- Why do you need a sharpener?
- How to sharpen a knife?
- Sharpening profiles
- Touchstone
- Knife sharpening devices
- Knife sharpening machine
- Not just knives...
Interest in how to make a knife sharpener with your own hands arises for a reason. Consumer qualities of manual cutting tool are increased through the use 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 scythe whetstone of a slightly greenish color lying around somewhere, 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. Blade of the "eternal" kitchen knife 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:
- 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);
- Then, without lifting the blade from the whetstone, they pull it with the butt towards you with a turn in the opposite direction, the position of the RK is dragging;
- The blade is turned over and repeat steps. 1 and 2;
- 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 a modern knife, as mentioned above, 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 - to make an ogival blade in production conditions 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.
Corner?
The sharpening angle is always given in half value?, because... Many tools and, for example, bayonet knives are sharpened on one side. Angle for knives for various purposes? maintained in the following. within:
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 camp and hunting knives with a relatively short blade.
However, this disadvantage can be turned into an advantage 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 the 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. An assembly drawing of the clamp is given, and then there are 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, in production technological innovations, which allow the use of standard profiles for the manufacture of shaped parts, are sometimes valued more expensive 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. Its appearance, device diagrams and instructions for use are shown in 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.
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:
- https://www.youtube.com/watch?v=h3HbX03YYTs – Part 1
- https://www.youtube.com/watch?v=8DKSCZIZIK4 – Part 2
Not just knives...
The original Apex sharpener is not very suitable for sharpening carpentry tools- chisel, plane iron. 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 bits of shaped planes if you put a round one in the clamps cross section, semicircular, elliptical or segmental whetstone. The main thing is that the touch spot is always point-like.
...but also scissors
Another improvement Apex sharpeners for sharpening scissors (also a necessary task 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. How to make 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 bad cutting scissors and put them into 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.
In households, the use of cutting, sawing and planing tools is often necessary. During operation, they lose their sharpness, and the blade needs to restore its original properties.
Taking your tools to workshops to sharpen them is a reasonable option, but in order not to waste money again, you can make a device for sharpening knives with your own hands.
General information about sharpening knives
The goal of any type of knife sharpening is to ensure a sharp blade. And the most important factor that affects long-term and efficient operation is the sharpening angle. The practicality of this parameter is well assessed during the work process. If you look objectively, you will notice that with a smaller angle, the knife blade results in a sharper one. But with this action, it turns out that the period of improved cutting qualities is not very long, i.e. it becomes dull faster. The sharper the knife blade becomes during the sharpening process, the more quickly it will become dull. Based on this pattern, we can come to the conclusion that the angle must be selected correctly and the value must be maintained evenly along the entire length of the edge.
It is worth noting that only those types of blades that have a certain degree of hardening can be sharpened. If the steel hardness of the cutting parts exceeds 55 HRC, then it cannot be sharpened with any available tools.
The golden rule for sharpening knives is the constant sharpening angle of the cutting edge throughout its entire length.
To achieve this, you need professionalism, skills and special equipment that will allow you to hold the tool in your hands, maintaining a given angle of inclination of each cutting edge.
In this case, you can take care of purchasing a special device, but such products are usually expensive, so you can try to make it yourself. Read more about how to make such a device at home below.
Video “Homemade design of a simple knife sharpener”
Features of using the device
Of course, a simple whetstone is suitable for sharpening a knife or the cutting edge of a plane. But its quality will not be the best. To ensure uniform removal of the metal layer and precision processing, it is necessary to use special sharpening devices.
The advantage of such a product is not only its ease of use, but also factors such as:
- The ability to fix the blades, which is quite reliable and does not cause unnecessary stress. a properly designed device does not allow the metal to be damaged during operation.
- Possibility of installing the bar at a certain angle. Thanks to this, when the cutting edge moves, the angle value will not change.
- Variation in setting different sharpening angles. With this functionality, it is possible to process various tools, even sharpening knives with a stepped structure.
