There are many ways to sharpen knives. Modern industry, promptly responding to the requests of professionals and just private craftsmen who want to use quality tool, has developed and is introducing into production special sharpening devices.
Using a homemade knife sharpener, you can sharpen a knife at any angle, since the sharpening angle is independently adjustable.
But it happens that the factory device for one reason or another does not suit the customer. In this case, you can make a device for sharpening knives with your own hands. This will most likely be much cheaper and, possibly, much more convenient for its creator.
A necessary condition for proper sharpening of knives
The purpose of any sharpening of a dull tool is, at first glance, simple and understandable. But making a knife sharp is only part of the solution to the whole problem. The most important factor for long-term and efficient operation of the product is the sharpening angle.
Figure 1. Cross section of the blade: 1 - cutting edge (RK), 2 - approach, 3 - sharpening angle, 4 - descent, 5 - butt.
The significance of this factor can be assessed in practice. It would seem that the smaller we make the angle between the edges of the blade, the sharper the knife becomes. But such an action leads to the fact that our object will not be able to demonstrate its improved cutting qualities for very long. Moreover, the sharper the knife turns out to be, the faster it will become dull, since a direct pattern appears here - the smaller the sharpening angle, the less strength the cutting edge of the blade has.
Thus, the task of high-quality sharpening of knives comes down to restoring the sharpness of the blade while maintaining correct angle sharpening. In a sense, sharpening is the process of restoring a previously set angle. And it can be considered correct in the case when it fully complies with certain technological standards and cuts the material for which the knife is intended as efficiently, freely and quickly as possible.
Therefore, each blade is sharpened at its own optimal angle.
However, doing this without a special device is generally difficult. The fact is that, holding the knife with your hands, it is difficult to ensure uniform sharpening with the given angles of inclination of the cutting edges.
To eliminate this problem, there are special devices for sharpening knives that you can make yourself. It is worth noting that usually their designs, despite the wide variety, do not differ in any increased complexity, and the manufacture of such devices takes relatively little time.
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Materials and tools needed for sharpening knives
The following preparations and tools will help you make simple and quite good devices:
- wooden blocks;
- a set of abrasive whetstones (musats);
- hacksaws (for metal and wood);
- electric drill;
- chisel;
- files;
- plane;
- clamp;
- set of various sandpaper;
- marking devices;
- screws, nuts.
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What types of sharpening devices are there: a few examples
It is quite difficult to describe in detail all the sharpening devices that exist today. Let's look at some of the most typical and common ones.
The first device is made from two wooden and two abrasive bars of the same size. All burrs must be carefully removed from wooden workpieces using sandpaper. Then, depending on the required sharpening angle of the knives, preliminary marking of wooden blocks is made. To do this, a corresponding line is drawn on the block.
Techniques for sharpening knife saws: a - jointing the saw teeth (1 - file, 2 - block, 3 - saw blade), b - sawed the sinuses with a hacksaw to a shallow depth, c - setting the saw teeth, d - sharpening the saw teeth (1 - rubber pipe , 2 — rubber safety cover, 3 — wooden clamp, 4 — vice).
Next, a sharpening stone is applied to the marked line to fix its width on the wood. On the opposite side wooden block Corresponding lines are drawn using the principle of mirror reflection.
Along the marked lines on both wooden beams cuts are made with a depth of 1 cm to 1.5 cm. Bars of abrasive material are inserted into the recesses thus obtained. When performing these operations, you need to make sure that all the grooves coincide with the sharpening stones. After this, the abrasive elements are secured with bolts. To ensure that the resulting sharpening device is stable and does not slide on the work table, a piece of rubber can be attached to its lower surface.
The second device is based on the principle vertical arrangement knife blade. In this case, the blade being sharpened will move along the abrasive bar, which is fixed at a certain angle to the horizontal and vertical surfaces. As shown practical experience, keeping the blade in a vertical position is much easier and more functional than moving the blade along the horizontal plane of an abrasive stone, while simultaneously trying to maintain a given sharpening angle.
This device is very simple to make. To do this, you need to take a pair of ready-made wooden squares of the same size. You can also make such corner blanks yourself, ensuring that they have strictly right angles. In several places of both angles, holes are drilled symmetrically into which clamping screws are inserted.
