Interest in making knife sharpeners with your own hands arises for a reason. The consumer qualities of hand-held cutting tools are enhanced through the use of modern materials and technologies for blade manufacturing and precision factory sharpening. At the same time, the price of the product increases, but it is becoming increasingly easier to ruin a fairly expensive item with primitive sharpening. Therefore, various household devices for sharpening knives are no longer needed only for convenience. To understand why a knife sharpener is still needed and how to make it correctly, you will have to start with the ideology and evolution of the knife.
Why do you need a sharpener?
A living relic of our days – Finnish hunting knife. Not a gangster Finn sometimes weird shape, and a Finnish-type hunting knife, on the left in Fig. 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. Finnish hunters did not care about this: a blade of such hardness can be sharpened (sharpened) by beating on 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, but extreme situation the durability of the blade, combined with the viscosity 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. The blade of an “eternal” kitchen knife is structured like a rodent’s incisor: in longitudinal layers, the hardness of which decreases from the core outward. In any case, you have to sharpen the knife less often, but chipping is definitely ruled out - the blade immediately becomes discolored.
How to sharpen a knife?
For these reasons, push-pull sharpening technology (push-pull sharpening or push-pull sharpening technique) was invented long ago:
- 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, turning it reverse side, the position of the Republic of Kazakhstan 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.
Angle α
The sharpening angle is always given in half the value α, because Many tools and, for example, bayonet knives are sharpened on one side. For knives for various purposes, the angle α is maintained as follows. within:
- 10-15 degrees – medical scalpels, straight razors, knives artistic carving.
- 15-20 degrees – pastry knives (for cakes) and vegetable knives.
- 20-25 degrees – bread and fillet knives.
- 25-30 degrees – hunting, hiking, survival knives.
- 30-35 degrees – general purpose household knives.
- 35-40 degrees – carpentry tools, shoe knives, axes.
One and a half
Sharpening knives, except for special ones, is done almost exclusively with a one-and-a-half profile, on the left in Fig. One-and-a-half sharpening is so named because the flat edge of the blade (descent) is formed during the manufacturing process of the blade and cannot be sharpened. In fact, sharpening a knife with one and a half sharpening is no more difficult than sharpening it with a simple wedge. One-and-a-half sharpening is optimal for a knife that works with a variety of materials, and making a knife sharpener with one-and-a-half sharpening is much easier than using a faceted sharpening.
In the center and on the right in Fig. The stages of blade sharpening and the numbers of abrasives used on them are shown. The abrasive number corresponds to the number of its grains per 1 square meter. mm surface. The finishing stage has some features:
- Hunting and camping knives are not supplied. This makes it easier for them to cut hard things (for example, bones) with broaching (with filing). In addition, if you accidentally cut yourself, the slightly lacerated wound stops bleeding faster, heals more easily, and there is less danger of infection getting into it.
- After abrading, the blades of straight razors, shoemaker's knives and for artistic carving are brought to mirror smoothness on a leather whetstone with GOI paste.
- Guiding and fine-tuning of blades kitchen knives can be combined into one operation with abrasive No. 800-1100.
Touchstone
A homemade knife sharpener will be much more convenient and accurate if you do not buy a whetstone for it, but make it from a piece of square corrugated pipe 200-300 mm long (on the left in the figure below) or wooden block.
The edges of the base are covered with sandpaper, respectively. numbers. Glue – stationery adhesive stick. The advantages of a skin-based donkey are obvious:
- Much cheaper than an emery block.
- Can be made with 4 numbers of abrasive, while sanding blocks have a maximum of 2 sides.
- Wear (depletion) of the abrasive is possible no more than the thickness of the abrasive layer of the sandpaper; the waviness of the RK due to the rotation of the whetstone on the sharpener rod (see below) is also no more than this amount.
- As a result, the sharpening angle error due to the development and rotation of the whetstone does not exceed fractions of a degree.
