The sharpest dagger. How to distinguish a sharp knife from a dull one? Optimal knife sharpness according to the Tojiro scale. What determines the so-called sharpness of a knife?

Have you sharpened your knife enough or not enough? How can you tell if a knife is already sharp or still dull? And is there a certain degree of sharpening that will be universally good for any knife? Answers to these questions can only be obtained by understanding what makes a knife cut well and the dangers of having a sharpening angle that is too small.

What determines the so-called sharpness of a knife?

We call a knife sharp when it cuts through (or cuts through) some substance without much effort on our part. Of course, if it is designed to work with it at all. But why does this happen?

What usually shines when viewed from the side of a blade is what we call the cutting edge or, even more incorrectly, the blade. In fact, it is more correct to talk about leads. Leads are very narrow planes that converge at one point along the entire length of the blade and form the very edge that cuts. Yes, it cannot be said that the edge is a completely “imaginary” line, like the horizon - even with good sharpening it will be a surface several microns wide. The main thing is that it should be the same thickness along the entire length of the blade: this means that the thickness of the supply is the same everywhere, which means that cutting with such a knife will be easier and more convenient. For a good cut, compliance with these conditions will be enough. You can understand whether there is an edge on the knife at all and what its condition is by visual assessment. You need to place the knife edge against the light and look at it. A dull edge will reflect along its entire length, while a damaged edge will reflect in several areas. The ideal one will not be visible.

The trick is that the sharper the edge, the smaller its area and the less light it reflects. And the smaller the area of ​​this “imaginary” line (accordingly, the more acute the angles where the leads meet), the easier it is to cut with a knife and the sharper we call it. True, not every angle is suitable for certain types of work - more on this below, in the explanation of why a “too sharp” angle is also bad.

Table for determining the optimal sharpness of a knife according to the Tojiro scale

Here we offer a small but very convenient plate for determining the sharpness of a knife on a seven-point scale. How does it work?

• The highest score is 7. If a knife of a certain category has the correct sharpening angle (that is, the angle at which the leads meet), it receives a 7 on the Tojiro scale.
• If the angle deviates slightly from the norm, up or down, it receives 6 points; deviates more – 5 points, etc.

A logical question arises: are there really “too sharp” knives? Is a sharper angle so bad that it gets a lower score? In general, yes. Firstly, you will spend more time and effort on setting a sharper angle, and not very justifiably. Because, secondly, such an angle will be non-functional. For example, if a hunting knife has a sharpening corresponding to a razor, it will be able, as they say, to cut shavings from a hair, but it will be unsuitable for its intended purpose. If a hunter accidentally hits a bone with an edge, its damage cannot be avoided, and a blade with a nick or chip will become inconvenient to work with. This means that this is the same drawback as a dull edge, which is why a hunting knife that is cut too thin gets only a four on a seven-point scale.

Notes on the table

• Delicate instruments include surgical and shaving instruments; under the fillet knives there are devices for cutting fresh meat or freshly caught fish; all other kitchen knives will be universal; the fourth category will include all knives for everyday use in extreme situations, including combat and tactical ones; knives for heavy work include kukris, machetes and other tools for chopping and planing wood, as well as cleavers for chopping frozen meat and fish.
• Before you begin to determine the degree of sharpening, you need to make sure that the cutting edge is only an “imaginary” line where the leads meet, that is, it is not worn to the point of gouges and chips. If the connections are to be repaired and actually straightened again, it makes no sense to determine the angle between them.
• Particularly “hardcore” tools can still have a vanishing angle of more than forty degrees, but only when working with very hard materials and with sufficient mass of the blade itself.

Hint: in order to sharpen a knife with a symmetrical blade section at the desired degree and get a score of seven points, you should remember that the angle can be half or full. The half angle is the angle at which you hold the blade in relation to the whetstone; The angle formed by the leads will be full (twice as large).
For example, to get a 20-degree lead angle for a tactical knife with symmetrical sharpening, you need to set it twice with different sides at an angle of 10 degrees to the surface on which you are sharpening it.

How do you determine the sharpness of a knife?

