose the right angle correctly, it is important to have some experience, without which it is quite difficult to cope with this issue. And even more so if there is no special equipment for this.

After all, if you hold the knife with your hands during the sharpening process, it is quite difficult to achieve its ideal “sharpness” as a result.

How do you sharpen knives at home?

Sometimes it happens that the knife needs to be sharpened quickly. A block of wood, a hacksaw, sandpaper, a ceramic plate, a chisel, etc. can come in handy here.

And there are even those who can sharpen on the foundation of cement with sand. But, this method is not recommended at all. After all, there are many other and more proven ones!

The best of all is to make a homemade device. It is not only convenient, but also indistinguishable from the factory.

How to sharpen a planer knife

An experienced professional master who has not only knowledge, but also skills in this matter can handle knives of such a plan. The process is quite complicated actually.

At the same time, in a simple store, equipment for sharpening such a knife is quite difficult to find. You should know that a modern tool will help here, in which you can set low speeds with water cooling.

It is necessary to apply a new stone on which a flat surface. The best will be exactly the water type of stone.

In addition, without having certain experience and skills in sharpening planing knives, you can also contact the service station, where you probably have equipment such as a sharpener.

No matter how hard you try, the knife will still get dull. One wise parable says that if you do not sharpen the tool, you will have to exert force when using it. This is especially true for knives. If they are not sharpened, then we can say that there is no owner in the house. To keep them in constant readiness will allow a device for sharpening knives. There are several varieties of them. Which is better to choose and which is easier to use? This will be discussed in the article.

How to sharpen a knife

The tool that is used to sharpen knives can be divided into two large groups:

• manual;
• mechanical.

Each one is suitable for a specific application. If there is a large turnover, when hundreds of knives need to be sharpened, then there is no point in a handmade product, a special mechanical machine will be needed. The latter can be both domestic and professional. Depending on the surface used in knife sharpening machines, they are divided into:

• natural;
• ceramic;
• with diamond chips.

Each of these types is better suited for its type of knives. For example, products with a ceramic blade are highly reliable and sharp. Such devices can cut products with surgical precision. Sharpening a ceramic knife is performed by a machine with the same element. Knives for household and professional use made of metal are most often sharpened using natural materials, which can be slate and corundum rocks. Their use is impossible without wetting, which improves contact and reduces the likelihood of damage to the blade.

Grindstones vary in grit. It is indicated by a number that starts from 200 and ends at 12 thousand or more. The higher the grit, the more accurate the sharpening will be. In professional sharpening, several stones with different grain sizes are often used. Sharpening starts with a rough grid and ends with an argument at the minimum grit. In this case, the blade can shine like a mirror.

Musat

Those who take the musat in their hands for the first time do not immediately understand what kind of device it is. It is a kind of round file with small notches on the working surface. This tool makes it easy to sharpen a knife. But for this it is important to know some secrets. The blade that needs to be sharpened rests on the table. In this case, the knife must be firmly held by the handle. Musat movements should be arcuate. Their orientation should be from the handle to the tip. In this case, it is necessary to observe the angle of 25 degrees. Each side of the blade is processed separately, which requires some skill.

Note! Musat is used to sharpen a knife. If the product is already too dull, then you must first apply a different sharpening method.

Bar

Often whetstones for sharpening are called boats. They are used not only to correct the cutting part of kitchen knives, but braids and other items. These bars are sold with different grits, but for home use it does not matter much. There is a certain algorithm that should be used when servicing the working cutting part. For a professional approach, you still need several bars with different grain sizes. They need to be prepared in advance. A special oil is supplied with high-quality sharpeners, which must be applied before starting the process.

It is desirable that the block that will be used for sharpening is fixed on the table, then there will be no problems following the step-by-step guide on how to sharpen the knife. The sharpening angle that is best suited for a particular product is selected. During sharpening, it is necessary to hold the knife at an angle that will be equal to half the selected angle. For ease of holding the angle, there are special devices. During the process, do not put too much pressure on the blade, as this will not speed up the process, but may have the opposite effect. Hand movements should be smooth with the same pressure on each step.