Then you need to mark the horizontal and vertical bars with a centimeter scale. The angle of inclination of the abrasive bar will subsequently be set using it. After setting the desired angle, the sharpener is rigidly fixed in the device using clamping screws.
Using this type of device in his practice, the grinder will have to become familiar with trigonometry. Using its formulas, it will be possible to accurately determine at which points of the horizontal and vertical bases of the square the edges of the abrasive bar should be secured. So, for example, with a sharpening angle of x=30°, the horizontal extension of the bar should be 4 cm, and vertically - 15 cm.
The third version of the knife sharpening device considered here is somewhat similar to the previous one. In this case, it is made wooden base, on which two side and one central pads are then placed. They are also made of wood to make it easier to cut their side edges at the angle that will be needed for high-quality sharpening.
This option involves rigidly securing two side pads to the base and a removable (with a screw) central pad. This pad will act as a clamp for the bars. The mating inclined edges of the side and central elements must have the same cut angles.
Thanks to this, it will be possible to clamp the bars at the angle required for sharpening. But, unlike the previous option with square clamps, this method does not involve smooth adjustment of the angle of inclination of the sharpening stone. Therefore, sharpening a knife blade here can only be done in two rigidly fixed positions.
The next device is based on the principle that is exactly the opposite of the two previous options. In this case, it is not the abrasive bar that is rigidly fixed, but the product being sharpened. The sharpening element is mounted on a fairly long rod.
With its supporting side, the rod is attached to the vertical rack. In this case, the connection of the rod with the stand must ensure free horizontal movement bar together with a barbell in different directions. A certain one is set by the height at which the movable rod is fixed on a vertical stand.
Every owner will be glad to have such a homemade product useful for the home, because sometimes the owner is judged by the sharpness of the knives. There are quite a lot of methods and devices for using blades. For example, it is enough to have either sharpening stones or devices advertised on TV with an angular gap made of carbide plates. To trim expensive knives, Western manufacturers produce hard alloy bars (about 10 x 1 x 1 cm in size and priced at 1500-2000 rubles). It is clear that it is difficult to call this sharpening; it is more like removing burrs from the blade. Of course, there are some specialists who can make an ideal cutting edge without any tools, watch the video on YouTube. There are many videos on this topic on the Internet and, the main task The problem solved by these devices is maintaining the required angle and width of the edge when sharpening, but I propose making a machine for sharpening knives with your own hands.
Correct, even sharpening is achieved by moving the sharpening element at the desired angle and along the desired path on the curved part of the blade. For work, in most cases, they use bars with different grain sizes or sandpapers glued to perfectly smooth and durable strips. The disadvantage of the bars is the hole in the middle, which is regularly removed by straightening, and the high cost of the bars themselves.
To operate, the device is attached to the table with a clamp. The desired angle is set by moving the slotted bar along the screw post. The blade being processed is secured with two strips (in the second version, one five-millimeter plate is made with fastening with nuts and screws). To place the sanding paper, ten-millimeter glass strips are used, glued in pairs with epoxy and a guide rod located between the strips. Photo of glass bars with pasted skin and skin with GOI paste at the bottom without a rod.
Skins of different numbers in the next photo.
The skin is cut into strips and glued with a weak PVA solution or rubber glue. Processing proceeds sequentially - from large grains to small grains with water or oil. The movement comes only from oneself. When sharpening a very curved part, the position of the knife on the jig must be varied to ensure a uniform width of the shiny edge. Before sharpening and further, for ease of control, you can paint over the sharpened edge with a permanent wide marker. If you work carefully, you should end up with an edge like this.
The device was made from what was available - glass cost 100 rubles. last year, a set of skins cost 600 rubles. Since last year it has been used about 7 times for sharpening expensive knives. Photo of a modified clamp for massive knives. 
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 maintained.
In stores today you can choose any sharpener from a huge variety.
What types of sharpening stones are there?
In general, there are several main types of such devices. Namely:
Oil-based, on the surface of which there is oil, specifically 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 matter of sharpening
Every knife sharpening has its moments.
For example, Japanese independent type requires sharpening special attention quite an experienced specialist, since the Japanese type of steel is quite fragile. To sharpen them, manufacturers recommend using different water stones with different grain sizes.
Housewives use store-bought sharpeners for sharpening. When using several knives, their sharpness remains longer.
But this is very important, even though it takes a lot of time and effort.
How to sharpen knives correctly?
