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 introduces into production special grinding devices.
With the help of a homemade knife sharpener, you can sharpen a knife at any angle, since the sharpening angle is adjustable independently.
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. It will most likely be much cheaper and, it is possible, much more convenient for its creator.
Necessary condition for the correct sharpening of knives
The purpose of any sharpening of a dull tool is simple and clear at first glance. But making the knife sharp is only part of the solution. The most important factor for long and efficient operation of the product is the angle of sharpening.
Figure 1. Cross section of the blade: 1 - cutting edge (RK), 2 - supply, 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 a very short time. Moreover, the sharper the knife is, the faster it becomes 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 is reduced to restoring the sharpness of the blade while maintaining right angle sharpening. In a sense, sharpening is the process of restoring a previously set angle. And it can be considered correct when it fully complies with certain technological standards and most effectively, freely and quickly cuts the material for which the knife is intended.
Therefore, each blade is sharpened at its own optimal angle for it.
However, it is generally difficult to do this without having a special device. 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 tools for sharpening knives that you can make yourself. It is worth noting that usually their designs, despite the great variety, do not differ in any increased complexity, and it takes relatively little time to manufacture such devices.
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Materials and tools needed for sharpening knives
The following blanks and tools will help to make simple and quite solid adaptations:
- wooden bars;
- a set of abrasive bars (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 are sharpening devices: a few examples
It is quite difficult to describe in detail all the grinding devices that exist today. Let's dwell on some of the most characteristic and common.
The first fixture is made from two wooden and two abrasive bars of the same size. All burrs should be carefully removed from wooden blanks with sandpaper. Then, depending on the required angle of sharpening knives, a preliminary marking of wooden bars is made. To do this, a corresponding line is drawn on the bar.
Methods for sharpening knife saws: a - jointing of the saw teeth (1 - file, 2 - block, 3 - saw blade), b - soldered 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 - vise).
Further, a whetstone is applied to the intended line in order to fix its width on the wood. On the opposite side wooden block according to the principle of mirror reflection, the corresponding lines are applied.
On the marked lines on both wooden bars 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 grindstones. After that, the abrasive elements are fixed with bolts. In order for the resulting sharpening device to be stable and not slip on the desktop, 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 shows practical experience, keeping the blade in a vertical position is much easier and more functional than driving the blade along the horizontal plane of the abrasive bar, while trying to maintain a given sharpening angle.
This device is very easy to make. To do this, you need to take a pair of ready-made, identical in size wooden squares. You can also make such square blanks yourself, providing strictly right angles in them. In several places of both squares, holes are drilled symmetrically, into which clamp screws are inserted.
Then it is necessary to mark the horizontal and vertical bars with a centimeter scale. According to it, the angle of inclination of the abrasive bar will subsequently be set. After setting the desired angle, the sharpener is rigidly fixed in the device by means of clamping screws.
Using this type of device in his practice, the grinder will have to make friends with trigonometry. With the help of 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 fixed. So, for example, with a sharpening angle x = 30 °, the horizontal extension of the bar should be 4 cm, and vertically - 15 cm.
The third version of the device for sharpening knives considered here is somewhat similar to the previous one. In this case, it is made wooden base, on which two side and one central lining are then placed. They are also made of wood, so that it is easier to cut their side edges at the angle that will be needed for high-quality sharpening.
This option involves the rigid fastening of two side plates on the base and a removable (with a screw) central plate. This pad will act as a clamp for the bars. The mating inclined faces 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 required angle for sharpening. But, unlike the previous version with square clamps, this method does not involve smooth adjustment of the angle of inclination of the grindstone. Therefore, it is possible to sharpen the knife blade here only in two rigidly fixed positions.
The following device is based on a principle that is directly opposite to the two previous options. In this case, it is not the abrasive bar that is rigidly fixed, but the workpiece to be sharpened. The sharpening element is mounted on a sufficiently long rod.
With its supporting side, the bar is attached to the vertical rack. In this case, the connection of the rod with the rack should provide free horizontal movement bar together with a barbell in different directions. Defined is set by the height at which the movable bar is fixed on the vertical stand.
Each owner will be happy to have such a homemade product that is useful for the home, because sometimes, by the sharpness of knives, they judge the owner .. There are quite a lot of methods and devices for blades. For example, it is enough to have either whetstones or carbide-tipped angular clearance devices advertised on TV. To trim expensive knives, Western manufacturers produce hard alloy bars (about 10 x 1 x 1 cm in size and in and at a price of 1500-2000 rubles). It is clear that it is difficult to call this sharpening, it is rather the removal of burrs on the blade. Of course, there are individual specialists who can make the perfect cutting edge without any adaptations, watch the video on YouTube. There are many videos on the net about this topic, the main task, solved by these devices, is the preservation of the required angle and edge width when sharpening, but I propose to make a machine for sharpening knives with your own hands.