- The chip from the pipe can be put on a threaded rod (in the center in the figure), which makes changing the abrasive faster and easier.
- A touchstone made from a pipe or a wooden block is held in any clamps under an emery block no worse than the last one, on the right in Fig.
Knife sharpening devices
The simplest manual knife sharpener is an angular frame in which a whetstone is clamped, pos. 1 on next rice. The same type of “company” is on sale, and this is marketing: they want up to $50 or more for a plastic board with inclined nests for whetstones. Touchstones – non-standard sizes; regular ones won't fit into the holes. If you are used up, you need to buy more original ones. Price - you understand. And all the convenience - holding the blade strictly vertically when sharpening is still easier than maintaining its angle of inclination.
The use of a simple knife sharpener can be further simplified to the point where no skill is required if you supplement it with a sliding shoe with magnetic holder for knife, pos. 2. Sharpening procedure in this case track:
- Knife right hand hold by the handle, turning in the direction of movement according to the curvature of the blade;
- With the fingers of the left hand, except the thumb, press the shoe to the whetstone;
- With the thumb of the left hand, they press on the butt of the blade, pressing the RK to the abrasive.
The function of maintaining the angle of inclination is removed from the operator, and the rest are distributed between 2 hands. In this case, the skill of sharpening with your own hands is developed immediately, but you need a holder that firmly holds the knife and at the same time allows it to slide over its surface. You can make one from the magnets of the write-read head carriage drive from an unusable HDD drive (hard drive). The “screw” carriage drive magnets are niobium, thin, flat, smooth and very strong (shown by red arrows in position 3). They are glued with DIFFERENT poles onto a steel strip, the force of attraction of the blade will then double. And to ensure sliding, the holder is covered with a fluoroplastic film 0.05-0.07 mm thick. PET from bottles will also work, but it is thicker and the attraction will be weaker. Polyethylene is not suitable, it will wear out immediately.
Note: remember this holder, we will need it later.
L.M.
The use of a manual knife sharpener such as Lansky-Metabo, pos. 1 in Fig. The diagram of its device is given in pos. 2, and the procedure for use is in pos. 3. The disadvantage of the Lansky-Metabo sharpener is the instability of the sharpening angle along the length of the blade: a rod with a touchstone is driven along it. The offset of the touch point is constantly changing, because it describes an arc of a circle, and the blade has a different configuration. Resp. The angle also “floats”. Therefore, the Lansky-Metabo sharpener is used primarily for sharpening camping and hunting knives with a relatively short blade.
However this disadvantage it is possible to turn it into dignity if the blade is clamped in the terminals with the root part A (at the handle) and the tip slightly turned away from you, pos. 4. Then the sharpening angle at the root of the blade will be greatest, which is optimal for processing hard materials or using 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 that make it possible to use standard profiles for the manufacture of shaped parts are sometimes valued more than serious inventions.
Note: on the trail. rice. An assembly drawing of the Serjant sharpener is given. Regarding the inconvenience of fastening in a vice, see above.
Knife sharpening machine
The most advanced household manual sharpener today is a knife sharpening machine Apex type. His appearance, device diagrams and instructions for use, see Fig. Apex can be made with a continuously variable sharpening angle (item 2) or with fixed angles like Lansky-Metabo (item 3). Normally on Apex they work like on Lansky-Metabo (item 4), but for more precise sharpening other options are possible, see below.
Homemade version of the Apex sharpener - Skomorokh knife sharpener
In 2016, the desktop modification of Apex by Ivan Skomorokhov made a splash in the RuNet, perhaps no less than the bubafon stove once did, see fig. on right.
Skomorokh sharpeners are much simpler than the prototype and are in no way inferior to it in functionality.
How to make a knife sharpener Skomorokh, see video:
Not just knives...