For this it is necessary to create special conditions. 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 you will have to sharpen it. At the same time, making it “workable” again will be much more difficult.
Why do they 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 specified angle, which complies with the standards from a technological point of view.
To check how well the sharpening is done, cut the material that is cut by the blade of this particular knife. If the material is cut simply, you will do everything absolutely correctly.
Possible problems during the sharpening process
In order to choose the right desired angle, it is important to have some experience, without which it is quite difficult to cope in this matter. And even more so if there is no special equipment for this.
After all, if you hold a 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. may come in handy here.
And there are even those who can sharpen them on a foundation made of cement and sand. But this method is not recommended at all. After all, there are a lot of other and more proven ones!
The best of all is to make homemade device. This is not only convenient, but also hardly distinguishable from the factory one.
How to sharpen a planer knife
Knives of this type can be handled by an experienced professional craftsman who has not only knowledge, but also skills in this matter. The process is actually quite complicated.
At the same time, it is quite difficult to find equipment for sharpening such a knife in a simple store. You should know what will help here modern instrument, in which you can set low speed with water cooling.
It is necessary to use a new stone on which Smooth surface. The best type of stone will be the water type.
In addition, without specific experience and sharpening skills planing knives, you can also contact a service station, which probably has equipment such as a sharpener.
The knife sharpening machine is necessary tool in everyday life, at work or in workshops. They are used to sharpen the cutting elements of various devices - hair scissors, planes, Chef's Choice kitchen knives, cutter tools, etc. Depending on the purpose and technical characteristics, exist different types machine tools
Photo of the sharpening machine
All machines designed for sharpening tools are divided into two groups:
- Universal;
- Special (specialized).
- A universal machine for sharpening knives with your own hands allows you to process various cutting, cutter, and planer knives. This is an electric unit that is equipped with a pair of grinding tools. Their role is played by tapes, disks, plates or a combination different types devices.
- Specialized work with specific types cutting tools, therefore they cannot be used simultaneously for processing a planer or Chef’s Choice tools.
Specialized machines are called for:
- Scissors and knives. The sharpening angle is optimal for giving such products the necessary sharpness. Products are fed onto the grinding wheel, observing the established angle.;
- Drill. These are units that allow drills to return their former cutting capabilities;
- I drank chains. The electric or gasoline type of saw has chains that also require sharpening. A different angle is needed here;
- Engravers. On such machines they use a combination abrasive wheels and engraving attachments. No breaks for similar device You can work no more than 30 minutes.
When choosing a machine for circular knives, pay attention to the issue of device power. In this component, machines are divided into two types.
- Household. On a household sharpening device designed for self made, the duration of operation without interruptions cannot exceed 20 minutes. The electric drive allows for small-scale grinding operations. Household models are equipped with a small list of elements and are meager in terms of options.
- Professional. A category of expensive machines that can work for a whole day without the need for a break. The electrical unit includes a speed switch and a set of auxiliary devices. Important Feature lies in the fact that with the help of components you can set the desired turning angle of the knife.
Device Features
When purchasing a machine for flat knives, or planning to assemble the device yourself, you should definitely find out about the design features of the unit.
- The main element of the machine is Electrical engine.
- Another important component is the base.
- The structure, mounted on legs, has special fastenings and a worktop.
- Abrasive elements are installed on both sides of the electric motor. They are located parallel to each other.
- Abrasive wheels and belts can have varying degrees of grit. Some allow for rough sharpening, while fine-grained ones provide final finishing of the surface.
- An electric motor is almost always asynchronous. This is due to its quiet operation and high rotation speed.
- Diameter abrasive disc- 100-250 millimeters with a thickness of 15-32 millimeters.
- Often part of the abrasive unit is covered with a casing to protect the operator from chips.
- The supports for the supports of the tools being processed can move closer or further from the abrasive element, thereby changing the sharpening angle.
- Protective screens are the prerogative of professional machines. On household models this element is rare. The screen is a transparent plate made of plastic.
- All buttons and controls are located on the machine body. If you have to operate the machine yourself, be sure to make sure that the control unit is easy to use specifically in your case.