It is necessary to move the product away from you, while the sharp side must be kept not in the direction of the body. Hold the knife must be perpendicular to the bar. In this case, when it comes to the rounded part, the device must be slightly shifted, as can be seen in the illustration above. It is important that the surface of the blade constantly remains on the stone and does not break off from it. This can lead to the fact that sharpening will have to start over. To achieve this, the correct choice of the length of the stone will allow. It should be larger than the size of the blade, preferably twice. The process must be carried out until a slight inversion of the edge on the reverse side is noticeable. This twist should be uniform over the entire surface. When the goal has been reached, you can turn the knife over and continue processing it on the other side.

When both sides of the blade are finished, it is necessary to replace the stone and repeat the procedure. But in this case, you should only move the blade away from yourself. This should be done until the last bar with the finest abrasiveness is used. The end result can be seen on the mirror surface of the blade. It is worth remembering that with each change of stone, the angle should be observed, and the pressure should be reduced. This will extend the life of the stone. Additionally, the blade can be polished using pastes and special compounds.

Machine

Sharpening on a special electrical appliance that is used in everyday life is not particularly difficult. In this case, the stones are located at the required angle and it is enough just to pass the knife through a special slot. Working with a professional machine requires special skill. This is due to the fact that it is required to withstand not only the angle of the blade, but also the pressure. It must be the same. It is also important to feel the level of heating of the blade. It should be the same around the entire perimeter of the product. If the knife is overexposed, this will lead to damage to the structure. Professional models are equipped with stones with different grain sizes, which require wetting with water or oil. Assembling a machine for sharpening knives with your own hands is not so difficult. The process is described in the video below.

Choice of sharpening angle

For high-quality sharpening, it is necessary to choose the right angle, which is determined by several factors. It is influenced by the material from which the knife is made, as well as where the product will be used in the future. If it is necessary to achieve the sharpness of a scalpel or straight razor blade, then a slope of 10 degrees must be chosen. When it comes to a regular knife that is used in the kitchen, then you should choose a slope of 20 degrees for it. This angle is universal. Meat and fish require a fairly sharp tool, so a 15-degree angle is ideal for it. Hunting knives require sharpening with a slope of 25 degrees.

To get the required angle, you can perform a simple operation. If a square sheet is bent in half, then the diagonal line will be at an angle of 45 degrees. With subsequent bending, the angle of the line will be halved.

Sharpening a ceramic blade

A ceramic blade also requires a knife sharpener. This is contrary to what someone claims they are never dumb. Not so long ago, such devices became widely available and fell in love with housewives. The service life of such a product is at least one year, after which it requires service. The blade maintenance process follows the example described above for the manual method. But it should be understood that a ceramic product requires less pressure, as well as a large grain size of the stones. If there is a desire to learn, then it is better to use an old knife, because one wrong move will render it unusable.

Summary

As you can see, the process of maintaining the blade is quite complex and requires some skill. But everything can be learned if you follow the steps described. You can start with unnecessary blades that have been in the pantry for a long time. Let them become a training base. When working with a sharpening machine, it is important to use various protective equipment and never be in the plane of rotation of the disk, as serious injury can result if it fails.

The service life of any knife directly depends on the methods of its operation and the procedure for sharpening the blade. Devices for sharpening knives are so diverse that they allow a modern person not to resort to the work of specialists, but to do all the work on their own at home. To sharpen knives, you can use both a special industrial-made device, and any device made by yourself. It is important to know that simple elements for sharpening knives (for example, a whetstone) that are at hand can do a bad job and the sharpness of the product will not only not return, but gradually the product will completely become unusable. Moreover, any home-made device for sharpening knives can be based on the use of these very simple sharpening devices. Detailed information on how to make a sharpener with your own hands can be found below.

A home-made manual knife sharpening machine, subject to all the requirements for its creation, will simplify the sharpening of knives and its performance will be no worse than a professional one. Proper sharpening includes the following rule: each type of cutting product has a certain edge sharpening angle, which must be constant along the entire length of the blade (see table No. 1). The sharpener, which will be initially based on this principle, will give the master a sharp knife edge for a long time.

