Everyone knows that working with a dull knife is not only difficult, but also dangerous. Due to the slowdown in the work process, tension in the muscles increases and the blade, just like that, will come off, causing serious injury. Alternatively, you can use the services of a workshop, but this will take certain time, which is often in short supply and will require financial costs. But if you have a knife sharpening machine at home, the process will speed up significantly.
Why do knives lose their sharpness?
Cutting products, no matter what their quality, become dull over time. This occurs due to the blades changing shape as a result of the loss of microscopic particles of the material from which the blade is made when interacting with the object being cut. In addition, under pressure, which is sometimes quite strong, the cutting edge is deformed as a result of deflection in any direction.
In addition, the cutting direction is not always maintained, which causes curvature of the very edge of the knife surface and makes it difficult to pass along the cut line. This is especially evident in blades made from low-grade raw materials.
Many people think that in hot water knives get dull much faster. This assumption is partly correct, although it is not decisive. Such tap liquid is saturated with salts and metals much more strongly than cold liquid, therefore their interaction with the cutting surface has a negative, although not decisive, effect.
How to sharpen a blade
Household cutting accessories are made from special and powder grades of steel. The structure of their sharpening resembles the teeth of rodents: the further from the edge, the less hardness of the cutting layer.
Therefore, ideal manual sharpening of knives occurs according to the push-pull principle or the push-pull method (from English push-pull sharpening):
- The cutting blade is first pushed away from itself with a scraping motion, with a slight turn to the side.
- Further, without lifting the blade from the sharpener, the movement occurs towards itself, with a turn in the opposite direction.
- This continues until sharpening is complete, with a gradual weakening of the pressure.
This technique requires certain skills from the sharpener, as well as careful attitude to the blade itself. At in a similar way required:
- Clearly maintain the tilt of the knife, gradually changing it depending on the curvature of the knife.
- The contact spot of the blade must coincide with the tangent line of the whetstone and be perpendicular to its longitudinal axis.
- The pressure on the surface must be changed smoothly.
It is difficult to carry out the process, observing all the rules when moving the blade in both directions, and an incorrect result renders the blade unusable. To relieve the sharpener from constantly monitoring the sharpening process, they came up with machines for sharpening knives.
Necessary conditions for sharpening
Maintaining the angle between the edges of the blade when sharpening it is the key to effective use and long service life of household accessories. It must be restored in accordance with technological standards, then there will be no problems with cutting. For knives for various purposes there is a sharpening angle:
It is difficult to maintain the required parameters without using a special device. Therefore, there are many ways to make them yourself. It’s easy to do, and you won’t have to spend much time at all.
Sharpener parts
No matter how many such devices are invented, common features they have the same ones. The main and constant parts of any sharpening tool are;
- Abrasive component.
- The thrust part.
All sharpening components that are used at home and at work are presented in stores. Here are the main ones:
- Ceramic bars.
- Natural stone.
- Diamond sharpener.
- Japanese water devices.
The most popular and affordable abrasive is a ceramic stone, which is most common in retail outlets. Most often this is an ordinary boat for rough sharpening the blade. There are double-sided bars, which are preferable for household use. This is an inexpensive device, the replacement of which as it wears out will not bring large financial costs.
Grinding using diamond stones is more complex and expensive. Besides high price, such sharpeners quickly wear out the working part of the blade.
The best whetstones for sharpening are natural and Japanese stones. However, their price is very high and they are not produced in our country.
Homemade sharpening device
In order to make a knife sharpening machine with your own hands, the first thing you need to do is find a suitable drawing. There are many modifications for its production.
The easiest way
This option does not require special skill or the use of expensive components. To make it you will need:
- Wooden corners with a side of 20-30 centimeters: 2 pieces.
- Screws with nuts in the amount of 10 pieces.
- Protractor for precise angle setting.
- In addition, you will need a drill and drill bits.
To make it, you need to mark the corners and drill 3-4 holes at identical points. Place a block between them at the desired angle and secure with bolts.