The original Apex sharpener is not very suitable for sharpening carpentry tools- 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 pieces 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 modification of the Apex sharpener for sharpening scissors (also a necessary thing in the household) is shown in Fig. on right. The total work required is a couple of pieces of angle or galvanized scraps and 4 additional holes in the sharpener table. For the process of making your own attachment for sharpening scissors for the Skomorokh sharpener, see next. video:
Video: sharpening scissors, attachment to the sharpener Skomorokh
Finally, about scissors
Before you grab your poorly-cut scissors and stick them in the sharpener, check to see if the hinge is loose. Open the scissors and look at them from the side. Do you see how the tip is turned with a screw towards each other? That’s why scissors cut: the point of contact of the blades when cutting moves from the roots to the ends. And therefore it is difficult to cut with scissors with your left hand: turning the ends is designed for the kinematics of your right hand. And if the hinge of the scissors is loose, the blades will move away from each other and will not even be able to cope with paper. In this case, you just need to tighten the riveted joint with a hammer and the screw joint with a screwdriver.
Almost everyone home handyman cutting tools are available. Over time, the cutting edges lose their former sharpness, and working with such a product becomes unbearable. There are two options for solving this problem: have the tool sharpened and pay a lot of money, or assemble a knife sharpening device yourself and sharpen the products yourself.
Causes of blade dulling
The dulling of the blade can be explained as follows. During cutting, the blade is exposed to the smallest abrasive particles, be it fruits or vegetables. The cutting edge of the blade gradually wears off and the knife becomes dull. Another reason is to hold the blade when cutting at a certain angle.
Some areas of the blade are subject to increased stress and increased wear.
There are types of knives that are impossible to sharpen yourself due to the textured blades. Also, knives made from ceramics cannot be sharpened. But, as a rule, the quality of the steel in such products is high, and they rarely become dull. There are a variety of knives of low quality, and they have to be sharpened very often. As practice shows, if the steel is of poor quality, then sharpening will solve the problem for a while, and then the blade will become dull again.
To sharpen knives you will need abrasive wheels. If it is not possible to purchase ready-made circles, you can make them yourself using wooden blocks and sandpaper of different grain sizes.
The standard sharpening angle is 20 - 30 degrees. It is quite difficult to maintain the angle during sharpening, and therefore it is necessary to make a simple knife sharpener, in which it is not necessary to maintain optimal angle. The basic rule in this process is maintaining a precisely specified constant angle. No force required here. The main thing is that the block and blade meet at a certain angle. This is the basic rule of the sharpening technique.
Basic mistakes
As it may seem at first glance, sharpening is simple, but if you delve into the process itself, you will notice quite a large number various nuances. Most people make simple mistakes when sharpening knives, which leads to uneven sharpening or damage to the knife. Common Mistakes when sharpening:
- The cutting edge was not sharpened. As a result, small burrs form on the sides, which temporarily give sharpness to the blade, and after working with the knife for a short time, the blade again becomes dull. To prevent this problem, you should carefully sharpen both edges, and then, as you sharpen, use sandpaper or a circle of different grain sizes.
- Presence of paint, oil, dirt on the tip. The bottom line is that during turning, fat, dirt, oil and other components mix with grinding abrasives and lead to scratches and microchips of the blade. After such sharpening, the blade quickly becomes dull.
- Pressure plays an important role. You need to remember one simple rule: sharpness does not depend on the force used, but on the duration of sharpening. Excessively strong pressure leads to chipping of microparticles from the blade and poor sharpening.
- Incorrect angle selection. The angle may vary depending on the grade of steel and the purpose of the tool. For home kitchen knives it is 20 - 25 degrees. For other types of blades that will have to withstand heavy loads and work with hard materials, the angle will be 40 degrees.
By following simple but at the same time appropriate rules for sharpening, you can not only save time, but also not damage the product.
Sharpener "Domik"
A good tool for sharpening knives. Despite its simple design, the sharpener does its job well. This structure consists of a bar rectangular shape, the upper edge of which is made in the form of a gable roof. The angle of inclination of one face is 20 - 25 degrees, which is optimal. The product must be installed with a blade close to one of the roof ridges, then take an abrasive wheel or a block with emery and move along a horizontal line. This ensures a constant angle of inclination, which leads to uniform sharpening of the blade.
