Krovostok or still dol? Let's figure it out. Dole on a knife, or the terrible truth behind knives with "blood flow" Why do we need valleys on a knife blade
Have you ever wondered why such a longitudinal recess is made on the blade of a knife? And it is found on knives quite often. Yes, it's bloodthirsty! - you say. And you will be slightly wrong. There is absolutely no wash in such bloodletting. Hunters confirm that if you stick such a knife into the carcass of an animal, then only a few drops of blood will run out. The purpose of this groove on the knife is a little different, but we will call it correctly - dol . So…
The longitudinal recess on the knife blade can be made on one or both sides.
Dol (dola) - a chute, a longitudinal recess on the blade of cold steel. The Germans call it - "hohlkehle", and the British - "fuller".
What is the dol on the blade of a knife for?
- When it is necessary to reduce the weight of the blade (for example, a fuller on a saber reduces its weight by up to 30 percent);
- Reducing the friction surface;
- Aesthetics, fashion, tradition: the use of grooves on the blade can also be justified from an aesthetic point of view; agree that a knife with fullers on the blade looks much more interesting;
- With the help of a dol, you can correct the balance of the knife;
The blade of the Bekas knife has a thickness of 2.4 mm, however, valleys are made on its surface on both sides to reduce the friction surface. - But not to increase the rigidity of the blade (more on that below).
Dol - call it right!
In the company of cutlers, call this part of the knife gutter, valley, hohlkehle, fuller or simply deepening, but try not to use the concepts of "blood flow, blood flow". Well, in order to completely show off erudition, for reference I cite the following information:
- the word "dol" is borrowed from a common Slavic root dol, those. pit, lowland;
- there is a dol not only on a knife, but also, for example, on a turret;
- was first seen on the blades of cold weapons of the Bronze Age (I wonder, at that time, for what purpose was the dol on the weapon?).
By the way, the use of a gutter on short-bladed knives (up to 9 cm) is nothing more than decoration and does not make any sense.
Fuller on the blade for rigidity. Is it so?
Well, now a little sopromat. To be honest, for some time I thought that the fuller on the blade brings him some rigidity. But I received a response from our buyer, who mathematically proved that this was not the case. Calculations Viktor Belyaev, below:
Without going into the wilds of strength of materials, I will try to explain why the dol does not increase but reduces the stiffness of the blade.
Hardness and rigidity are different concepts. Hardness is the resistance of a material to the penetration of a harder body into it. Rigidity is the ability of elements to resist deformation.
Hardness depends on the material (various steels, hardening, work hardening, etc.) and is determined by various methods: Rockwell, Vickers, etc.
Rigidity depends on the bearing capacity of the material, on the shape of the element, design, loading scheme, etc.
For example, let's say that a knife with fullers is an I-beam No. 10 GOST 8239-79, without fullers - a solid bar with a section like that of an I-beam 100x55 mm (10x5.5 cm), their length and material are the same. They are fixed at one end, forces are applied to the other, respectively. Rd- to the two-beam, Rb- to the beam.
Bending moment M=P*l kg*cm, where P kg-force, l cm shoulder is the distance from the anchorage to the point of application of forces. Also, from the sopromat M=g*w kg*cm, where g-kg/cm sq. - allowable stress in the material from the action of force, w cm \ 3 (centimeter to the third power) - section modulus.
W \u003d b * h square (cm \ 3). Equating, we get for an I-beam Rd * l \u003d g*w d; for timber Pb*l=g*wb. Dividing the second equation by the first and canceling equal values, we get: Pb / Pd = Wb / Wd, those. the maximum force applied to the beam will be as many times greater than the maximum force applied to the I-beam, how many times the moment of resistance of the beam is greater than the moment of resistance of the I-beam.
Wb \u003d b * hkv / 6 \u003d 10 * 5.5 \ 2 / 6 \u003d 50.4 cm \ 3; according to the assortment, the moment of resistance Wy of the I-beam No. 10 \u003d 6.49 cm \ 3. 50,4\6,49=7,7.
Accordingly, the allowable force applied to the beam will be 7.7 times greater than the force applied to the I-beam.
For blades with a solid section and fuller, this ratio will be much less due to a slight decrease in the cross-sectional area, but less!
Speaking about the purpose of the valley, many people argue that it is done to increase the rigidity of the blade - this is absolutely wrong. So can say those who did not know the sopromat. Reducing the cross-sectional area in the manufacture of fuller without increasing the thickness and (or) width of the blade leads to a decrease in the moment of resistance W and, consequently, a decrease in stiffness. I think: a dol is a reduction in weight, a decrease in the friction surface, aesthetics, a tribute to fashion, a tradition, even a bloodstream - if you are used to saying so, but not to increase rigidity.
Anyone willing to argue? Write in the comments. And about others, we'll talk next time.
Review article “Krovostok or still dol? Let's figure it out" prepared by the online store
Krovostok or still dol? Let's figure it out!