Correct smooth sharpening is achieved by moving the grinding element at the right 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 sanding skins glued onto perfectly even and durable strips. The disadvantage of the bars is the development in the middle, which is regularly removed by editing and the high cost of the bars themselves.
For work, the device is attached with a clamp to the table. The desired angle is set by moving the slotted bar along the screw post. The blade being processed is fixed with two strips (in the second version, one five-millimeter plate was made with fastening with nuts and screws). To place the sanding paper, glass strips of ten-millimeter glass are used, glued in pairs with epoxy and a guide rod located between the strips. Photo of glass bars with glued skin and skin with GOI paste below without a rod.
The skin of a different number in the next photo.
The skin is cut into strips and glued with a weak PVA solution or rubber glue. Processing proceeds sequentially - from coarse grain to fine grain with water or oil. The movement comes only from itself. When sharpening a very curved part, the location of the knife on the fixture must be changed to ensure the same width of the shiny edge. Before sharpening and further, for ease of control, you can paint over the edge to be sharpened with a permanent wide marker. With careful work, you should get such an edge.
The device is made of what it was-Glass cost 100 rubles. last year, a set of skins in 600 r. 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 looked after.
In stores today you can choose any sharpener among a huge variety.
What are sharpening stones?
In general, there are several main types of such devices. Namely:
Oil, on the surface of which there is oil, especially to save material.
Water, similar to the previous one, but water is used here.
Natural, industrially processed.
Artificial, made from non-natural materials.
Rubber, extremely rare. Completely inconvenient to use.
Nuances in the issue of sharpening
There are moments in sharpening every knife.
For example, Japanese independent type sharpening required special attention a rather experienced specialist, since the Japanese look of steel is rather fragile. To sharpen them, manufacturers give a recommendation to use different water stones, endowed with a variety of grain sizes.
Mistresses use sharpeners bought in the store for sharpening. When using several knives, their sharpness lasts longer.
But this is very important, even though it takes a lot of time and effort.
How to sharpen knives properly?
For this, special conditions must be created. Thanks to them, the knife will remain sharp for a very long time.
Therefore, it is important to choose the right angle at which you will sharpen your knives. According to the basic rule in this matter, the smaller the angle at which the knife is sharpened, the stronger the cutting edge will be.
It is important not to forget that the next sharpening depends on the maximum sharpness. The sharper the knife, the faster it will need to be sharpened. At the same time, it will be much more difficult to make it “workable” again.
Why sharpen knives?
The purpose of sharpening is to restore the sharpness of the blade. To do this, take care of the correct sharpening angle. That is, it is necessary to restore the previously set angle that meets the standards from a technological point of view.
To check how well the sharpening is done, cut the material that is cut with the blade of this particular knife. If the material is cut elementarily, you will do everything absolutely right.
Possible problems during the sharpening process
In order to choose the right desired angle, it is important to have a certain 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 the knife with your hands during the sharpening process, it is quite difficult to achieve its ideal “sharpness” as a result.
How do you sharpen knives at home?
Sometimes it happens that the knife needs to be sharpened quickly. A block of wood, a hacksaw, sandpaper, a ceramic plate, a chisel, etc. can come in handy here.
And there are even those who can sharpen on the foundation of cement with sand. But, this method is not recommended at all. After all, there are many other and more proven ones!
The best among all - to make makeshift fixture. It is not only convenient, but also indistinguishable from the factory.
How to sharpen a planer knife
An experienced professional master who has not only knowledge, but also skills in this matter can handle knives of such a plan. The process is quite complicated actually.
At the same time, in a simple store, equipment for sharpening such a knife is quite difficult to find. You should know what will help here modern instrument, in which you can set low speed with water cooling.
It is necessary to apply a new stone, on which Smooth surface. The best will be exactly the water type of stone.
In addition, without having certain experience and sharpening skills planer knives, you can also contact the service station, where there is probably such equipment as a grindstone.
The knife sharpening machine is essential tool at home, at work or in workshops. With their help, sharpening of cutting elements of various devices is carried out - hair scissors, planer, Chef's Choice kitchen knife, cutter devices, etc. Depending on the purpose and specifications, 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 do-it-yourself knife sharpening machine allows you to process various cutting, cutter, planer knives. This is an electric unit that is equipped with a pair of grinding tools. Their role is played by tapes, discs, plates, or a combination different types devices.
- Specialized work with specific types cutting tools, therefore, they cannot be used simultaneously for processing a planer planer or Chef's Choice tools.