There are also complex designs homemade sharpening machine. For manufacturing you will need the following materials:
- A piece of board measuring 500x150x20 mm.
- A metal pin with a thread that will serve as a guide for the bar.
- M8 bolts and nuts and wood screws.
- Clamping nuts or wing nuts.
- Ordinary PCB or plexiglass, which will serve as a substrate for the knife and a kind of movable frame.
- To attach the knife, use a neodymium magnet. The usual one will not work, since its downforce is quite low.
The board must be cleaned, processed, and then made into a rectangle. Another board should be made rectangular in shape, which will serve as a stand or support. Its height should be such that the slope of the main board is 20 degrees. You can fasten them together with wood screws. Then attach the resulting structure to the workbench or cut out a tabletop in advance, to which one of the studs will be attached. After securely attaching the pin to the tabletop, you need to take a 200x100 block and make two holes in it: one for the main pin, on which the movable carriage with the sharpener will be attached, and the other for the pin, which is attached to the tabletop.
Now you can begin assembling the carriage with the sharpener holder. For the pin that will hold the carriage, you need to make two clamps from wood, plexiglass or metal. Drill holes in the clamps, put them on the stud and secure them on both sides with nuts. The carriage will rotate freely along its axis.
The next step is to install a neodymium magnet on a previously prepared plate. It is necessary to make a longitudinal groove in it so that the tripod can be moved up and down. Drill a hole in the middle of the frame and insert a bolt with a nut, which, in turn, will press the plate. You can simply glue a neodymium magnet to the end of the plate to hold the knife.
The homemade device is ready for use. It can be used to sharpen chisels and planes.
It should be noted that sharpening is carried out without water, so the abrasive paper or wheel will wear out greatly, but this option is quite suitable for sharpening knives and tools at home.
Homemade knife
If the farm has a sharpening machine, it will make the process easier, but there is one circumstance. When sharpening on a machine, it is almost impossible to apply even pressure on the knife. Therefore, it is possible to make a device for sharpening knives, which will serve as a guide for the blade and ensure uniform pressure. The result is a simple but effective electric sharpener. To make it you will need the following components:
- Beam.
- Four bolts or four studs with M8 thread.
- Four lambs.
- Self-tapping screws for wood.
Opposite the electric sharpener, a guide is attached along which the slider will move. The guide itself can be attached to the workbench or a pre-made frame can be made. It must be mobile. To do this, you can cut a longitudinal groove in the frame and secure the tripod with two studs. Then take two bars, drill holes on the sides, insert studs and tighten them with screws on both sides. The next step will be the mount on which the cutting product will rest. This can be done using small pieces of timber, which should be attached to the sides of the moving carriage.
After this you can start sharpening. Set the movable carriage to the desired height and clamp it with the thumbscrews. Move the tripod itself to the required distance, securely fasten it and sharpen the product by moving the knife along the side guides.
Sharpener LM
If in the future you plan to do professional sharpening of tools in large quantities, then you can make a sharpener called: Lansky-Metabo. Fixture drawings for sharpening knives with your own hands look like this:
If the product is clamped in the clamps with the root part, the sharpening angle will be greatest. A knife with this angle can be used as a “cleaver” and for processing hard wood. You can also easily sharpen knives using a jointer. Knife clamps can be made from angle iron or wood. The disadvantage of this design is the complexity of assembly and the large number of parts.
If it is not possible to assemble a complex tool for sharpening knives, then you can make do with improvised means and make manual knife sharpeners. A simple sharpener can be made from a corner frame in which a whetstone is mounted.