Specifications
Manufacturing sharpening devices is a complex task. Because it's better to do right choice finished unit rather than learning the nuances self-made. To ensure that a household or professional sharpening unit intended for scissors, cutter knives, planes, and planing tools meets your expectations, pay attention to:
- Power. Electric grinder can have a power of 350-1000 W. If it's not professional, but home machine, just choose the option where the electric motor produces 500-800 W. More powerful models will consume a lot of electricity, and the turning result will not change in any way. Simultaneously, low power it won't be enough if it professional machine. A professional sharpener chooses devices with a power of 750-1000 W;
- Nutrition. Lay it yourself three-phase network you don’t have to, since tabletop sharpening devices are powered from a standard 220V household network;
- Rotational speed. To ensure high-quality sharpening of planer, cutter, kitchen knives, plane knives, and shearing scissors, you should select the appropriate speed mode for the abrasive wheel. Homemade instrument can have a frequency of up to 1000 revolutions, like a household machine. A professional tool must have a rotation speed control function, since each type of tool and grade of steel has its own requirements for sharpening features;
- Grinding wheel. A professional sharpener knows that the abrasive wheel plays one of the critical roles in ensuring high-quality knife processing. Home machines can use wheels up to 150mm in diameter. If this is a professional machine, the set of abrasive wheels is selected individually, based on the characteristics and specialization of the master;
- Disc mounting diameter. If you make the wrong choice, the sharpening device simply will not fit or will dangle loosely on the mounting unit. Therefore, before purchasing a new disk, be sure to check what mounting diameter your machine has;
- Dimensions, weight. Desktop devices quite compact. But a professional tool is larger and heavier, since it is made using quality materials, a wider range of components. The main mass is created by an electric motor. There is also a manual sharpening tool, but its capabilities are much lower.
When purchasing a sharpening machine for flat knives, shearing tools, planing knives or Chef’s Choice products, carefully study the factory documentation and operating instructions.
Making power tools is a complex task. Based on video instructions, many manage to create, if not a professional, then at least close to a household machine. The same Chef's Choice knives require careful care. You can sharpen it if you follow all the established rules.
Making your own machine is a pressing issue. But rather than doing it yourself, it’s better to buy a professional machine. With them, your knives will always be in perfect condition. Its estimated price is from 30 thousand rubles.
Most parts for a sharpening machine can be made from literally anything, following general principle devices. As an example, let's take laminated or polished box plywood 8-12 mm thick, which was widely used in the manufacture of Soviet radio equipment housings.
The base must be heavy - about 3.5-5 kg - otherwise the machine will be unstable and unsuitable for sharpening heavy chopping tools. Therefore, the inclusion of steel elements in the design is welcome, for example, the base of the case can be “forged” with a 20x20 mm angle.
From plywood you need to cut out two parts in the shape of a rectangular trapezoid with a jigsaw with bases of 170 and 60 mm and a height of 230 mm. When cutting, leave an allowance of 0.5-0.7 mm for processing the ends: they must be straight and exactly match the markings.
The third part is an inclined plane made of plywood boards measuring 230x150 mm. It is installed between the inclined sides of the side walls, while the trapezium of the side walls rests on the rectangular side.
In other words, the base of the machine is a kind of wedge, but the inclined plane should protrude 40 mm from the front. At the ends of the side walls, use a surface planer to mark two lines with an indent of half the thickness of the plywood. Drill three holes in each board to fasten the parts with screws. Transfer the drill bit to the ends of the inclined part and temporarily connect the base parts.
In the back side walls They are connected by a 60x60 mm block, which is attached to the end with two screws on each side. You need to make a 10 mm vertical hole in the block with an indentation of 50 mm from the center, that is, 25 mm from the edge. To be sure of verticality, it is better to first drill with a thin drill on both sides and then expand. Screw two fittings into the hole from the top and bottom with internal thread M10, and in them - a 10 mm pin with a length of 250 mm. Here you may need to slightly adjust the bottom fitting if its threads do not line up with the stud.
Handy device.
Remove the flat inclined part from the base - it needs to be modified by equipping it with a device for fixing and pressing the tool being processed.
First, set aside 40 mm from the front edge and along this line, use a matching hacksaw to file a groove about 2 mm deep. Using a sectioning knife or a shoemaker's knife, chop off the two top layers of veneer from the end of the board to form a recess into which you can insert a 2 mm steel plate flush with the common plane.
The handrail consists of two steel strips 170x60 mm and 150x40 mm. They need to be folded together along the long end with even indentations along the edges and make three through holes by 6 mm. The strips along these holes need to be tightened with bolts, placing the caps on the side of the upper, larger plate. Arc welding bake each cap, welding it to the plate, then remove the beads of metal and grind the plate until a perfectly flat plane is obtained.