To sharpen a knife or scissors, you simply need to run the blade along the surface of the block, holding it strictly vertically.
To change the sharpening angle, you simply need to loosen the fasteners and modify the position of the abrasive part. In order not to pick up a protractor every time, it is recommended to put marks on the base, marking the main positions of the block.
The ability to change the sharpening angle is the only advantage of this manual machine For . In terms of convenience, it is not far from an ordinary bar.
Sharpening machine is more complicated
For more comfortable work, a more complex device will be required. . To make it, you need the following parts and tools:
- Plywood, laminate or chipboard.
- A meter strip with a thickness and height of 2-4 centimeters. You can take two pieces, one longer, the other shorter.
- Bolts with nuts - 2 pieces.
- Hacksaw and marking tool.
First you need to make a knife holder. To do this, from a piece of plywood, or whatever is available, you need to cut a rectangle measuring 10 by 4 centimeters (dimensions are approximate). The wide part must be ground at an acute angle to prevent the block from touching its edge when sharpening.
For the base, you need to cut out another piece of plywood with dimensions of 30 by 25 centimeters.
At a distance of 1-2 centimeters from its edge, a holder is placed with the cut outward and secured with bolts. The blade will be located between them.
The next stage is the manufacture of a stand from a long rail, along which the bar moves at a fixed angle. It needs to be installed vertically on the base and the angle measured in relation to the holder. The upper part is cut at the appropriate angle. The second post is cut in a similar way and connected with the rest of the rail on top, so that the result is a U-shaped part.
The assembled structure is attached to the base on the side opposite to the holder. This can be done using screws or wood glue.
All that remains is to make the base for the abrasive part. To do this, stick sandpaper with a grit from P600 to P2000 onto a short strip.
To work with such a sharpener, it is better to place it on the edge of the table in such a way that the protruding bolts connecting the base and the blade holder rest against it, thus preventing the device from sliding.
Electrical devices
These are the most versatile devices. When using them, the sharpening angle is selected independently; just select the desired position of the blade. Main part electric machine for sharpening knives - sanding wheels with different grain sizes and slopes. The discs are driven by an electric motor. Therefore, energy dependence is a disadvantage, although not the main one in the use of such equipment.
The main disadvantage of this method of sharpening is the inability to visually control the process, since to ensure safety during sharpening, all rotating mechanisms are completely closed.
It is impossible to make such a device at home. Therefore, it is simpler: a disk or belt abrasive is attached to a conventional electric motor. When using a round stone, a stop is installed with the ability to change the inclination of the blade. Any cutting tools can be restored on such a machine.
Errors during manual work
Not every family has professional specialists to do this kind of work. In order to properly sharpen a blade, you need to avoid typical mistakes that beginners do:
Brief overview of models
Except homemade devices for sharpening, there are many similar devices available in the factory. The most popular of them are:
These are the most well-known brand names, and cheaper and simpler devices can be purchased for 20-30 dollars.
Much more convenient, but also more expensive electrical installations. Small Chief’s Choice devices of various modifications cost from 120 to 250-300 dollars. Their sharpening angle is fixed, 20 degrees, and is used for sharpening flat knives in cafes and restaurants.
The same company offers a large number of mechanical devices, which are an abrasive bar in a housing installed at a certain angle. For them you will have to pay from 40 to 50 dollars.
Any cutting tool tends to lose its sharpness. It depends on the quality (or properties) of the material, conditions of use, and the type of object being processed (the one you are cutting). The knife is no exception. In addition, the sharpening method affects the rate of dulling.
The dependence is inverse. Sharp corners improve cutting ability, but contribute to rapid loss of properties. Conversely, obtuse angles retain their original state longer, but the quality of the cut is much worse.
When making a blade, the craftsman gives it a basic shape, implying a certain edge format.
To be fair, we note that the method of sharpening also depends on the use of the tool. There are ones designed for thin cuts, and there are ones for crushing bones.
