Any knife, even the best one, requires careful care. If you neglect this, then over time it may stop cutting. Therefore, it is important to choose the right knife sharpening device. Currently, you can find a huge number of stones and sharpeners in stores.

Types of sharpening stones

There are mainly three types of sharpening stones:

Features of sharpening various knives

To sharpen Japanese knives yourself, you must have sufficient skills in this area. After all, Japanese steel is very brittle, so it requires special care behind you. Manufacturers recommend sharpening such knives on Japanese water stones. It is advisable to use several stones with different degrees of grain at the same time, which will help maintain the sharpness of the knives for a long time. Of course, this process is not easy and requires patience.

But to sharpen a kitchen knife, everyone is used to using a special sharpener. With its help, you can quickly and conveniently make any knife sharp. Of course, no housewife would want to use several stones for sharpening. However, thanks to their use, the knife will cut much better.

Conditions for sharpening

Choosing and purchasing a device for sharpening knives is only half the problem. It is necessary to ensure that the knife remains sharp for several months. To do this, you should choose a favorable angle for sharpening. Some believe that the smaller the angle between the edges of the blade, the sharper the tool will be. But this is not entirely true, since such an action can lead to the fact that the knife will soon lose its cutting qualities again. That is, the sharper it is after sharpening, the faster it will become dull. In this case, a pattern can be identified: the smaller the angle at which the knife was sharpened, the less strength the cutting edge of the blade will have.

Sharpening task

The main objective of this operation is to restore the sharpness of the blade. At the same time, the correct sharpening angle must be maintained. Therefore, we can say that in its process the angle that was set earlier is restored. This angle must fully comply with all technological standards. The task is completed if the knife can be used to cut the material for which it is intended.

What problems may arise during the work process?

Of course, choosing the right angle for sharpening is difficult. Moreover, such a process is difficult if there is no special device for sharpening knives. After all, if you hold the blade with your hands, it will be very difficult to achieve a uniform sharpening with right angles. To eliminate this problem, you can use a homemade knife sharpening device. Moreover, making it at home is not difficult. And although there are currently a huge number of different sharpening devices, their design is not particularly complex, so it will take little time to manufacture such a device.

How can you sharpen a knife at home?

One of the main tasks of every man around the house is sharpening knives. Making your own device is not only convenient, but also effective. In this case, you can independently make a device that will resemble the factory one. You can also use some available tools:

• Hacksaw.
• Wooden block.
• Chisel.
• Sandpaper.
• Plane.
• File and the like.

In some villages, it is also practiced to sharpen knives on the foundation. It is made from cement-sand mortar and has a grainy surface. Of course, this method cannot be called an example to follow. But if you urgently need to sharpen a blade, and there is no device for sharpening knives, then this is a relatively good option.

Why are drawings needed?

Knife sharpeners are inexpensive. Nevertheless, many owners want to make a device for sharpening knives with their own hands. Such a device will be of higher quality than a store-bought one, since in the process of its creation only natural materials. In order for the production of a sharpener to be completed successfully, it is necessary to carry out the process according to the proposed plan:

• Purchase or make your own drawings for clamping jaws. It is very important to draw in detail future design. Particular attention should be paid to small details.
• Draw a drawing of the left and right stop, which is necessary to ensure that the assembled structure does not fall apart.
• Prepare a drawing of the guide. There are several nuances here.

Guide drawing: features

To make the guide the right size, you should:

As you know, there are two main types of knife sharpening: single-sided and double-sided. Naturally, the methods of work in one and another case differ from each other. When working with knives, the following factors should be taken into account:

Sharpening planing knives

Sharpening planing knives is quite difficult process. To complete it, you need to master some knowledge and skills. A device for sharpening planing knives is difficult to find on sale. Therefore, many improve their cutting qualities using conventional sharpeners. But for this you need to acquire a modern low-speed water-cooled sharpener. To easily sharpen a planer knife, you should find a smooth and ungreasy stone used in this area. Better to use water stone. You can find a sharpener in car workshops, where they can sharpen any blade for an additional fee.

A DIY knife sharpener will be very useful in the household.

With the help of fairly simple ones, you can carefully and safely sharpen cutting tools, which is simply necessary in the kitchen, fishermen and hunters, and in the workshop.

Of course, a wide range of sharpeners are offered in stores, but homemade devices will save you from unnecessary costs.