If you add a sliding carriage to the sharpener, you won’t have to hold the knife at a certain angle, which, in turn, will have a good effect on sharpening the blade. To make a movable carriage you will need a triangular block and a magnet. It is best to use a neodymium magnet, which allows you to attract the knife and fix it securely. If such a magnet is not available, then you can take components from the HDD (hard drive).
Before you give a knife or other product for sharpening, you should familiarize yourself with the material, which will help not only in making a sharpener with your own hands, but also save a certain amount. The main aspect is to gain additional experience, which will be useful in the future.
I continue to sharpen the knife. I've already shown mine homemade device to make slopes (tapering surfaces of the blade). At the same time, I made a polishing disk, sewing several disks together so that they would not diverge. Next, the task was to sharpen the knife - to make cutting edges that form the cutting edge.
An attempt to sharpen it with a whetstone did not give me the result I needed, because the metal of the blade is hard and sharpening takes a lot of time. Therefore, I decided to make a homemade device similar to the one I made for forming slopes.
I installed the main part of the device - the angle - at the point where the surface of the grinding wheel is at an angle of 75 degrees to the vertical line. I used a regular corner piece and made a hole in the central part. I aligned the corners at 90 degrees so that the existing small semicircle would not interfere with work. I drilled a hole in the center for a 16mm bolt. A nut in the form of a clamp was welded to the bolt. A channel is installed at the bottom, the structure is pressed with a bolt and nut of 12.
The device can be raised or lowered with two nuts on the top bolt. When ascending, the sharpening angle will be larger, and when descending, it will be sharper (smaller). Using a clamp, the device can be moved towards the disk (for example, when the disk is ground down) or moved away from it.
The design can be simplified and you can install one long bolt so that you can immediately make descents or, lifting it higher, sharpen the knife to the desired angle.
The cutting edges are very smooth, as if made on milling machine. If you correct the edges on a small block, the knife will be razor sharp. The result is an almost perfect sharpening. The advantage of this device is that it is very simple design, which can be assembled from scrap materials.
The myth about supposedly self-sharpening knives was quickly shattered... About everyday life. This is not surprising, the laws of physics are laws of physics, and even marketers, so to speak, are powerless against them. If there are no sharpened knives in the house, if you remember the famous bard, there is nothing good. Today the editors of the site will help solve the problem of dull blades and tell you how and with what you can properly sharpen a knife at home. We will introduce our readers to different types devices for sharpening knives, we will tell you about their effectiveness, and also teach you how to make a simple sharpening machine at home.
Read in the article
Types of devices for sharpening knives
A whetstone for sharpening knives is probably the very first device of this type. A simple, and, most importantly, affordable tool has been successfully coping with its task for many millennia.
To this day, the classification of machine tools depends on this once uncontested sharpener. Depending on the type of abrasive material, they can be:
- bars;
- sharpening stones.
By drive type:
- manual;
- electrically driven.
By place of use:
- domestic;
- professional.
However, in the modern world, a whetstone can only sharpen a simple hunting knife. In other cases, the quality will leave much to be desired. In addition, only soft metals can be sharpened with a stone; if the cutting part of the blade has a hardness above 55 HRC, you cannot sharpen it with improvised means.
Important! Each type of blade has a different edge angle. And during sharpening it must be held along the entire length of the processed surface of the product.
Some types of modern sharpening stones are still used today. An example of this is natural stones - Japanese water stone (we showed it in the photo above) or American “Arkansas”. Master sharpeners even conduct special master classes on sharpening knives using natural stone. It is interesting that before the processing process it is soaked in water, sometimes with a soap solution, and after work it is dried. The whole process resembles a sacrament for initiates. So it should come as no surprise that these grades are overly expensive and most sharpening devices use artificial abrasive surfaces.
Knife sharpening stones
These are artificially turned bars with an abrasive coating, which are suitable for manual sharpening of both carpentry and plumbing tools, as well as kitchen knives.