There are machetes designed for cutting branches. Therefore, when choosing the shape of the future cutting edge, all these factors should be taken into account.
Various knife sharpening machines, from home tools to professional equipment, are designed to restore the sharpness of the blade. But before you sharpen your knife, you need to decide on the sharpening angle and what you will sharpen it with.
How to sharpen knives?
Since ancient times, blades were sharpened exclusively with stones. Moreover, no one made them industrially; they simply found a suitable surface on the banks of reservoirs or on mountain slopes. Stones for sharpening knives are still used today. In addition to natural ones, industrially produced ones are used.
One of the most common natural sharpening stones. This device is also called Japanese stone, since mining is carried out mainly in the land of the rising sun. Today, artificial analogues are produced, but among connoisseurs of high-quality blades, natural material is valued. 
If you, after reading this information, run to the store, you will most likely have to return with nothing. A real Nakayama MARUKA, or Namito Aisa, not only has a price tag of about $1000. It's not that easy to find. This is a piece product, each bar is unique (in terms of shape and size). 
Therefore, most lovers of polishing their knives (mainly Japanese) prefer inexpensive, but fairly high-quality artificial “water stones”. 
Some experts believe that pressed abrasive can be brought to a grain size that is unattainable for natural materials. This is true, so buying a “real” stone is nothing more than a tribute to samurai traditions. Artificial emery is more practical and has correct form, and most importantly - a relatively affordable price.
Modern housewives use a large variety of knives for cooking. A tabletop utensil with the right sharpening angle will help you keep your kitchen knives in order. Special sharpening of the blade is used for hunting and tourist knives. A properly sharpened blade can save the lives of hunters, and serve as a tool for tourists to prepare wood chips for a fire. There are many different types of knives used by humans, and there should be a perfect sharpener for each one. In everyday life, everyone can have a tabletop machine for sharpening knives with their own hands, which will help housewives, without waiting for help from the stronger half of humanity, to sharpen the blades of working tools on their own.
Small sharpeners for kitchen knives
A tabletop machine must have several blade sharpening angles. This simple device won't take up much space. Meat knives and vegetable peeling knives have double-sided blade sharpening with the same angle. The fish knife-saw has a single-sided blade. The bread serrator can have single-sided or double-sided sharpening. And each knife is given a certain sharpening angle provided by the manufacturer. The degree of inclination of the knife is set by adjusting the bar. Changing the angle will lead to a dull blade, making the knife unsuitable for safe work.
Most manufacturers of miniature machines use a "universal angle" of double-sided sharpening of the blade. This device can be used to sharpen flat knives. The sharpener with a vacuum suction cup is easy to install on a smooth table surface. It is almost impossible to sharpen blades made of very thin steel without serrations, since it is designed for medium-thick steel knives. This device is not intended for serrated knives. His emery has a strictly defined trajectory.
Long but high-quality blade editing
A professional sharpener will be much better in this case. True, the cost is quite high. Its working part is the same block that is used for manual sharpening. Its peculiarity is that professional sharpener allows you to install and secure the knife blade at a certain angle relative to the moving block. The process will take a little longer, but there will be no jagged marks on a steel blade of any thickness, and the knife will last longer. True, the professional universal sharpener does not have such attractiveness - it does not have a plastic case.
It is more advisable to use a knife sharpening set with adjustable clamp angle, despite its high cost. The set includes a tabletop mount. When purchasing such a set, it is more profitable to allocate a special place for its permanent installation in order to secure the case. The set includes 5-6 bars with different degrees of grain. Sharpening is carried out in several stages, starting with a whetstone that has a smaller grain size. It is not recommended to press the block too hard, as it is not very thick. It is better to make more passes of the block along the blade.
In some sets, in addition to sandpaper, there is a block covered with leather. It is intended to give the blades a natural metallic shine using special pastes, for example, “Goya”. You can also find a jar of oil in most sets. A drop of this substance helps to clear the block of metal chips stuck in it during operation. It is worth noting that full-fledged professional sharpening of 1 knife on a manual machine can take up to 2 hours.