A dull knife is a torment for the housewife when she slices bread, cooks food, or cuts meat. Cutting with them is not only difficult, but also dangerous, because... exactly blunt instruments are more likely to cause injuries. There is no point in proving the need for a sharp blade for a fisherman, hunter, shoemaker, etc. It is absolutely clear to everyone that a knife requires periodic sharpening. Another thing is how to provide it.

Many people use tools such as abrasive stones, emery wheels and sandpaper, files. Most often, abrasive or grinding stones are purchased for these purposes, and the procedure itself is carried out “by eye”. After such sharpening, the knife becomes sharp, but also dulls quite quickly.

Why is this happening? The knife blade is made of various steels, has different thicknesses and sharpening parameters. The process of high-quality sharpening should completely restore the shape of the blade, and only in this case will its sharpness meet the planned standards.

Ensuring uniform sharpening without fixing the position and guide elements is very difficult even for professionals. The task is much easier when using special devices that allow you to stabilize the processing mode (loads, directions, speed).

To mechanize rather labor-intensive work, it is better to use appropriate sharpening machines. Both devices and machines can be made with your own hands.

Basic principles of sharpening

When properly sharpening a knife, the basic condition must be met: forming a sharp edge of the blade while maintaining its shape, which is ensured by removing metal at a certain angle.

Turning is carried out with an abrasive material that has different grain sizes. Its choice is determined by the strength characteristics of the steel. Proper sharpening implies a certain order of work.

Sharpening angle

The effectiveness and quality of the event under consideration is limited by a fundamental parameter - the sharpening angle. Depending on their purpose, knives have the following meanings:

• Straight razors have the smallest angle – (7-11)°;
• fillet knives – (11-14)°;
• kitchen knives for most products, incl. bread, vegetables, meat, etc. – (16-21)°;
• hunting tools and knives for general technical purposes – (21-26)°;
• universal hunting knives – (21-40)°;
• a special tool that is used for cutting and chopping (for example, a machete) – (29-50)°.

The sharpening angle largely determines the thickness of the blade. At the smallest angles it should resemble a razor, and at large angles it becomes possible to manufacture especially strong, massive knives.

Important. Holding the abrasive element and the knife itself in your hands, it is very difficult to ensure a given angle along the entire length of the blade, which leads to uneven manual sharpening.

The main task of the device is rigid fixation one of the elements and a clear direction of movement of the second element.

Types and choice of abrasive

To sharpen knives you need abrasive stone which will ensure the necessary cutting of metal. The abrasive ability is provided by a certain surface grain size, i.e. the number of abrasive grains per unit area. According to this parameter, the following stones are distinguished:

• very coarse abrasives ( international classification– extra coarse) – have a grain size of less than 260;
• coarse abrasives – 310-360;
• medium abrasives – 390-510;
• fine abrasives – 590-720. This is the main category of sharpening stones used for cutting knives;
• very fine (ultra, extra fine) or grinding abrasives. They are used for sharpening razors and fine surface finishing of knife blades.

According to the nature of their origin, abrasive stones are divided into natural or natural(corundum, slates) and artificial (ceramics, artificial diamond). In addition, rubber elements are sometimes used for fine processing. When using abrasives, their surface moistened with water or soap-water solution(water instrument) and oil(oil stones).

The shape of abrasives can be round (discs) or rectangular (bars). The bars are most often used, and they are selected so that length significantly exceeded the length of the knife blade.

To fully sharpen the tool, it is recommended to have 2 bars of medium and fine grain. It is better to complement the set with a very small stone. The best option is to use double-sided bars, in which one side has a medium grain and the opposite has a fine grain.

Manual sharpening procedure

Any devices are designed to facilitate work and improve its quality, and the general procedure for manual sharpening remains the same:

1. The process begins with a coarse or medium-grained bar, which is laid on a plane. It is advisable to ensure its fixation.
2. The knife blade is brought to the abrasive surface at an angle equal to half the sharpening angle. The main task is to ensure a constant angle throughout the event.
3. With a smooth movement with light pressure, the blade moves from the beginning to the end of the block in the direction “away from you.” The edge of the bar must always be perpendicular to the direction of movement of the blade. Do not allow the blade to break off at the end of the stone.
4. After reaching the edge of the bar, movement is carried out in the opposite direction, while the sharp edge must always be on the surface of the abrasive. Changing direction is achieved by turning the handle.
5. The process is repeated until a burr along the entire length appears on the back of the blade tip. It should move to the opposite side when changing direction.
6. Next, take a medium-grained block, but with smaller grains. Sharpening continues, but the movements are carried out initially only “from oneself” until the metal shines on one side, and then the second side is also processed.
7. A fine-grained block is taken and the blade is processed until a mirror surface appears.
8. If a small burr remains, sharpening is completed by using a very fine grit sanding block. Some experienced people prefer to use instead of such a block leather belt. It polishes the knife blade perfectly.