Not sugar, hard, pleasure below average, painful, painful, unpleasant, little pleasure Dictionary of Russian synonyms. knife sharp adverb, number of synonyms: 7 painfully (44) ... Synonym dictionary

Inosk: about extremely unpleasant, cutting like a sharp knife Wed. My election by Romanov has hitherto been like a knife... Gr. B. Tolstoy. Tsar Boris. 3. Wed. These words pierced the noblewoman’s heart like a knife. She hit the ground in despair. Gr. A. Tolstoy. Book Silver. 6.… … Michelson's Large Explanatory and Phraseological Dictionary

The knife is sharp- to whom. Razg. Express The same as (that) a knife in the heart of someone, for whom. [Arsinoe:] Do you know, it's a sharp knife for me, When I see how she plays with you! (V. Kurochkin. Misanthrope) ... Phraseological Dictionary of the Russian Literary Language

Knife (sharp) foreigner. about something extremely unpleasant, cutting like a sharp knife. Wed. My election by Romanov has hitherto been like a knife... Gr. A. Tolstoy. Tsar Boris. 3. Wed. These words pierced the noblewoman’s heart like a knife. She hit the ground in despair. Gr. A.… … Michelson's Large Explanatory and Phraseological Dictionary (original spelling)

1. to whom. Razg. About what l.unpleasant, painful for someone l. FSRY, 284; BMS 1998, 407; SFS, 128. 2. what to whom. Razg. Extremely unpleasant, painful, causes mental pain to someone. what l. F 1, 333; Glukhov 1988, 113 ... Large dictionary of Russian sayings

sharp knife- to whom; ... Dictionary of many expressions

The knife is sharp- extremely unpleasant, painful something. FSVChE... Psychology terms

Acute, pungent; sharp and (colloquial) sharp, sharp, acute. 1. Having a thin blade, cutting well, sharpened. Sharp knife. The knife is very sharp. Sharp saber. “It’s a small mouse, but it has a sharp tooth.” Proverb. Sharpen (adv.) a knife. || Tapering towards... ... Ushakov's Explanatory Dictionary

A; m. 1. A cutting tool consisting of a blade and a handle. Table-knife. Penknife. Stab. Slice, cut with a knife. Dull, sharp knife. Finnish knife (short with a wide blade, usually worn in a sheath). Prepare it, put it under the knife... ... encyclopedic Dictionary

KNIFE, knife, husband. A cutting tool consisting of a blade and a handle. Table-knife. Penknife. || The cutting part of different tools. Knife in a meat grinder. ❖ To be at knifepoint with someone (colloquial) to be at enmity. Under the knife (to die; colloquial) to die during... ... Ushakov's Explanatory Dictionary

Books

• A sharp knife for a soft heart
• A sharp knife for a soft heart, Maria Rybakova. A poignant modern novel about the love of a Russian girl, Marina, and a Latino, Ortiz. About love that is beyond the human, because Ortiz is a river. And only by the power of the heroine’s love...

We examined the edge of the blade under a high-magnification microscope. The latest scientific developments were presented at the international mechanical engineering forum.

Incredible invention

The thin blade of the ultra-innovative tool was 10 -9 meters. The world's sharpest knife was intended for cutting small parts for microelectronics. It looks like a needle, the material for which is tungsten.

However, tungsten filament can only cut soft materials. But scientists are working in this direction. The sharpest knife in the world was made using a unique technology. Each element of the blade consists of tungsten atoms, which are filled with nitrogen.

The thickness of the bonding layer turned out to be equal to one atom. This results in an incredibly sharp blade. Carrying out work on the production of tools is low-cost, but the labor intensity of the process does not allow launching mass production of knives.

Does the invention have a future and what are its advantages?

The sharpest knife in the world has undoubted advantages:

• They can even cut microorganisms for study.
• They can perform operations at the cellular level.

An indispensable tool in industry: in the production of medical devices, military technologies, high-quality electronics. It is applicable wherever the highest cutting accuracy is required.

The knife mark is no more than 50 microns. This tool can cut lengthwise the thinnest human hair. Manufacturers note the invention’s resistance to high temperatures. It can be used at 800 degrees Celsius.

An invention for everyday use?

Kramer Knives recently introduced the world's sharpest kitchen knife for sale. The incredibly thin blade thickness is achieved through specially developed technology:

• 6,000 layers of steel are melted from America, Japan and Germany.
• The knife is made at a temperature of 1300 degrees Celsius.
• There is an incandescent stage in saline solution.
• Each product is hand forged.

Became the best among analogues. The blade is sharpened so sharply that the cut layers of food are completely transparent. Professional chefs choose Kramer Knives to make working in the kitchen a pleasure.

When ordering, the cost of a knife varies from hundreds to several thousand dollars. During the manufacturing process, each product acquires a unique pattern on the blade.