Machines are called specialized for:
- Scissors and knives. The sharpening angle is optimal for giving such products the necessary sharpness. Products are fed to the grinding wheel, observing the set angle.;
- Drill. These are units that allow you to return the previous cutting capabilities to drills;
- I drank chains. An electric or gasoline type saw has chains that also require sharpening. Another angle is needed here;
- Engravers. These machines use a combination abrasive wheels and engraving tools. No breaks for similar device you can work no more than 30 minutes.
When choosing a machine for circular knives, pay attention to the question of the power of the device. In this component, machines are divided into two types.
- Household. On a household sharpener designed for self made, the duration of operation without interruption cannot exceed 20 minutes. The electric drive allows to carry out small-scale grinding operations. Household models are equipped with a small list of elements and are scarce 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, a set of auxiliary devices. Important feature is that with the help of components you can set the desired angle of turning the knife.
Device Features
When purchasing a machine for flat knives, or planning to assemble a device with your own hands, 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.
- Leg-mounted structure has special mounts and work table.
- On both sides of the electric motor, abrasive elements are installed. They are located parallel to each other.
- Abrasive wheels and belts can have varying degrees of grit. Some allow you to make a rough sharpening, while fine-grained ones provide the 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 assembly is covered with a casing to protect the master from chips.
- The toolholders for the supports of the processed tools can move closer or further away 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 work on the machine yourself, be sure to make sure that the control unit is convenient to use in your particular case.
Specifications
The manufacture of grinding devices is a difficult task. 'Cause it's better to do right choice finished unit than to learn the nuances self-manufacturing. In order for a household or professional sharpening unit designed for scissors, cutter knives, planer, planer tools to meet your expectations, pay attention to:
- Power. Electric grinder can have a power of 350-1000 watts. If it's not professional, but home machine, it is enough to choose the option where the electric motor produces 500-800 watts. More powerful models will consume a lot of electricity, and the turning result will not change in any way. Simultaneously, low power will not be enough if professional machine. A professional grinder chooses devices with a power of 750-1000 W;
- Nutrition. Lay it yourself three-phase network you don’t have to, since desktop grinding devices are powered by a standard 220V household network;
- Rotational speed. To make high-quality sharpening of planer, cutter, kitchen knives, planer knife, shears for cutting, you should select the appropriate speed mode of the abrasive wheel. homemade tool can have a frequency of up to 1000 revolutions, like a household machine. A professional tool must have a speed control function, since each type of tool, steel grade has its own requirements for sharpening features;
- Grinding circle. A professional sharpener knows that the abrasive wheel plays one of the critical roles in ensuring high-quality processing of a knife. Home machines can use circles up to 150 mm in diameter. If this is a professional machine, a set of abrasive wheels is selected individually, based on the characteristics and specialization of the master;
- Landing diameter of the disk. If you make the wrong choice, the grinding device simply will not fit or will hang freely on the mounting unit. Therefore, before buying a new disc, be sure to check what bore diameter your machine has;
- Dimensions, weight. Desktop devices quite compact. But a professional tool is larger and heavier, since it is used in its manufacture. quality materials, a wider range of accessories. The main mass is created by an electric motor. There is also a manual grinding tool, only its capabilities are much lower.
Having bought a sharpener for flat knives, shearing tools, planer knives or Chef's Choice products, carefully study the factory documentation, operating recommendations.
Making power tools is a complex task. Based on the video instructions, many manage to create, if not a professional, then close to a household machine. The same Chef's Choice knives require careful maintenance. You can sharpen if you follow all the established rules.
Self-manufacturing of the machine is a topical issue. But than to do it yourself, it is 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 engineering cases.
The base must be heavy - about 3.5-5 kg - otherwise the machine will be unstable and unsuitable for sharpening heavy cutting tools. Therefore, the inclusion of steel elements in the design is welcome, for example, the base of the case can be “forged” with a corner of 20x20 mm.
From plywood, you need to cut out two parts with a jigsaw in the form of a rectangular trapezoid 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 the processing of the ends: they must be straight and exactly match the markup.
The third part is an inclined plane made of plywood planks measuring 230x150 mm. It is installed between the inclined sides of the side walls, while the trapezoids of the side walls rest on the rectangular side.
In other words, the base of the machine is a kind of wedge, but the inclined plane must protrude 40 mm in front. On the ends of the side walls, set aside two lines with a thickness gauge, indented by half the thickness of the plywood. Drill three holes in each plank for fastening the parts with screws. Transfer the drilling to the ends of the inclined part, temporarily connect the base parts.
In the back side walls are connected with a bar 60x60 mm, which is attached to the end with two screws on each side. In the bar, you need to make a 10 mm vertical hole indented 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. From above and below, screw two fittings into the hole with internal thread M10, and in them - a 10 mm hairpin 250 mm long. Here it may be necessary to readjust the lower bushing slightly if its threads do not match the stud.
Assistant device.