Materials and tools required for the device
To make a simple and quite high-quality device, you need to take care of preparing the following workpieces and tools:
- plywood or small laminated chipboard sheet;
- steel stud with a diameter of 8 mm (the thread on it must be cut along the entire length);
- textolite or ebonite bars (alternatively can be replaced with hard wood - beech, oak, etc.);
- aluminum plate (with a thickness of at least 5 mm);
- fasteners – bolts, nuts (wing);
- neodymium magnet (you can find it on an old computer HDD).
Drawings of a device for sharpening knives with your own hands
After preparation and provision of materials, you can begin the process of assembling the device. First of all, we take plywood to use as a frame, which should rest on the mounting legs at a certain angle in the range from 15 to 20 degrees. After this, the pin we prepared is screwed into the lower part; its length should be approximately 35-40 cm. To make the mounting thread more durable, you can use glue or sealant.
We fasten an aluminum plate in the center of the installed plywood. Before fastening it, it is necessary to make a groove, which in size will correspond to the diameter of the fixing bolts. It is worth noting that we use an aluminum plate as this will help avoid damage to the steel blade of the knife.
After this, we proceed to making a lever that will allow you to secure the emery to the device. To assemble it we use the remaining part of the pin. Then we take two textolite (or wooden) blocks and, by sawing out, we make holders for the lever. The stops should be secured on one side with a wing nut.
It is optimal to provide a spring-loaded block near the handle, which will allow you to quickly change the emery stone.
As the main elements, you can use blanks from homemade bars - we glue sheets of sandpaper to the aluminum plate, and their grain size should be different. Such a device can be quite easily fixed in the lever.
home design feature- this is the presence of a hinge with a double degree of freedom. Such a device can be easily assembled using the same PCB bars. One of them should be screwed onto the threads of the vertical stud, and used as a horizontal rotary axis and a height adjuster for the lever support (this is necessary for setting the sharpening angle).
The function of the second bar, which has a horizontal hole for the lever, is that it should be screwed to the first.
Thanks to this, it is possible to ensure free vertical movement of the entire lever structure.
The knives are clamped with a plate, or fixed to the surface of a neodymium magnet. When removing the first layer with coarse types of abrasive, the blade must be securely fixed.
If it is necessary to perform fine-tuning, you can install the blade on a magnet and perform the sharpening operation with little effort. The horseshoe of magnets should be recessed at the same level as the table top and set with epoxy glue.
The manufacture of a homemade device for sharpening knives can be considered complete. It is enough to set the desired angle and sharpen the edge slowly and smoothly along the entire length of the blade.
Video “Do-it-yourself knife sharpener”
Device for sharpening knives using electric sandpaper
An electric sharpener will not only speed up the work, but also make it possible to obtain high-quality concave edge profiles on the blades, the so-called fuller sharpening. It is impossible to achieve such forms using a linear bar; therefore, these types of devices are not interchangeable, but complementary devices.
It is noteworthy that a person, working on a manual sharpening device, controls the speed and intensity of the processes performed, while the emery wheel has a constantly high rotation speed, which can negatively affect the condition of the knife.
With friction, metal surface lends itself to strong heating, which results in the “tempering” of the hardening of the steel. The material loses many properties, it becomes less hard, which leads to abrasion and the appearance of torn edges. Another problem with a “released” knife is the rapid loss of sharpness. In this regard, you need to work carefully with an electric sandpaper, bringing the blade for sharpening to the abrasive for short periods of time and taking frequent breaks to allow the knife to cool.
When working in such modes, it is quite problematic to maintain constant angles, so the tool needs to be securely fixed during such processing.
The design of such a device is quite simple to implement. In the direction of the rotating axis, there are guides on the emery along which carriages with knives move. The angles are maintained mechanically, and the forces are determined directly by the operator.
This type of device is quite easy to make with your own hands - there is no need to perform precise work for processing metal parts. The base material is actually used to make the guides.
On the workbench, near the sharpener, guides are mounted, with the help of which it is possible to change the distance from the knife stops to the abrasive. This distance affects the sharpening angle. The vertical rod must necessarily have up and down free movement regulators that have durable types of fixation of the current positions.