Homemade devices

Home craftsmen make sharpening devices of various designs, but they all include 2 main elements - abrasive stone and knife fastening mechanism. A ready-made abrasive block is best suited for the device, but you can also make it yourself.

To do this, sandpaper of different grain sizes is glued to glass with a thickness of at least 4 mm. The connection can be ensured with double-sided tape.

Fixed device

One of the most simple devices done from 2 wooden blocks of triangular shape. They are fastened together with thumbscrews. An abrasive block is clamped between the wooden elements at the desired angle. This angle is set strictly according to the protractor.

When sharpening a knife on such a device, the blade must be constantly held strictly vertical. Naturally, ensuring such a direction is much easier than constantly guiding the knife at an angle.

Movable structure

To improve the quality of sharpening, it is necessary to fix not only the abrasive, but also the knife. You can also make such a device yourself. It is assembled on a flat, horizontal, massive surface. The device consists of 2 parts - rigidly fixed abrasive stone at the desired angle(similar to a fixed structure) and trolleys on wheels(on rollers) with a knife fixed horizontally.

The trolley moves manually along a guide rail. Provided by hand light pressure on the blade to the abrasive surface. This ensures desired angle sharpening and eliminates the need to provide the desired direction manually.

Direction changes can be made different ways. The simplest one is to make a cart with wheels at the top and bottom. When the bar ends, the cart simply turns over.

Dot machine

Sharpening machines have more complex design, which allows you to change the sharpening angle. Several options for a constructive solution can be given:

1. A knife is fixed on the platform with the possibility of adjustment. It is adjusted to the required angle and fixed permanently. The abrasive bar is mounted on a movable rod mounted on vertical support. It moves strictly horizontally. Sharpening is achieved by moving the abrasive relative to the knife blade.
2. It is fixed on a fixed frame, but the block can be moved along the guide to set the desired sharpening angle. The knife is installed in a movable table and secured magnetic holder, which makes it possible to turn it over.

DIY example

As an example, we can cite the technology of self-production of a sharpening accessory - an analogue Lansky sharpeners. It has a standard design.

The knife is fixed on a horizontal base, and its fastening is ensured by magnet. The sanding element is located on a rod along which it can move perpendicular to the knife. The guide rod is installed in the holes of the vertical post.

These holes are drilled at an angle to the surface of the post and thus set a certain angle for the rod. Several holes are drilled vertically in the rack and by rearranging the guide you can also change the sharpening angle.

Manufacturing adaptations are carried out in the following order:

1. On the base plate (, board, a metal sheet) on the edge slats are installed, limiting the displacement of the knife in the transverse direction. One of them is mounted in slots with thumbscrews for fixing knives with different blade widths. In the center of the knife location area is fixed magnet.
2. The emery block is secured on two pieces of corner, which are fastened with pins. Holes are drilled on both sides of this part for installation on the rod.
3. Steel rod with a diameter of 10-15 mm is passed through the indicated holes, and is installed at the end limiter to prevent the block from falling. The other end is cut thread.
4. On an aluminum U-shaped profile 30-50 mm wide, 5-6 holes are drilled with a diameter 1-2 mm larger than the diameter of the rod. The holes are drilled at an angle corresponding to the sharpening angles, taking into account the height of the location on the rack.
5. The rod is installed in the correct hole and fixed bolts.

This device works in the following way:

• the knife is fixed on the base and attracted by a magnet;
• a block of the required grain size is installed on the sharpening element;
• the rod is fixed in the desired hole on the stand;
• by hand, the block moves along the rod, processing the blade, and the movement is carried out “from oneself” and “towards oneself”;
• with the other hand, the knife gradually moves in the longitudinal direction.

See detailed drawings, descriptions and illustrations of a knife sharpener with and without a magnetic holder in the video below:

Scissor sharpener

With the help of knife tools you can also sharpen scissors, but such an undertaking has its own specifics. The sharpening angle is within (60-74)°. Tailor's scissors usually have an angle of (72-74)°. The cutting part at the point of contact of both parts is flat, and the bevel is made on one side. Main sharpening carried out from the outer, beveled side. Inner surface Only sanded with a fine stone.