The bars, depending on the material from which they are made, can have varying degrees of wear resistance and grain size. Let's consider the main types of materials that are used in the manufacture of sharpening stones:
- Natural stones, such as novaculite or Japanese water stone. Working with such a tool is not very easy. They require certain skills and craftsmanship.
- Diamond(with diamond coating) – can be different shapes and graininess. Wear-resistant. Reasonable price.
- Ceramic. Refer to more modern look whetstones for sharpening. They combine the strength of diamond coating with the hardness of natural stone.
- Artificial: electrocorundum or carbide. Quickly grinding abrasive is of low quality and the same price.
Artificial abrasives are created by mixing diamond powders of different fractions, as well as electrocorundum and carbide.
Important! Of great importance in this case is the material used to glue the rock together, as well as the percentage of all elements. The stronger and better the composition (this also applies to the particles themselves), the more durable the sharpening abrasive will be.
Moreover, there are two types of bonding of elements - galvanic bonding and soft bonding. In the first case, the crystals are glued strictly to the surface of their base, made of a nickel alloy. In fact, the crystals are located in a very thin layer on the bar. A soft binder is a chaotic arrangement of binding and abrasive elements. The second type is less wear-resistant.
Sharpening stones for knives
If we talk in more detail about sharpening stones, we need to talk about the main types used in such tools, this will help you understand the process in detail and understand how to sharpen a knife correctly. But before talking about them, it is impossible not to mention the stages of sharpening, which in this context will play a decisive role in the description different materials and machine tools.
| Stage | Description | Illustration |
| Sharpening | Restoring a blunt edge without adjusting the sharpening angle. |  |
| Finishing | Grinding the edge with fine grain abrasives. |  |
| Edit | Polishing bevels and cutting edges with a ceramic pencil, GOI paste or on a leather belt. |  |
| Resharpening (deep sharpening) | Full recovery desired angle sharpening, blade profile geometry and eliminating chips on the edge. Most often, such work is carried out on special machines. |  |
Let's move on to a description of the main options for sharpening stones.
Japanese water stones Waterstone
They are used equally effectively at all stages of sharpening. There are artificial analogues (ceramic based), but professionals use original, natural materials. Stones require special care, because most important rule masters - a perfectly smooth surface of the grindstone.
A comment
Ask a Question"To check the level of the stone, use a simple method. Wet the timber and place it on a piece of paper on a flat surface. The imprint will allow you to evaluate the level of the stone.
"Novaculites, or “Arkansas”, “Turkish”, “Belgian” stones, are natural schists and chalcedony interspersed with tiny particles of garnet and quartz. Today, both natural stones and their artificial substitutes are used.
Important! Stones only work in combination with a special oil lubricant. The extraordinary and unique structure of the stones allows them to be used on different stages processing.
Musat for sharpening knives
Musat is a kind of file, most often installed vertically. The peculiarity of this tool is that its surface is magnetized, which means that metal flour will not fall on you.
Musats come in different shapes: round, faceted, flat with beveled edges Each variation has its own merits. For example, round musat weighs little, but oval sharpens better, since its edges provide more complete contact with the surface being processed. Tetrahedral ones are more universal; here you can better refine the required sharpening angle.
Household manual knife sharpening machines
We can talk for hours about the options and varieties of hand-held machines used in everyday life. These include the usual home mini-sharpeners, known to almost everyone, and more specific devices with a polishing wheel.
The easiest way to work is with mini-sharpeners that control the stroke of the tool. In this case, the degree of sharpening depends on the effort the person makes.
Household electric knife sharpening machines
Electric sharpeners are more convenient. Working with them saves time. Most often, such drive machines have different operating modes, which are regulated by switches.
Typically, such machines are compact, safe, simple and reliable, since all grinding wheels hidden inside the case. In this case, the sharpening angle is adjusted by a special spring, which completely eliminates errors in sharpening.
Professional manual sharpeners for sharpening knives
Professional hand tools are a bit like a carpenter's vice. The object to be sharpened, the knife itself, is clamped with special clamps.