The knife blade should be held horizontally, pressing against the thrust element. The force in contact with the emery must be adjusted directly during operation. The processing needs to be done symmetrically; you just need to change the sides of the knife and sharpen them at the same angles.
Application this method may only be suitable for processing classic types of knives. Kitchen, hunting, hiking and other types of cutting surfaces of various tools require a slightly different approach.
A common type of design for sharpening knives is the “Jointer”
For such a device, it is necessary to use a specialized sandpaper with an end-type working surface. The guide under the carriage is placed at the bottom so that it is located away from the rotating axis. This is due to the fact that in this part of the abrasive wheel, its work is considered most effective. Guides with cutting elements move manually, the clamps are provided by the tool’s own weight.
A drawing of each structural design is shown in the image.
This type of machine was used at the beginning of the last century, and throughout this time the technology of its operation has remained unchanged. Thanks to simplicity of this device it's easy to make for your home workshop. Any components made of metal, plastic, or wood are suitable for this.
By replacing the cutting element on the jointer, you can sharpen the ice ax knives, the main thing is to maintain the correct angle, which should be flatter. Devices for sharpening scissors work on the same principle.
To sharpen a chisel and a plane knife, you can also use an electric sandpaper and locking carriages. But these types of tools are compact and can be sharpened with a mechanical tool.
There are equivalent methods - along the edges and across. In terms of quality, the processing is virtually identical; therefore, it is therefore impossible to primarily single out a specific type of device.
For factory products, blades are supposed to be adjusted transversely.
Using a similar principle, thick plywood is taken from which the frame is made. Any rollers can be used as a guide, preferably more than two. By moving the machine along the surface of the emery, the chisel blade is given an ideal shape.
If serious types of sharpening are not required, simpler devices are also suitable for minor edits.
Attach the bars with the required angles of inclination to the chisel. Place sandpaper and a piece of glass near them. Apply a soap solution to the glass surface.
You will be pleasantly surprised by the effectiveness of such devices.
For transverse sharpening, it is worth making a simpler device, where the guide element also acts as a support. The blade is attached vertically to the moving part. The only drawback of this is the fixed angle, which is set during the manufacturing process.
But, compared to a knife, the resulting deviations from ideals are not so critical.
This type of device can be used for sharpening plane knives. But due to the wide size of the blades, the process becomes somewhat more complicated. In this regard, you can use an electric sharpener that has an end working surface.
The stops are made of wooden blocks. It is important to provide for the possibility of changing angles. Clamps are provided by the operator, and semicircular sharpening can be performed, which is very indispensable for carpenters.
Naturally, this device is convenient to use for sharpening the edges of chisels. Given the high productivity rate, you will be able to restore tools even with a large number of nicks.
Now you know how you can create a homemade sharpening machine to perform all the necessary operations for sharpening knives at home.
Video “Device for sharpening various types of knives”
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 some time, which is often not enough 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. Moreover, under pressure, which is sometimes quite strong, cutting edge deformed as a result of deviation 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 treatment of the blade itself. This method requires:
- 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 term Household supplies service. It must be restored in accordance with technological standards, then there will be no problems with cutting. Knives for various purposes have their own 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, they have the same common features. 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.
- A 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. 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. In addition to the high price, such sharpeners wear out quickly working part blades.
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 such a manual knife sharpening machine. In terms of convenience, it is not far from an ordinary bar.
Sharpening machine is more complicated
For more comfortable work you will need more complex device. 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. Cut at the appropriate angle top part. 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 application. similar 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 make:
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.
Electrical installations are much more convenient, but also more expensive. 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.
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Regardless of what guarantee the knife manufacturer gives that they will not require sharpening during use, sooner or later this question will still arise before the user. It doesn’t matter whether this applies to kitchen utensils or camping accessories, because... A sharp knife is the key to success in fishing and hunting, while traveling and when cooking. Devices for sharpening knives - types and rules of use, as well as how to make them yourself - this is the topic of today’s review by the site’s editors.