Electric sharpener
An electric knife sharpening machine gives more quick results. Its design is quite simple - the working part is diamond-coated emery; an abrasive disc is used for rough sharpening. Using magnets that serve as guides, the sharpening angle of the blade is set. As a rule, most electric household sharpeners have one sharpening angle of 20, 30 or 40 degrees. Some have replaceable blocks in which the sandpaper has different angle sharpening. It should be noted that such a device is also not capable of sharpening a wavy blade. Serraters cannot be sharpened on such a machine.
The design of most mechanical and electric sharpeners for knives is designed for sharpening flat knives that do not have a wavy blade. By correctly positioning the knife between the guides, you will get a sharpened blade, but at the angle specified by the manufacturer. The quality of sharpening is affected by the grain size of the emery used in a particular model; as a rule, this indicator is indicated in the product labeling. Unlike sets, processing is carried out with one type of abrasive rotating disk. In rare cases, a device is provided for 2-phase processing of the blade.
The mechanical device, as well as the electric sharpener, can be assembled independently. Each device is equipped with a sharpening stone. A manual machine requires bars, and an electric sharpener, the design of which is determined by the motor used to set the movement, requires a stone shaped like a circle. Most often, when designing homemade machine for sharpening knives, motors from washing machines activator type, setting rotational movement.
A desktop homemade machine consists of a motor, a rotating sandpaper and a movable adjustment table. A properly installed table will make the sharpening process safe and accurate.
The engine is mounted on a metal frame, which in turn is fixed on the table. A bushing is attached to the engine, and a grinding stone disc is secured to it. On the side of the person working on this machine, a device is installed to adjust the inclination of the blade in relation to the stone. This device is no worse than guide magnets, but the main thing is that the hand does not tremble, otherwise you can get hurt on the sandpaper if another device is not used as a stop - a stop. For sharpening hunting knives with thick steel, perhaps this is the only correctly selected device.
The emery of the whetstone consists of silicon carbide and corundum. Finer emery is made from corundum and chromium oxide. The stone itself must be very durable. For a long time, silicon rocks have been classified as such rocks. Silicon dioxide stones can be found on sale. These stones are cheaper because they are not as rare as Arkansas stones. Arkansas stone is a fine-grained homogeneous rock of crystalline silica - quartz. A properly selected sharpening stone will not become clogged with metal chips. The sandpaper will last longer.
A device for sharpening knives with your own hands is required device for any work in the kitchen or workshop. Usage is perfect sharp knives makes cooking much easier, allowing you to use less force to cut meat, slice vegetables or bread. Working with a dull knife is not only inconvenient, but also dangerous, because such a tool can fall off the material being cut at any moment and cause injury to you.
Using a homemade knife sharpener, you can sharpen a knife at any angle, since the sharpening angle is independently adjustable.
In order to bring any knife to a sharp state, you should know optimal angle his sharpening. This parameter depends on the grade of steel and the purpose of the knife. Homemade devices will help you set the knife at the right angle to sharpen it quickly and efficiently.
How to sharpen knives correctly
Figure 1. Device for sharpening knives “Domik”.
Some types kitchen knives impossible to sharpen yourself. These include specially shaped tools (for example, a bread knife or other types of knives with a raised edge). You should also not sharpen ceramic knives. However, the advantage of the listed tools is that manufacturers try to make them from especially hard grades of steel, so they do not become dull for a long time.
For correct sharpening You should choose good abrasives of different grain sizes. Store-bought versions of such bars are quite expensive, but you can always make a block yourself from a piece of wood covered with fine sandpaper. It is important to have devices of different grain sizes: large ones for preliminary “grinding”, and small ones for grinding.
The optimal sharpening angle for a knife edge is from 20 to 30 degrees, depending on the functional purpose of the tool. It is quite difficult to sharpen manually at this angle, so simple homemade mechanisms are used for this purpose.