Remove the flat inclined part from the base - it needs to be finalized by providing a device for fixing and pressing the tool being processed.
First set aside 40 mm from the front edge and along this line with a hacksaw cut a groove about 2 mm deep. With a sectional or shoe knife, chip off the top two layers of veneer from the end of the plank to form a sample into which you can put a 2 mm steel plate flush with the common plane.
The arm rest consists of two steel strips 170x60 mm and 150x40 mm. They need to be folded together along the long end with uniform indents along the edges and make three through holes by 6 mm. The strips along these holes must be bolted together, placing the caps on the side of the upper, larger plate. arc welding bake each hat, welding it to the plate, then remove the metal deposits and grind the plate until a perfectly flat plane is obtained.
Attach the narrower striker to the notch at the edge and transfer the holes with a drill, then secure the tool rest with bolts. It can also be magnetized before installation direct current, this will help in sharpening small blades.
Locking mechanism.
The second part of the handbrake is the clamping bar. It is also made of two parts:
- Upper L-shaped bar 150x180 mm with a shelf width of about 45-50 mm.
- The lower strike plate is rectangular in shape 50x100 mm.
The details need to be folded in the same way as the parts of the armrest were folded, placing the reciprocal bar at far edge top clamp. In the center we make two holes with an indent of 25 mm from the edges of a small part, through them we tighten the parts with two 8 mm bolts. You need to start them in opposite directions, while the head of the upper (near) bolt is located on the side clamping bar. The bolt heads are also welded to the plates and pre-sanded to obtain neat fillets.
On an inclined board with an indent of 40 mm from the edge, draw a line with a thicknesser, and make one 8 mm hole 25 mm from the top and bottom edges. Connect the edges of the holes with a marking and make a cut with an allowance with a jigsaw. Bring the resulting groove with a file to a width of 8.2-8.5 mm.
Fasten the clamping and reciprocal bar through the groove in the plank. Tighten the bolt protruding from above with a nut so that the bar retains minimal mobility, then lock the connection with a second nut. To press or release the bar from below (in the niche of the base), screw the wing nut onto the second bolt.
Sharpening angle adjustment.
On the stud screwed into the base bar, throw a wide washer and tighten the nut so that the rod does not turn in the futors.
The adjusting block must be made from a small bar solid material approximately 20x40x80 mm in size. Take carbolite, textolite or hardwood.
At 15 mm from the edge, the block is drilled into a 20 mm end on both sides, the hole expands to 9 mm, then we cut the thread inside. With an indent of 50 mm from the axis of the hole made, the second one is drilled, 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, and it should also be heavily flared with a round rasp.
The block is screwed onto the stud, so it is possible to relatively accurately adjust the height of the lug without complex system screw clamps as in the original machine, which is a little more difficult to implement in practice. In order for the block to be motionless during operation, it must be locked on both sides with M10 wing nuts.
Carriage and interchangeable bars.
For a grinding carriage, you will need to coaxially weld 30 cm pieces of an M10 stud and a smooth, even bar 10 mm thick. You also need two solid blocks measuring approximately 50x80 mm with a thickness of up to 20 mm. A 10 mm hole should be made in each bar in the center and with an indent of 20 mm from the top edge.
First, a wing nut is screwed onto the bar, then a wide washer and two bars, again a washer and a nut. Rectangular whetstones can be clamped between the whetstones, but it is better to make several replaceable whetstones.
Take a light one as a basis for them. aluminum profile with a flat part 40-50 mm wide. It can be a profile rectangular pipe or pieces of an old cornice profile.
We skin and degrease the flat part, “Moment” glue on it strips of sandpaper of different grain sizes from 400 to 1200 grit. Choose sandpaper for fabric basis, and on one of the bars glue a strip of suede leather for straightening the blades with abrasive paste.
How to sharpen.
For proper sharpening, make several templates from plywood with angles of 14-20? for cutting and 30-37? for cutting edges, the exact angle depends on the steel grade. Fix the blade parallel to the edge of the handle and press it with a bar. According to the template, adjust the angle between the planes of the grinding block and the inclined board of the table.
Start sharpening with a large (P400) stone if the edge does not have the correct angle. Achieve the downhill strip to take the form of a straight strip without meanders and waves. Reduce the grit and pass on both sides of the blade first with a P800 block, and then with a P1000 or P1200 block. When sharpening the blade, pass the stone with a little effort in both directions.
After sharpening, the blade must be corrected with a “leather” bar, on which a small amount of GOI paste is applied. When straightening the blades, the working movement is directed only towards the edge (toward itself), but not against it. And, finally, a little advice: if you sharpen knives with polished blades and engraving, paste over them with masking tape so that the crumbling abrasive does not leave scratches. It also does not hurt to paste over the surface of the handpiece with self-adhesive vinyl.