The simplest device for sharpening a cutting tool is a block, and the device for its use is a clamp for the angle of the surface being sharpened
Knives can be classified according to the following indicators:
Whetstones and whetstones
A whetstone (sharpening stone) is an abrasive tool used to sharpen cutting edges household appliances and kitchen utensils, carpentry and plumbing tools.
The industry produces four types of stones for sharpening knives:
- natural– novaculite and Japanese water stone, which are expensive and difficult to use;
- diamond– most popular look products, differs in variety both in geometric dimensions, and by grain size. They are characterized by wear resistance and efficiency of use, as well as low cost;
- ceramic – modern type sharpening tool, characterized by a combination of the positive qualities of natural and diamond analogues;
- artificial– well-known types of electrocorundum or carbide are low in cost, but during use they crumble and are not suitable for finishing cutting edges.
Hand tools
- Must for sharpening knives.
Almost everyone knows what musat is, but many don’t even suspect that this is the name of this product. The reason for this is that musat, as a rule, comes with sets of knives offered for sale through trade organizations.
Musat is a rod made of various materials, equipped with a handle and characterized by the roughness of the working surface.
The roughness of the drawing is the size of the notch applied to the rod, and it is this that determines the degree of roughness of the cutting surface of the knife after processing. The musat is equipped with a rod that has a certain degree of magnetization, which ensures that metal particles formed during use reach food and kitchen utensils. Musats are classified according to:
- rod shape– round and oval, flat and tetrahedral;
- materials used– ceramics and metal, diamond and mixed designs.
Each type has certain advantages and disadvantages that determine the possibilities of using the device and its purpose.
- Manual machines.
Household manual sharpening machines for sharpening knives vary in their design, but in any of them a whetstone or whetstone acts as the main element. The impact of the abrasive tool on the cutting surface is carried out using the efforts exerted by the user. The main task performed by a manual machine is to create and maintain an optimal sharpening angle of cutting edges for the entire period of work, which is achieved by rigidly fixing the knife in a given plane. The industry produces various models of such equipment, differing in size and methods of fastening abrasives and processed knives, as well as the materials used and cost.
Household electric sharpeners do not take up much space and are very functional, because... their design, as a rule, provides various fixed sharpening angles for different types knives and other cutting tools (scissors, screwdrivers, etc.). The ability to quickly and efficiently sharpen the cutting edges of knives is very important for enterprises Catering, where the speed and quality of cooking depends on sharpening. Professional knife sharpening machines are functional devices equipped with high-quality abrasive tools that allow not only rough sharpening, but also fine-tuning the cutting edges of knives for various purposes.
Professional models, in addition, as a rule, have several operating modes that allow sharpening with different efficiency, necessary for knives made by them. various metal or ceramics.
How to properly sharpen a knife at home
Everyone knows that a knife must be sharp, and for this it needs to be sharpened, but how to do it correctly is often not known to every user. It should immediately be noted that for correct execution work required:
- Know the sharpening angles for each type of knives and other cutting tools.
- Be able to work for various equipment or using available equipment.
Sharpening angle of knives for various purposes
For knives used for various purposes, the sharpening angles of the cutting edges are different, which is determined by their purpose and nature of use.
This value is for:
- table knives - 55–60˚, because ready-made dishes are quite soft and cut easily; moreover, with a smaller sharpening angle, there is a possibility of damaging the dishes during eating;
- hunting and folding models – 40−45˚, which is explained by their versatility;
- kitchen knives – 30−35˚;
- used for professional cutting of vegetables - 35˚;
- used for professional cutting and deboning of meat – 25−30˚;
- used for professional fish cutting - 25˚.
Some types of knives are sharpened with different sharpening angles, such as those intended for slicing bread (the angle is 15˚), but this is a narrowly targeted use in which sharpening must be done quite often, because with a decrease in this indicator, the durability of the cutting edges decreases.