Table No. 1. Sharpening angle in parallel with the type of cutting device

Edge processing during sharpening should be even. To fulfill this condition, the following rules must be observed:

• the blade must be fixed in the vise of the fixture reliably and efficiently, without exposing the metal of the blade to damage;
• the movement of the touchstone along the axis of the knife edge must be uniform and strictly at a certain angle;
• the point of contact of the blade must be strictly perpendicular to the longitudinal axis of the sharpener;
• the pressure on the knife blade should change smoothly depending on the change in the contact area between the blade and sharpener.

Simple knife sharpener

The simplest device for sharpening knives is based on the use of an angle frame and a whetstone. The price of such a primitive factory-made device is quite high, as is the price of interchangeable whetstones, while making such a device for sharpening knives at home will not be the slightest difficulty for the master. You will need the following inventory:

1. Wooden blocks of the same size - 4 pcs.
2. Drill (or any other drilling tool).
3. Bolts and nuts (about 4 pcs.).
4. Touchstone.
5. Protractor.

First you need to make a pair of wooden corners, placing the bars to each other strictly at an angle of 90º (Fig. 1). Close the resulting wooden corners with each other in parallel as a whole and drill holes through the diameter of the bolts. Insert bolts into the holes, and tighten the corners a little to each other with nuts.

The point of this invention is to be able to sharpen simply by holding the knife vertically in relation to the sharpening surface located at a given angle.

The most important thing is to correctly fix the donkey between the wooden corners of the fixture. To do this, using a protractor, you need to set the desired angle of inclination of the touchstone and tighten the bolts tightly to clearly fix the position of the touchstone.

With some refinement of the fixture, it is possible to fix the position of the knife relative to the grinding stone. A significant disadvantage of such a machine for manual sharpening is the impossibility of smoothly adjusting the angle of inclination of the grindstone.

Sharpening device from mounting brackets

The diagram and drawings of a homemade knife sharpener from mounting brackets, based on the Lansky fixture, are clearly shown below.

To assemble this device you will need:

1. Metal corners 90*90 mm with a wall thickness of 6 mm.
2. Stud with thread M6 and length 160 mm.
3. Thin rod (electrode, needle, etc.).
4. Touchstone.
5. 2 rectangular pieces of metal (sponges for clamping the donkey).
6. Pliers.
7. Hacksaw for metal.
8. File (or any other tool for processing sharp corners).
9. A set of hardware (nuts and bolts).

In both metal sponges intended for fixing the donkey, you need to drill under the connecting bolt. Fix the donkey. A thin smooth needle, previously bent at an angle of 90 º, must be inserted and fixed in the hole in one of the jaws. In the future, with the help of this lock in the form of a knitting needle, a certain angle of inclination of the touchstone will be set. Such a device for sharpening knives is characterized by an extensive coverage of the sharpening angle, which, no doubt, will be of interest to most craftsmen.

Machines with fixed blades

Machines for sharpening knives with fixed blades will attract the attention of those people who want to sharpen a knife not only qualitatively, but also quickly. The design, which rigidly fixes the knife blade relative to the grinding stone moving at a set angle, allows you to accurately set the angle of inclination.

To create such a homemade machine with your own hands, you will need:

1. The base is a rectangular wooden plate with dimensions of 440 * 92 mm and a thickness of 18 mm.
2. Wooden plate 92 * 45 * 45 mm (for fixing a vertical threaded stud).
3. Wooden block 245 * 92 mm and 18 mm thick (plate to which the knife will be attached).
4. Iron plate 200*65mm and metal thickness 4mm.
5. Piano loop, 92 mm long.
6. Hairpin M8 325 mm long.
7. Nuts and bolts with M8 thread.
8. Drill 6.5 mm.
9. Tap M8.
10. Self-tapping screws 50 mm, 4 pcs.

A die designed to fix a vertical threaded stud must be drilled through with a 6.5 mm drill. The hole should be located at a distance of 15 mm from the edge of the plate, approximately in the center.

Further, in the resulting hole, it is required to cut the thread for the M8 stud. A wooden plate prepared in this way must be screwed to the base at a distance of 265 mm from the edge using ordinary self-tapping screws 50 mm long, screwed into the back of the base.