Attach the narrower striker plate to the notch on the edge and transfer the holes with a drill, then secure the rest with bolts. It can also be magnetized before installation DC, this will help in sharpening small blades.
Fixation mechanism.
The second part of the tool rest is the clamping bar. It is also made of two parts:
- The upper L-shaped bar is 150x180 mm with a shelf width of about 45-50 mm.
- The lower strike plate is rectangular 50x100 mm.
The parts need to be folded in the same way as the parts of a tool rest were folded, placing the counter plate at far edge upper pressure. We make two holes in the center with a distance of 25 mm from the edges of the small part, and through them we tighten the parts with two 8 mm bolts. They need to be wound in opposite directions, with the head of the upper (near) bolt located on the side clamping bar. The bolt heads are also welded to the plates and pre-ground to obtain neat roundings.
On an inclined board with an indentation of 40 mm from the edge, draw a line with a thickness planer and make one 8 mm hole 25 mm from the top and bottom edges. Connect the edges of the holes with markings and use a jigsaw to make a cut with an allowance. Finish the resulting groove with a file to a width of 8.2-8.5 mm.
Fasten the clamping and strike strips through the groove in the board. Tighten the bolt protruding from above with a nut so that the bar maintains minimal movement, then secure the connection with a second nut. To press or release the strip from below (in the niche of the base), screw a wing nut onto the second bolt.
Adjusting the sharpening angle.
Throw a wide washer onto the pin screwed into the base bar and tighten the nut so that the rod does not rotate in the fittings.
The adjusting block must be made from a small block hard material dimensions approximately 20x40x80 mm. Take carbolite, textolite or hardwood.
15 mm from the edge of the block, we drill a 20 mm end on both sides, the hole expands to 9 mm, then we cut a thread inside. A second hole is drilled at a distance of 50 mm from the axis of the hole made, but in the flat part of the part, that is, perpendicular to the previous one. This hole should have a diameter of about 14 mm, in addition, it needs to be flared strongly with a round rasp.
The block is screwed onto a pin, so it is possible to relatively accurately adjust the height of the eye without complex system screw clamps as in the original machine, which in practice is a little more difficult to implement. In order for the block to remain motionless during operation, it must be secured on both sides with M10 wing nuts.
Carriage and replaceable bars.
For the sharpening carriage, you will need to coaxially weld 30 cm sections of an M10 pin and a smooth, even rod 10 mm thick. You also need two solid blocks measuring approximately 50x80 mm and up to 20 mm thick. A 10 mm hole should be made in each bar in the center and at a distance of 20 mm from the top edge.
First, a wing nut is screwed onto the rod, then a wide washer and two bars, again a washer and a nut. You can clamp rectangular sharpening stones between the whetstones, but it is better to make several replacement sharpening stones.
As a basis for them, take a light aluminum profile with a flat part 40-50 mm wide. This can be a profile rectangular pipe or sections of an old cornice profile.
We sand and degrease the flat part, and “Moment” glue strips of sandpaper of different grain sizes from 400 to 1200 grit onto it. Choose sandpaper according to tissue based, and glue a strip of suede leather onto one of the bars for straightening the blades with abrasive paste.
How to sharpen correctly.
For proper sharpening, make several templates from plywood with angles of 14-20? for cutting and 30-37? for chopping edges, the exact angle depends on the grade of steel. Fix the blade parallel to the edge of the tool rest and press it with a bar. Using the template, adjust the angle between the planes of the sharpening block and the inclined board of the table.
Start sharpening with a large (P400) whetstone if the edge does not have the correct angle. Make sure that the descent strip takes the form of a straight strip without bends or waves. Reduce the grit and go along both sides of the blade first with a P800 stone, and then with a P1000 or P1200 stone. When sharpening the blade, apply the whetstone with slight force in both directions.
After sharpening, the blade needs to be straightened with a “leather” whetstone, onto which a small amount of GOI paste has been applied. When editing blades, the working movement is directed only towards the edge (towards you), but not against it. And finally, a little advice: if you sharpen knives with polished blades and engravings, cover them with masking tape so that the crumbling abrasive does not leave scratches. It also wouldn’t hurt to cover the surface of the tool rest with vinyl self-adhesive.