The process is carried out in this order:

1. Disassembling scissors. To do this, you need to unscrew the screw holding the halves together and carefully separate them. A negative screwdriver is used.
2. Using coarse abrasive, it is carried out sharpening at the right angle. Movements are made only in one direction - “towards yourself”. Half of the scissors is held by the ring, and turning begins from the tip of the blade.
3. Using small block, is carried out fine-tuning.

Some scissors cannot be disassembled. They can also be sharpened, for which they open up as much as possible. The halves are sharpened one by one.

How to check the sharpness?

There are several popular methods for checking the quality of knife sharpening:

1. Paper. Take a sheet of paper (for example, for a printer) and cut off a strip at the edge. If the knife is well soaked, the strip is easily cut and has smooth edges. A dull knife crushes the edge and cuts unevenly, with tatters.
2. Tomato. A sharp knife cuts a tomato in half evenly, while a dull knife crushes it.
3. Hairs on the arm. A sharp blade works like a razor and cuts hairs, while a dull tool only crushes them.
4. Sharpness can be checked finger, remaining cautious. The presence of burrs indicates poor quality processing. Absolutely straight edges indicate high-quality work.

Knives tend to become dull, making them difficult to use. Sharpening devices and machines will help solve the problem by ensuring the correct sharpening of the blade, restoring the specified angle. There are many designs of simple knife blades, and the owner must decide which one to choose.

Knife sharpening device - necessary thing in every house. Of course, you can purchase an industrial-made sharpening machine. But you should keep in mind: the scissors that are sold in specialized stores are quite expensive and often fail.

Construct a simple sharpening machine you can do it yourself. This sharpener does not take up much space and is very easy to use. If you don’t want to make something, you can use a regular sharpening stone. However, a knife sharpening machine is still a great idea, because the simplest machine It will always come in handy, and you can sharpen other tools on it.

Why do knives get dull?

In some houses there are knives They remain sharp for a long time and there is no need for sharpening. And for some owners, on the contrary, they become stupid every now and then. Why is this happening? Here are the most common reasons:

DIY machine

Once upon a time, sharpening machines were rare. When a sharpener came to a village or town, all the local residents brought him their knives, scissors and other cutting tools. In those days, the machine was a circle on which horizontal plane a knife was placed. The circle rotated and the blade became sharper.

Until now, many owners who take care of their knives sharpen these objects in a horizontal position, using a special whetstone. It is made of an abrasive material, and the blade, in contact with the bar, restores its sharpness. If you don't have a sharpening machine, this method can be used. However, sharpening knives in a horizontal position is very inconvenient, especially if you do it while hanging. In this regard, many home craftsmen make their own sharpening machines. Here are the main advantages of such a machine:

Operating principle of the device

Here's how a simple sharpening machine works:

To sharpen on such a machine, you do not need to apply any physical effort, and good result achieved very quickly. The risk of injuring your hand is reduced to zero.

Once the blades are sharpened, the question arises of how to properly use and store them. Many housewives, after washing their knives, do not wipe them dry with a towel, but simply put them in a pile in the dish drainer so that the water drains from the cutting tools. Under no circumstances should you do this. When undried, wet knives lie on top of each other in a horizontal position, they quickly rust and become dull.

Therefore, together with a sharpening machine, it makes sense to design a special device for storing knives. Such a device is wooden stand, in which slots of various sizes are made. Blades are inserted into these slots with the blade facing down. This way, the cutting tools do not come into contact with each other and the blades are always dry. In order to remove the knife from the “socket”, you just need to gently pull its handle.

Correct use of knives

Of course, sharpening knives on a homemade machine is a pleasure. It's nice to watch how a dull blade becomes sharp and begins to shine. However, no one likes to do extra work. Therefore, in order to sharpen them less often, you need to properly care for them. Here are some useful tips:

The sharpness of kitchen appliances largely depends not only on the quality of the product and the metal from which the blades are made, but also on storage conditions. Even the most good knife It will quickly rust if you constantly keep it in water and store it horizontally with other kitchen utensils.

Proper sharpening of knives is of great importance not in everyday life. When the blade is well sharpened, working with it is easy and pleasant. But the main thing is that it is much more difficult to get injured with a sharp knife than with a dull one. Sharpening knives on a homemade machine will not take much time and effort, but after that the cutting tools will become as good as new. Sometimes homemade sharpening machines are even used in cafes and restaurants to make the work of chefs easier. But you can also use an ordinary block, because it all depends on your desire and capabilities.