After securing the wooden part of the restraint, you can proceed to attach the iron plate. In the center of the plate 200 * 65 mm, an oblong groove should be drilled, 90 mm long and about 1 cm wide. The groove should be located at a distance of 60 mm from the edge of the clamping plate. Additionally, it is required to drill a hole at a distance of 20 mm from the opposite edge and cut a thread in it for an M8 bolt. Then you need to attach the clamping plate to the previously prepared wooden base using this bolt. Using another bolt and a suitable washer, it is necessary to fix the clamping plate in the center of the cut groove. The fixation should be clear, but at the same time neat, so as not to damage the surface of the blade.

The most difficult part of assembling this fixture is preparing the adjusting device that will set the angle of sharpening the knife. For this you will need:

• metal square profile 40×40 mm;
• furniture bracket, 40 mm wide;
• a pair of rivets;
• plywood block 42 × 25 and 18 mm thick;
• bolt and nut M5;
• a pair of wing nuts M8;
• touchstone;
• steel bar with a diameter of 0.8 cm and a length of 40 cm.

A pair of holes must be drilled on a plywood bar: a through hole with a diameter of 8 mm along a section of 42 × 18 mm (the distance from the edge along the side of 42 mm is set at 15 mm) and a through hole with a diameter of 5 mm along a side with a section of 42 × 25 mm (distance from edges 10 mm). The square pipe should be cut in half so that a “U”-shaped bracket with a width of 40 * 15 mm and lugs of 20 mm is obtained. In the ears, you need to drill 8 mm holes, into which the M8 pin will be inserted later. Connect the resulting bracket to the furniture hinge using rivets. To the resulting structure, using the second part of the furniture bracket, tighten the plywood bar with an M5 bolt.

Connect the touchstone to the guide rod, which is a steel rod with a cross section of 8 mm. When connecting the touchstone and the guide rod, you should strictly ensure that their center lines coincide. If desired, for the convenience of using a sharpener, a handle-holder can be adapted to the touchstone on the reverse side. It remains to fix the donkey in the guide mechanism, fix it with a lamb and a home-made device for sharpening knives is ready.

Machine tools with fixed sharpening surfaces

Machines with fixed sharpened surfaces are a simple modification of a device for processing household knives. In such a device, there is no possibility of adjusting the sharpening angle, while several different angles can be set in advance for sharpening different types of knives. The work of sharpening blades with the help of such machines is not difficult, it is enough just to drive the blade along the abrasive surfaces in the recess.

The device consists of a pair of planes inclined to each other at a certain angle, one of which is a grindstone.

Electric knife sharpeners

The procedure for creating an electric sharpening machine is simple: it is enough to supply almost any device for sharpening knives and scissors with an electric drive. Such a sharpening machine allows you to quickly and accurately sharpen the product and at the same time provides a better concave shelf at the edge of the blade.

The mechanism of the electric sharpener for sharpening knives contains a guide, which is placed along the axis of rotation of the whetstone, and with the help of which the blade is adjusted at a given angle. The sharpening angle is set and set by the guide, and the clamping force is determined by the master.

Particular attention must be paid to the speed of sharpening, because. the electric drive allows you to sharpen the product at high speed, as a result of which the surface of the knife heats up. Such surface heating leads to the tempering of hardened steel, as a result of which the knife can quickly lose its hardness and its service life will be noticeably reduced. To prevent steel tempering, sharpening on a high-speed electric sharpener should be performed at short intervals and with sufficient breaks to allow the knife to cool.

Making stones for sharpening

It will not be difficult for a modern master to make stones for sharpening with his own hands. For this you will need:

• a wooden plate according to the size of the future grindstone;
• epoxy resin;
• cardboard box according to the size of the bar;
• abrasive;
• protective rubber gloves.

As an abrasive, you can use ready-made powder, or you can prepare an abrasive of your own production, for example, from an old Soviet-made green bar. Such a bar can be powdered and used later as an abrasive.

A wooden plate needs to be processed on one side with sandpaper and a saw to make frequent notches. Epoxy resin mixed with abrasive crumb. Having previously placed the bar in a cardboard box glued to the size of the bar, cover the prepared surface of the wooden bar with a mixture of epoxy and abrasive. After complete curing of the resin, the bar is ready for use.