How to sharpen a knife at home with a whetstone
In order to properly sharpen a knife using a whetstone, you must follow several rules for performing the work:
- it is necessary to select the optimal sharpening angle corresponding to the purpose of the knife;
- the blade must be positioned in relation to the plane of the block strictly within the specified sharpening angle parameters for the entire period of work;
- Sharp and jerky movements should not be allowed, they should be smooth and sliding;
- When performing work, the block should be moistened generously with water diluted with soap or detergent.
How to sharpen using musat
The process of sharpening a knife using musat is shown in the following figure.
The work is carried out as follows:
- The musat is installed on a flat surface strictly in a vertical plane;
- the upper part of the device is combined with the sharpened edge of the knife near its handle, after which the knife moves along the rod of the grinder in an arcuate movement directed from top to bottom;
- the movements are repeated several times on both edges of the knife.
I would like to note that experienced users can perform this operation in weight, without rigidly fixing the rod of the device used.
How to properly sharpen a knife on an electric sharpener
When using models equipped with an electric drive, the basic requirements for performing work that allow correct sharpening, are the same as in the case of using a whetstone or whetstone.
But besides this, there is Additional requirements, which can be formulated as follows:
- It is not the abrasive that should be moistened with water, but the surface of the knife being processed, which is explained by the fact that water is not retained on a rapidly rotating wheel;
- the blade must not be allowed to overheat, which can lead to its damage, which occurs when the edges being processed are strongly pressed against the abrasive surface;
- can be used to rigidly fix the sharpening angle additional accessories, mounted rigidly to the body of the sharpening machine or in the hands of the user;
- When working on industrial sharpening machines, you must use by individual means protection, such as gloves and safety glasses.
In the case of using small devices intended for home use, the main requirement for sharpening is the time required to complete the operation; all the rest (fixing the sharpening angle, protection, etc.) are performed by the machine itself, according to its design.
Typical mistakes when doing DIY work
When sharpening knives on their own, many users allow typical mistakes, which can be formulated as follows:
- Creating an incorrect sharpening angle prevents the knife from being used for its intended purpose or reduces its functionality.
- Excessive pressure when working on electric models or incorrect direction and nature of movements when using a whetstone or sharpening stone contribute to damage to the surface of the knife and destruction of its edge.
- Sharpening the cutting surface without first cleaning it from dirt and foreign substances leads to the abrasive becoming washed out and damaged.
- Using only one grinding stone when sharpening cutting edges. This device It is intended only for finishing or straightening knife blades; it is not intended for basic sharpening.
- Failure to complete the sharpening operation again leads to rapid dulling of the cutting edges.
- Using an abrasive (whet stone or whetstone) of only one grit size.
Making a machine for sharpening knives with your own hands
Although nowadays you can easily buy necessary equipment and equipment designed for sharpening knives and other cutting tools, however, handicraft citizens continue to make knives with their own hands in their free time. When making a knife sharpener with your own hands, you need to decide on its type (manual or electric) and the type of abrasive materials used (block, wheel, sanding belt), as well as with available materials that will be used for the manufacture of the body of the assembled device, its frame. Consider the option of a manual sharpener using an abrasive stone and plywood as a structure frame. The appearance of the assembled device is shown in the following figure.
Every housewife sooner or later begins to get dull knives with which she cuts bread, vegetables or cuts meat. Use dull knife not only inconvenient, but also unsafe. It can fall off the product being cut at any time and cause injury. Therefore, the tool should be periodically sharpened using a special device for sharpening knives.
A wide range of such sharpening devices are offered in stores. But for one reason or another, they do not always suit the consumer. In this case, you can make a device for sharpening knives with your own hands, having previously studied the types of sharpening stones, the features of the tool and the proposed drawings.
Sharpening knives - necessary conditions
For efficient and long-term operation of a knife, the most important factor when sharpening it is angle between blade edges. During the sharpening process, it is necessary to restore the previously specified angle, which will fully comply with technological standards and quickly, freely and efficiently cut the material.
Each blade has its own optimal angle:
- for a razor and scalpel, the sharpening angle should be 10–15 degrees;
- knives for cutting bread, fruits and vegetables are sharpened at an angle of 15–20 degrees;
- multifunctional knives for various products are processed at an angle of 20–25 degrees;
- hunting and camping knives - at an angle of 25–30 degrees;
- knives for cutting hard materials - 30–40 degrees.