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 to modern man do not resort to the work of specialists, but do all the work yourself at home. To sharpen knives you can use: special device industrial production, and any device manufactured with my own hands. It's important to know that simple elements for sharpening knives (for example, a whetstone), which 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 homemade device for sharpening knives can be based on the use of these simple sharpening devices. Details on how to make your own sharpener can be found below.

A homemade manual machine for sharpening knives, provided that all the requirements for its creation are met, will simplify the sharpening of knives and its performance will be no worse than that of a professional. Proper sharpening includes next 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). Sharpening device, 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

When sharpening the edges should be processed evenly. To fulfill this condition, the following rules must be observed:

• the blade must be fixed in the vice of the device reliably and efficiently, without exposing the metal of the blade to damage;
• the movement of the whetstone 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 sharpening device;
• the pressure on the knife blade should change smoothly depending on the change in the area of ​​contact between the blade and the sharpener.

A simple device for sharpening knives

The simplest device for sharpening knives is based on the use of an angular frame and a whetstone. The price of such a primitive factory-made device is quite high, as is the price of replaceable whetstones, but making such a device for sharpening knives at home will not be difficult for a craftsman. You will need the following equipment:

1. Wooden blocks of the same size - 4 pcs.
2. Drill (or any other drilling tool).
3. Bolts and nuts (about 4 pieces each).
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 together parallel to each other as a single whole and drill holes through the diameter of the bolts. Insert bolts into the holes and tighten the corners slightly with nuts.

The point of this invention is that it is possible 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 properly secure the whetstone between the wooden corners of the device. 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 modification of the device, you can also fix the position of the knife relative to the sharpening stone. A significant disadvantage of such a machine for manual sharpening is the inability to smoothly adjust the angle of inclination of the sharpening stone.

Device for sharpening from mounting angles

The diagram and drawings of a homemade knife sharpener made from mounting angles, based on a Lansky device, 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 M6 thread and length 160 mm.
3. Thin rod (electrode, knitting needle, etc.).
4. Touchstone.
5. 2 rectangular pieces of metal (sponges for clamping the whetstone).
6. Pliers.
7. Hacksaw for metal.
8. File (or any other tool for processing sharp corners).
9. Set of hardware (nuts and bolts).

In both metal jaws, intended for fixing the keystone, you need to drill for a connecting bolt. Fix the touchstone. A thin smooth knitting needle, previously bent at an angle of 90º, must be inserted and secured in the hole of one of the jaws. In the future, using this knitting needle-shaped clamp, a certain angle of inclination of the touchstone will be set. Such a device for sharpening knives is characterized by a wide range of sharpening angles, which will undoubtedly be of interest to most craftsmen.

Locking blade machines

Knife sharpening machines with locking blades will attract the attention of those people who want to sharpen a knife not only efficiently, but also quickly. A design that rigidly fixes the knife blade relative to the moving one. set angle sharpening stone, 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 440*92 mm and a thickness of 18 mm.
2. Wooden die 92*45*45 mm (for fixing the vertical threaded rod).
3. A wooden block 245*92 mm and 18 mm thick (the plate to which the knife will be attached).
4. Iron plate 200*65 mm and metal thickness 4 mm.
5. Piano hinge, 92 mm long.
6. M8 hairpin 325 mm long.
7. Nuts and bolts with M8 thread.
8. Drill 6.5 mm.
9. M8 tap.
10. Self-tapping screws 50 mm, 4 pcs.

The die intended for fixing the vertical threaded rod 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 die, approximately in the center.

Next, in the resulting hole you need to cut a thread for an M8 stud. The wooden block 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 holding device, you can begin to attach the iron plate. In the center of the 200*65 mm plate, you need to drill an oblong groove, 90 mm long and about 1 cm wide. The groove should be located from the edge of the clamping plate at a distance of 60 mm. Additionally, you need 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, you need 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 device is preparing the control device that will set the sharpening angle of the knife. For this you will need:

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

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

Connect the touchstone to a guide rod, which is a steel rod with a cross-section of 8 mm. When connecting the keystone and the guide rod, you should strictly ensure that their center lines coincide. If desired, for ease of use of the sharpener, a handle-holder can be attached to the whetstone on the reverse side. All that remains is to secure the whetstone in the guide mechanism, secure it with a thumb and the homemade device for sharpening knives is ready.