Another option for making sharpening stones with your own hands is to create a whetstone from small rectangular glass plates about 5 mm thick. Using double-sided adhesive tape, sandpaper is glued to the surface of the glass plate. The whetstone is ready to go.

Tool for sharpening wood blocks

A simple device for sharpening knives is a tool consisting of a pair of wooden slats and a pair of bars with abrasive, with the same geometric dimensions.

Wooden slats should be carefully sanded with abrasive skins. Then, after applying auxiliary markings, depending on the angle of sharpening the knife, make cuts to a depth of 15 mm. Insert emery bars into the resulting holes so that each groove matches, and then fasten them with bolts. To give the grinding device greater stability, the lower part of the surface can be laid with a piece of rubber.

Types of devices for sharpening cutting tools are different and each master will be able to choose the manual machine that will fully satisfy his needs.

To perform their functions, knives must always be sharp. Any housewife, using a knife for cutting food, knows how quickly it becomes dull.

Can make sharpening from wooden blocks. You will need 4 bars of the same size: 2 - wooden, and 2 - abrasive. The wood is sanded, removing all burrs with sandpaper. Markings are applied to them depending on the desired angle, a grindstone is applied to them and its width is fixed. On the markup, cuts are made with a depth of 1.5 cm. Abrasive bars are inserted into the recesses and fixed with bolts.

Consider the action of the clamping device. The knife is fixed and remains motionless, and the stone makes forward movements. It forms a cutting even edge on the edge of the knife at the required angle. To make the blade perfectly sharp, you need to consistently change the grinding stones. It must be remembered that the stones must move strictly perpendicular to the area that is being sharpened.

Chisels and planer knives can be sharpened at home. It is necessary to make an elementary fixture, where the sharpening angle will be fixed. Sharpening is carried out strictly on sanding paper.

Simple knife sharpening machine

For its manufacture, two pairs of slats and a bar are needed. The slats are connected to each other with adjustable screws, a bar is installed between them. The design must be stable, it is undesirable to move it around the desktop. To better fix the bar, it is necessary to provide support strips that can be placed between the wooden components.

Easy to do with your own hands. You need to prepare the right tool.

Such a machine has disadvantages:

• it is not always possible to control the sharpening angle, especially if you work for a long time;
• the design is unstable, another fixation unit is needed;
• you need to regularly tighten the screws so that the location of the bar does not change.

Sharpening planer knives

This is a complex process that requires certain knowledge and skills. It is difficult to find a device for sharpening planer knives on sale. Many do this on regular sharpening. It is recommended for this case to purchase a modern low-speed sharpener, which is equipped with water cooling.

To make a planer knife sharp, you need to find a smooth and non-greasy stone that is used in this area. Water stone is perfect.

You can sharpen such a knife in any car workshop where there is a tool for sharpening knives. For an additional fee, any blade will be sharpened using a special machine.

There are two types of knife sharpening.: single-sided and double-sided. Working methods will differ from each other. This must be taken into account.

When choosing a quality bar, you need to take a stone with an average grain.

Knives that have special cutting edge coatings do not need to be sharpened. They are made of extra hard alloys that protect the blade from wear.

A sharpener with a special cutting edge in the form of teeth should not be sharpened in the usual way. For such a blade, you need to use laser control, which is not in an ordinary apartment.

It is often impossible to wash the blades with hot water, as this will dull their blades faster.

To quickly sharpen a blade, without having a special tool at hand, use a regular ceramic mug. Its bottom usually has a rough rim not covered with glaze - it can be used instead of stone. The method is suitable for auxiliary subsharpening.

In some villages they still practice method of sharpening blades on the foundation. For its manufacture, a cement-sand mortar was used, so the surface of the foundation has a granular surface. Of course, this method cannot be called acceptable for residents of apartment buildings, but this is a pretty good option.

Conclusion

Every home should have a knife sharpener. A simple model of a device for sharpening knives can be made by hand.

Let it be the simplest model, but if it is made by hand, your blades will never dull.