The sharpening machine itself is mounted on a stop. It is very important here to properly secure the machine and avoid the device slipping during sharpening.
A comment
Tool selection specialist at VseInstruments.ru
Ask a Question“If you do not have the skills to operate this tool, it is better to use automatic sharpeners. In addition, such a machine cannot be assembled without certain knowledge.
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Professional electric knife sharpening machines
Professional machines are distinguished by their versatility. Usually this is a device with a massive abrasive disk. Such tools allow you to sharpen not only knives, but also locksmith tool, for example, planes and chisels.
The combination of low speed and constant cooling gives high-quality processing products already at the stage of formation of the cutting edge. And at the final stages of work they provide the blade with razor sharp. IN professional instrument A large number of attachments and replaceable discs are provided. Moreover, the clamp where the blade is secured can move freely along the support in the horizontal direction. Moreover, you can adjust the sharpening angle.
How to sharpen a knife correctly
For high-quality sharpening of the machine, you need experience and certain knowledge. Let's start with the basics.
Optimal sharpening angles and degree of sharpness for kitchen knives
It's no secret that there are a lot of knives for different materials. A good housewife has her own knife for vegetables and meat. Let's look at the correct sharpening angles for different tools.
| Tool type | Sharpening angle |
| Razor and medical scalpel | 10-50° |
| Professional for chefs | 20-25° |
| Universal | 25-30° |
| For complex work | 25-30° |
| Kitchen cutlery | 55-60° |
| For fillet | 15-20° |
| Home universal | 30-35° |
| Deboning and cutting | 25-30° |
| Professional for fish | 25° |
| Professional for vegetables | 35° |
| Hunting and “Swiss” (spicy) | 30-35° |
| Hunting and “Swiss”, resistant to blunting | 40-45° |
For your information! The sharpest knives are considered to be blades with a sharpening angle of 50°; such versions, with a certain grade of steel, can cut nails. When sharpening knives, you can vary the angle at your discretion within the mentioned range.
In general, the sharpness of a blade depends on the shape of the blade. And it, in turn, must correlate with certain clear correspondences of the relationships between the blade and the blade.
How to sharpen a knife at home with a whetstone
The process is simple, but quite painstaking. Without sharpening experience, trying this process is pointless. Typically, craftsmen use two sharpening stones with different abrasive densities - with a large grain and a fine one.
The process of sharpening a knife or any tool does not require any outstanding skills or knowledge of special movements. In most cases, sharpening a knife, even the most original and expensive one, can be done with ordinary abrasive stones or sharpening devices. But under one condition - you must try to follow the recommendations of specialists involved in sharpening tools in industrial conditions.
How to sharpen a knife
There may be several answers to the question of how to sharpen a knife:
- You can restore the tool using a sharpening stone or a set of triangular files with a fine notch;
- Use a knife sharpener. The main difference between this method and the previous version is that the support under the blade allows you to maintain a stable sharpening angle of the edge;
- Use a knife sharpening machine.
For your information! Despite what hand sharpening enthusiasts may say, a properly configured automatic or miniature machine will cope with the formation of edge angles much better than a hand whetstone.
For ordinary people Sharpening knife edges is an everyday task, and if the choice is between using a DIY knife sharpening machine or sharpening a blade by hand adjusting the cutting edge for several hours, then common sense would probably choose a sharpening machine.
How to get a sharp edge on a kitchen knife
The movement and tilt of the blade relative to the block is not as obvious as it might seem at first glance. To correctly understand the sharpening technique, you can use the video about sharpening knives:
For your information! Modern knives made from a wide range of carbon and alloy steels. Hardened forged steel must be sharpened with an abrasive stone, and relatively tough stainless steel only with a triangular file.
Blades made of soft and tough steels with low chromium and carbon content can be sharpened with a file, while at the same time they very quickly clog the surface of the abrasive stone. Flexible forged blades must be fixed with a stop and sharpened with a block using sliding movements. Regular use of a whetstone for sharpening kitchen knives leads to greasy surfaces, which must be restored by grinding.