Machines with fixed sharpening surfaces

Machines with fixed sharpened surfaces are a simple modification of the device for processing household knives. In such a device there is no possibility of adjusting the sharpening angle; however, several can be set in advance different angles for sharpening different types knives. The work of sharpening blades using such machines is not difficult; you just need to move 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 equip almost any device for sharpening knives and scissors with an electric drive. Like sharpening machine allows you to quickly and efficiently sharpen the product and at the same time provides a better concave shelf at the edge of the blade.

The mechanism of an electric sharpener for sharpening knives contains a guide, which is located along the axis of rotation of the sharpening stone, 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 tempering of the hardened steel, as a result of which the knife can quickly lose its hardness and its service life will be noticeably reduced. To prevent tempering of the steel, sharpening should be done on a high-speed electric sharpener in short periods of time and with sufficient breaks to allow the knife to cool.

Making sharpening stones

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

• a wooden die to the size of the future sharpener;
• epoxy resin;
• cardboard boxes according to the size of the block;
• abrasive;
• protective rubber gloves.

You can use ready-made powder as an abrasive, or you can prepare an abrasive own production, for example, from an old block Green colour still of Soviet production. Such a block can be ground into powder and used in the future as an abrasive.

The wooden die needs to be treated on one side with sandpaper and frequent cuts must be made with a saw. Mix epoxy resin with abrasive chips. Having previously placed the block in a cardboard box glued to the size of the block, cover the prepared surface wooden block mixture epoxy resin and abrasive. Once the resin has completely cured, the block is ready for use.

Another option for making your own sharpening stones is to create a sharpening stone 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 sharpening stone is ready for use.

Device for sharpening from wooden blocks

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

Wooden slats should be thoroughly sanded with abrasive sandpaper. Then, after applying auxiliary markings, depending on the sharpening angle of the knife, make cuts to a depth of 15 mm. Insert sanding blocks into the resulting holes so that each groove matches, then secure them with bolts. To give the sharpening device greater stability, the lower part of the surface can be padded with a piece of rubber.

Types of sharpening devices cutting tool are different and each master will be able to choose the one manual machine, which will fully satisfy his needs.

Interest in making knife sharpeners with your own hands arises for a reason. Consumer qualities hand cutting tools are increased through the use of modern materials and technologies for blade manufacturing and precision factory sharpening. At the same time, the price of the product increases, but it is becoming increasingly easier to ruin a fairly expensive item with primitive sharpening. Therefore, various household devices for sharpening knives are no longer needed only for convenience. To understand why a knife sharpener is still needed and how to make it correctly, you will have to start with the ideology and evolution of the knife.

Why do you need a sharpener?

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

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

They sharpen a knife by beating it in much the same way as beating a scythe, only the whetstone is motionless and the blade is moved. First, they pull it along the whetstone with the butt away from you, then they turn it over and pull it with the butt towards you. The position of the cutting edge (CR) on the whetstone is always dragging; quick movements: shirk-shirk! During 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 to sharpen a knife by beating is not very difficult, and with some skill you can create a smoothly running profile on the blade, see below. However, the Finnish knife is, in general, a dead end in the evolution of a cutting tool, surviving in special natural conditions.

A good knife has never been cheap, and in extreme situations, the durability of the blade, combined with the toughness of the blade, became vital factors. Therefore, even in ancient times, they learned to harden knife blades from the surface and cement them: the core remained viscous, not brittle, and a hard, red-hot crust formed on the outside, see next. rice.:

It is still possible to sharpen a knife with a cemented blade, but you need a skill that is not given to everyone. And the abrasive is already needed from a special type of stone - lithographic grunstein slate. There is little of it in nature; Grünstein is still considered a strategic raw material. There is no artificial grenstein and it is not expected. It’s as easy as shelling pears to ruin a cemented knife with inept beating - a little somewhere the cementation bark will be stripped down to raw metal (this is not visible to the eye), the knife will only have to be thrown away, the blade will immediately become dull and begin to crumble.

Note: if you have an old whetstone for a scythe lying around somewhere greenish color, don't throw it away, it's a valuable rarity.

Service knives do not require the same durability and toughness as hunting and hiking knives, and they should cost much less. As a result, special steels and powder metallurgy are widely used in the production of utility knives. The blade of an “eternal” kitchen knife is structured like a rodent’s incisor: in longitudinal layers, the hardness of which decreases from the core outward. In any case, you have to sharpen the knife less often, but chipping is definitely ruled out - the blade immediately becomes discolored.