Without a special device, it is difficult to sharpen the blade at the desired angle. While holding the knife with your hands, it is quite difficult to ensure required tilt angle cutting tool. To facilitate this process there are special devices, which you can make with your own hands. Their designs are quite simple, and the manufacturing itself does not take much time.
There are many types of knife sharpeners, from which you can choose the one that best suits your needs.
All devices consist of two parts:
- a block of abrasive material;
- stop for attaching the knife.
You can use ready-made special stones as a bar or make it yourself.
Sharpening stones - types and manufacture
There are several types of stones on sale:
Water tools. When working with them, water is used, which saves the surface of the stone.
Oil The structure and shape of the stone resembles that of water, but its surface is the most oily.
Natural instruments are made from natural stones that undergo industrial processing.
Artificial stones are made from non-natural components.
Rubber tools can also be found on sale, but working with them is not very convenient.
To make your own abrasive bar, you can use small rectangular glass plates with a thickness of 4–5 millimeters. Sandpaper of different grits should be glued to the surface of the plates using double-sided tape. The cost of such bars will be quite small, and the sandpaper can be replaced at any time.
However, when using a glass bar, you should be very careful carefully tighten the nuts, otherwise the glass may crack. In addition, no water is used when using it, so the abrasive wears out quickly. For the same reason, when sharpening knives, you should avoid rapid movements, which can lead to overheating of the material, and, therefore, to the loss of the properties of the blade.
Device for sharpening from wooden blocks
It is enough to simply make a sharpening tool from two wooden and two abrasive bars, which should be the same size.
For greater stability of the sharpening device to its lower surface, it is recommended attach a piece of rubber.
Do-it-yourself sharpener from mounting corners
The basis for this device is a Lansky sharpener, drawings of which can be easily found on the Internet.
- metal plates measuring 4x11 centimeters;
- standard aluminum corners;
- metal rods about 15 centimeters long;
- set of nuts and bolts;
- a sharpening machine with a vice or a file;
- needle file
Instead of a sharpening machine, you can use a file, since this tool is only needed for grinding off sharp corners and cleaning the metal cutting areas.
Stages of making a sharpener:
- According to the drawing, markings are made for future holes in the plates.
- The holes are drilled and threaded.
- Using a file, all sharp corners and edges are rounded. This will allow you to comfortably use the made knife.
- Holes are made in the corner in accordance with the drawing.
- The hole for the spoke support is expanded using a needle file.
- The holes for the studs are threaded.
- The rods are inserted into the outer holes and secured with nuts of the appropriate diameter (M6).
- An M8 bolt is screwed into the wider hole, the length of which should be about 14 centimeters. A wing nut must first be screwed onto it, on top of which two ordinary nuts are screwed. The bolt in the structure will be used as a support post.
- Bolts are attached to the remaining holes, with which the knife will be clamped.
- Nuts are screwed onto the ends of the rods, a corner is threaded, which is fixed with the help of nuts. By lowering or raising the rods, you can adjust the sharpening angle.
- A thin metal rod in the shape of the letter L, a rod with an M6 thread, two holders and a wing nut are used to assemble a device that will hold the sharpening stone. The outermost holder must have a through hole for the knitting needle.
This knife sharpening device has a fairly wide range of pressing angle degrees and is most convenient to use.
Massive sharpener with stand
With your own hands, you can imitate a knife sharpening device from Apex, the drawings of which are easy to find on the Internet. Such a knife is presented in the form of a stand, on which a platform is installed at an angle, and on the side there is a support for the end of the nozzle in the form of a rod. This is very convenient device, with which you can sharpen any cutting tools very efficiently.
Required materials and tools:
Stages of work:
The sharpening angle on such a device adjustable using bar and thumb, which fixes the part at the desired height.
Each of the described devices has its own advantages and disadvantages. When choosing the appropriate option, you need to proceed from your needs and skills in such work that you will need to do with your own hands.