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Assembling a knife sharpening device
Among the many tools for sharpening knives with your own hands, you should choose the one that will best suit your goals. All devices have a fairly simple structure and consist of two main parts:
- stop for securely fastening the knife;
- a movable block of abrasive material.
Figure 2. Wooden body in the form right triangle to place the whetstone.
The simplest tool for creating a sharp edge on a blade is called a “house” (Fig. 1). It looks like a rectangular or wooden block square shape, the upper edge of which is processed in the form of a gable “roof”. The angle of inclination of the edges of such a block is 20-25°. The knife to be sharpened is placed with its edge close to the ridge of the “roof”. By moving the abrasive bar in a horizontal plane along the blade, we will ensure that the sharpening angle remains constant.
There are also quite complex devices. To create them you will need some materials, tools and a little time, but you will ensure yourself for a long time convenient tool for sharpening. The device is assembled from the following materials:
- wooden board, dimensions 500x150x20 mm;
- metal studs, 8 mm in diameter with thread;
- several M8 bolts and nuts, wood screws;
- wing-type clamping screws;
- textolite or piece of steel for the pressure plate;
- optional neodymium magnet for securely holding the knife during the sharpening process.
From wooden board you need to make the body in the form of a right triangle, and the lower leg should be slightly longer, since a stand for the grindstone will be placed on it (Fig. 2). The inclined board is attached at an angle of 20° to the base. A hole is made in it for attaching the pressure plate, through which a screw with a wing nut will pass.
Figure 3. It is necessary to drill a hole for a vertical pin, which will serve as a holder for the abrasive device.
Near acute angle structure, you need to drill a hole for a vertical pin, which will serve as a holder for a movable abrasive structure (Fig. 3). A small one is put on the hairpin wooden block, which is clamped with a screw and a clamping nut.
The last element of the device is another pin with a clamp holder for an abrasive bar (Fig. 4). Clamps can be made independently from wood, metal, ebonite or other material, or you can use a disassembled clamp for this. For better stability, you can glue rubber feet to the bottom of the instrument (video 1).
In order to sharpen a knife using such a device, it is placed on a magnet, and if there is no magnet, it is pressed against the stop, holding it with your hand. The angle that occurs between the surface of the knife blade and the horizon provides optimal sharpness for kitchen knives. By making longitudinal movements with the holder with an abrasive stone, you need to achieve a sharp edge of the knife, then turn it over to the other side and repeat the steps.
As abrasive bars, you can use ready-made products that you can purchase at a hardware store or make them yourself. For this, small rectangular glass plates, 4-5 mm thick, are used. With the help double sided tape Sandpaper of different grain sizes is glued to their surface. The cost of such bars is very low, and the sandpaper can be replaced with new sandpaper at any time. The only caution is to tighten the clamp nuts carefully, otherwise the glass may easily break.
One of the problems that arises when using such a device is rapid wear of the abrasive, since water is not used during operation. For the same reason, you should avoid too fast movements, which lead to overheating of the metal and loss of the properties of the cutting edge.
IN household There are always cutting, sawing and planing tools. During the work, the sharpness is lost, and the blades have to be restored. You can give knives and planes to the workshop, but this costs money and goes away extra time. Therefore, home craftsmen prefer to sharpen the tool.
Important! Only blades with a certain degree of hardening can be sharpened. If the cutting part has a hardness above 55 HRC, it cannot be sharpened with improvised tools.
You can buy a device for sharpening knives or other household utensils at the store. Save time, but spend a considerable amount of money - good sharpening is expensive.
By the way, there are different opinions about what the knife sharpening device is called. Emery, whetstone, whetstone, sharpener, musat...
Can these definitions refer to the same item or different products? We will talk about this and how to make such a device yourself in the article.
Since the advent of cutting objects (weapons, knives, axes), man has been looking for a way to restore the sharpness of the edge. In the Bronze and Copper Ages it was easy.