How to sharpen a knife?

For these reasons, push-pull sharpening technology (push-pull sharpening or push-pull sharpening technique) was invented long ago:

1. The blade is pushed along the touchstone away from you with a twist, holding the butt towards you, the position of the RK is advancing (scraping);
2. Then, without lifting the blade from the whetstone, they pull it with the butt towards you, turning it reverse side, the position of the Republic of Kazakhstan is dragging;
3. The blade is turned over and repeat steps. 1 and 2;
4. pp. 1-3 are repeated, reducing the pressure in each cycle, until the burr formed on the RA disappears (does not stick together).

Note: when they say or write “the hangnail will go away,” etc., this is incorrect. Metalheads have a slang word for it: "zausavka"; for electricians - “switch off”. But in Russian, a burr and a switch are masculine.

Push-pull sharpening protects 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 whetstone, smoothly changing it in accordance with the curvature of the wheel.
• Make sure that the tangent to the generatrix of the blade and the transverse axis of the contact spot of the wheel with the touchstone coincide.
• Also ensure 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 meet all these conditions at the same time, completely symmetrically on the forward and reverse stroke of the blade along the touchstone, and modern knife, as stated above, it can be damaged by improper sharpening. Any household device for sharpening knives is designed to relieve the sharpener from continuous monitoring 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 times the length of the knife blade from the handle to the 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 process. Sharpening with a simple blunt wedge (item 1 in the figure) gives a stable but rough blade: the cutting resistance is high, and the knife tears quite viscous materials. A sharp wedge (item 2) quickly dulls or chips; on viscous and/or fibrous materials, the cutting resistance may be greater than with a blunt wedge due to the friction of what is being cut against the blade.

Ideal in all respects is the ogival (smoothly sloping) profile, pos. 3. Experts are still arguing which generator is better - an involute, a hyperbola or an exponential. But one thing is certain - making an ogival blade in production conditions is difficult and expensive, and it is impossible to direct it yourself. Therefore, ogival sharpened knives are used only in special equipment, e.g. microtomes - biological devices for obtaining the thinnest tissue sections.

For disposable blades, e.g. safety razor blades, faceted sharpening is used, pos. 4, i.e. The ogive generatrix, as mathematicians say, is approximated by straight segments. The number of sharpening edges is indicated in the certificate or on the manufacturer’s website. For thick, rough stubble would be better suited 3-4-sided; for delicate hair not on the face - 8-sided. The 6-sided one is considered universal.

Angle α

The sharpening angle is always given in half the value α, because Many tools and, for example, bayonet knives are sharpened on one side. For knives for various purposes, the angle α is maintained as follows. within:

• 10-15 degrees – medical scalpels, straight razors, knives for artistic carving.
• 15-20 degrees – pastry knives (for cakes) and vegetable knives.
• 20-25 degrees – bread and fillet knives.
• 25-30 degrees – hunting, hiking, 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 manufacturing process of the blade and cannot be sharpened. In fact, sharpening a knife with one and a half sharpening is no more difficult than sharpening it with a simple wedge. One-and-a-half sharpening is optimal for a knife that works with a variety of materials, and making a knife sharpener with one-and-a-half sharpening is much easier than using a faceted sharpening.

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

1. Hunting and camping knives are not supplied. This makes it easier for them to cut hard things (for example, bones) with broaching (with filing). In addition, if you accidentally cut yourself, the slightly lacerated wound stops bleeding faster, heals more easily, and there is less danger of infection getting into it.
2. After abrading, the blades of straight razors, shoemaker's knives and for artistic carving are brought to 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

Homemade sharpener for knives it will be much more convenient and accurate if you do not buy a whetstone for it, but make it from a piece of square corrugated pipe 200-300 mm long (on the left in the figure below) or a wooden block.

The edges of the base are covered with sandpaper, respectively. numbers. Glue – stationery adhesive stick. The advantages of a skin-based donkey are obvious:

• Much cheaper than an emery block.
• Can be made with 4 numbers of abrasive, while sanding blocks have a maximum of 2 sides.
• Wear (depletion) of the abrasive is possible no more than the thickness of the abrasive layer of the sandpaper; the waviness of the RK due to the rotation of the whetstone on the sharpener rod (see below) is also no more than this amount.
• As a result, the sharpening angle error due to the development and rotation of the whetstone does not exceed fractions of a degree.
• The chip from the pipe can be put on a threaded rod (in the center in the figure), which makes changing the abrasive faster and easier.
• A touchstone made from a pipe or a wooden block is held in any clamps under an emery block no worse than the last one, on the right in Fig.