The old device for sharpening forged knives was made in the form of two wedge-shaped bars made of bog oak. The bars were placed on both sides of the blade so that the cutting edge remained free, the “sandwich” was tied with twine and sharpened with an ordinary whetstone to a razor sharpness. Wedges made of hard wood made it possible to correctly guide the block and obtain the required sharpening angle.
According to the recommendations given, it is carried out manual sharpening plane knives. Fine-grained sandpaper is glued onto thick glass, but the beveled part of the cutting edge is placed on the surface of the abrasive and sharpened in a circular motion.
Sharpening a ceramic knife is more difficult; you can manually trim the cutting edge with a diamond-coated needle file, or use a special grinding paste.
Homemade knife sharpening options
The simplest device for sharpening knives is shown in the diagram. To make it, you will need a block of hard wood, the upper plane of which is sharpened at an angle to form the cutting edge. This solution helps to maintain the correct edge processing angle. To make sharpening the blade more convenient, you can screw a pair of self-tapping screws to fix the blade into the plane of the block.
For sharpening planing knives You can make the attachment for the sharpener shown in the photo with your own hands. This solution simplifies the process and allows you to sharpen the blade as sharply as possible, but the lack of mechanization requires a certain skill and dexterity from the master.
Devices and machines for straightening and sharpening knives
Sharpening knives is certainly a creative activity that requires a lot of patience and skill. But is it worth spending time and energy on solving a task that can be successfully handled by a specially designed machine or device for sharpening knives? If for knives, household tools, for example, planing devices, kitchen or cutting blades, you can try to restore the cutting edge of the blade with your own hands, then for industrial volumes even sharpening devices will not help. You will need a powerful and productive machine.
Machines for sharpening the blades of cutting knives
The highest form of a sharp knife blade are non-rare models with chrome-plated blades and handles made of rare wood. These are more like museum exhibits or cheap imitation of them. An example of the sharpness of a blade is considered to be a carving or boning knife, which is used to cut raw meat and skins for 12 hours a day. It is under such conditions that the edge of a forged knife made of high-quality steel becomes dull unusually quickly.
For small volumes of cutting work, knife blades can be sharpened on simple machines with automatic control cutting edge angle.
For cutting areas of meat processing plants, professional equipment KNECHT USK 160 is most often used. The machine has a high degree of versatility, which allows you to sharpen the entire range of cutting tools, from fillet blades to cutting scissors.
Machines for sharpening cutting elements of carpentry tools
Sharpening knives for woodworking machines requires the mandatory use of specialized machine equipment. If you sharpen a relatively short blade of a household knife or hand plane Can manually using the simplest device, then long and sharp blades jointers and planers must be sharpened using a mechanical drive to feed the sharpening tool.
If you try to sharpen a tool with your own hands on a sharpening cup without support and guide slides, areas with different sharpening angles will form on the cutting edge. When processing wood, this leads to the formation of an uneven wavy surface of the board or solid wood.
Small flat knife blades can be sharpened to a simple machine vertical type.
Circular saws are usually sharpened on machines equipped with a divider and a rotary table.
Universal sharpening machines
In small carpentry shops, woodworking areas, and repair shops, universal sharpening machines are used that can sharpen a very wide range of cutting tools, including sharpening guillotine knives.
As an example, we can cite the desktop model of the VZ-319 machine. Thanks to the rigid bed and correctly selected gear ratios of the mechanical drive, the unit can sharpen almost any tool, from plane blades to cylindrical cutters.
Conclusion
Sharpening knives has long gone beyond the scope of craftsmanship into the category of an ordinary mechanical operation. A large number of various machines and devices, tabletop machines and automatic machines are capable of performing difficult work within a few minutes. A high-quality sharpener purchased once in your life can last for several decades, eliminating the hassle of sharpening knife blades.