Knife sharpening devices

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

The use of a simple knife sharpener can be further simplified to the point where no skill is required if you supplement it with a sliding shoe with a magnetic knife holder, pos. 2. The sharpening order in this case is as follows:

1. Knife right hand hold by the handle, turning in the direction of movement according to the curvature of the blade;
2. With the fingers of the left hand, except the thumb, press the shoe to the whetstone;
3. With the thumb of the left hand, they press on the butt of the blade, pressing the RK to the abrasive.

The function of maintaining the angle of inclination is removed from the operator, and the rest are distributed between 2 hands. In this case, the skill of sharpening with your own hands is developed immediately, but you need a holder that firmly holds the knife and at the same time allows it to slide over its surface. You can make one from the magnets of the write-read head carriage drive 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 position 3). They are glued with DIFFERENT poles onto 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 wear out immediately.

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

L.M.

The use of a manual knife sharpener such as Lansky-Metabo, pos. 1 in Fig. The diagram of its device is given in pos. 2, and the procedure for use is in 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 touchstone 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. The angle also “floats”. Therefore, the Lansky-Metabo sharpener is used primarily for sharpening camping and hunting knives with a relatively short blade.

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

Towards the middle of 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 tip the B angle will increase again, making the tip more resistant to drilling, chiselling/impacting and punching (piercing).

Note: Another disadvantage of the Lansky-Metabo sharpener is the difficulty of performing desktop version. But this drawback, as they say, is fake, see pos. 5.

Drawings of parts of the original Lansky-Metabo sharpener are given in Fig. The numbers at the windows under the rod (guide) correspond to FULL sharpening angles.

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

Note: on the trail. rice. An assembly drawing of the Serjant sharpener is given. Regarding the inconvenience of fastening in a vice, see above.

Knife sharpening machine

The most advanced household manual sharpener today is a knife sharpening machine Apex type. His appearance, device diagrams and instructions for use, see Fig. Apex can be made with a continuously variable sharpening angle (item 2) or with fixed angles like Lansky-Metabo (item 3). Normally on Apex they work like on Lansky-Metabo (item 4), but for more precise sharpening other options are possible, see below.

Homemade version of the Apex sharpener - Skomorokh knife sharpener

In 2016, the desktop modification of Apex by Ivan Skomorokhov made a splash in the RuNet, perhaps no less than the bubafon stove once did, see fig. on right.

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

How to make a knife sharpener Skomorokh, see video:

Not just knives...

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

There are special devices for sharpening carpentry tools, which require a special discussion. Homemade products like a roller sharpener-trolley, see fig. on the right, they are more of a curiosity: not to mention the complexity, they require a stone or steel table, and, most importantly, they do not guarantee against distortion 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, a modification of the Apex for sharpening was flashed, not inferior to that of a factory electric semi-automatic sharpening machine. The alteration is not difficult, see figure: the rod is set horizontally according to the level and the rod level is held along the same level while 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 offset of the contact point is from 250 mm, it is possible to sharpen chisels and planer pieces up to 120 mm wide.

In this operating mode, a zero (theoretically) sharpening angle error can be achieved by keeping the bar stationary and moving the knife held by the magnetic holder, see above. In this way, it is also possible to sharpen the pieces of shaped planes if a round, semicircular, elliptical or segmented whetstone is placed in the clamps. The main thing is that the touch spot is always point-like.

...but also scissors

Another modification of the Apex sharpener for sharpening scissors (also a necessary thing in the household) is shown in Fig. on right. The total work required is a couple of pieces of angle or galvanized scraps and 4 additional holes in the sharpener table. For the process of making your own attachment for sharpening scissors for the Skomorokh sharpener, see next. video:

Video: sharpening scissors, attachment to the sharpener Skomorokh

Finally, about scissors

Before you grab your poorly-cut scissors and stick them in the sharpener, check to see if the hinge is loose. Open the scissors and look at them from the side. Do you see how the tip is turned with a screw towards each other? That’s why scissors cut: the point of contact of the blades when cutting moves from the roots to the ends. And therefore it is difficult to cut with scissors with your left hand: turning the ends is designed for the kinematics of your right hand. And if the hinge of the scissors is loose, the blades will move away from each other and will not even be able to cope with paper. In this case, you just need to tighten the riveted joint with a hammer and the screw joint with a screwdriver.