On Santoku knives, some manufacturers make oval recesses on the blades closer to the cutting edge, the so-called "air pockets".
Many people ask why and why they are needed? About everything in order.
Santoku is a versatile Japanese kitchen knife. It was originally developed as a modification of a Western (particularly French) chef's knife for cutting beef, and then it was adapted to the needs of Japanese cuisine.
"Santoku" literally translates as "three good things" or "three uses", which refers to the suitability of the knife to cut, chop and chop well. The size of the santoku is convenient for cutting into small slices or cubes of both meat and vegetables. Compared to the Japanese original, Western santoku models have a different balance, blade design, and are made of softer steel, which affects the thickness of the blade and edge.
Also, European variations of santoku can have pockets on the blade (they are also called "grantons"), designed to reduce food sticking to the knife (cheese, boiled sausage, etc.)
"Bloodstone" on a knife- the topic is extremely popular, and in almost all conversations regarding knives conducted on various forums, the age-old question pops up: "What is knives with blood, and, so to speak, why bloodstream do you need this one?"
This fundamentally erroneous term, as is known, means a special groove on the knife, or rather on his blade. But be prepared for the fact that for the mention of the word "blood" on serious knife forums you will be beaten (maybe even kicked), because it is correct and correct to call this thing on the blade - "dol". And "bloodstock" is vulgar jargon, unworthy of a knaifer's speech, and all that. Nevertheless, even at fairly serious knife forums, a variety of versions are being circulated about why this dol on a knife. That's what we're talking about today...
From the point of view of the layman, a knife with a "blood flow" is a strictly obligatory attribute of a frightening combat ghoul like John Rambo's cutter - thanks to Hollywood. In fact, this is not at all the case.
Dales on the blade: "hunting" version
The first version (or rather, a group of versions under the general name "hunting") regarding why we need valleys on the blade, says that supposedly groove on the blade remained a legacy from the hunting knives of the Middle Ages. Like, if you leave a knife in the body, then "blood flows down the bloodstream" from the carcass of the animal. In other words, hence the name itself, and the theory of application: knives with blood serve to bleed the victim.
Only representatives of the office plankton of large metropolitan areas can fall for such a myth. Any person who in one way or another was related to the countryside and subsistence farming knows perfectly well that in order to quickly bleed the carcass, you just need to hang it upside down and cut the cervical blood vessels. And on a knife left in a carcass, a lot of blood will not flow out through a narrow groove.
The same applies to the alternative version of the hunting version about "blood drain on the hunt": it seems like if the knife remains in the body of a runaway animal after a blow, then the success of the event depends on where exactly this blow was struck. Nonsense, because if, say, the heart, spleen, liver or other organs of increased blood supply are affected, then, regardless of the presence of dol on the knife, the animal will weaken from massive internal bleeding. And if you stick a knife into the muscle of a sufficiently large animal, then the animal will gallop away, and you will no longer see your knife, if there are at least as many gutters as you like. An insufficiently large wounded animal, of course, will weaken under the weight of the knife, but I strongly doubt that the groove on the knife was specially introduced into the design of the blades for catching hares with bare hands. Be that as it may, it is to the hunting versions that we owe the appearance of the name "bloodblood on the knife", and it is precisely because of their delusional that this word is so much disliked by knife experts. But let's move on to other myths.
Blood flow on a knife: the theory, God forgive me, of "bodily vacuum"
The next version of the appointment of the valley appeals to physics, telling us about the "body vacuum" shrouded in mystery. It is mysterious for the simple reason that few of the adherents of this version themselves know what it is. Often, on near-knife forums, one can stumble upon statements that the valleys on the blade are intended (I quote): "to let air out of the body so that the knife does not jam under pressure." I confess that in surgical practice I have come across "exit of air from the body", for example, in the case of fecal peritonitis, gggg. however, such a situation does not imply any clamping of a knife in a wound. More experienced knifers present a slightly modified version: they say that the groove on the blade allegedly serves to improve the reverse process, namely, to allow air to enter the body. It seems that in this way the internal vacuum of the body is violated, and the knife is not sucked into the wound due to the closing of the edges of the wound. At first glance - a plausible version, but ... Well, the cavities of the human body are in no way capable of "sucking to death" - not a compressor for that. In addition, it will be no more difficult to remove the knife than to plunge it in, since the blade will simply cut its way back, even if the closed tissues stubbornly resist.
Some unique people firmly believe that the dol-chute on the knife serves to conduct air into the body, but not at all to make it easier to remove it later, but only to infect the wound with "outboard" air that enters through the channel, the walls of which are flesh and the surface of the valley itself.
There is also a mixed version: they say that the notorious vacuum is created in the wound around the blade, and the blood flowing through the “blood stream” eliminates it, which makes it easier to remove the blade from the victim’s body.
Dole on a knife: "technical" versions
There are purely technological options. For example, a groove on a knife reduces the overall weight. Of course, the "minus-fabric" - makes it easier. And through holes make it even easier. Why is everything stuck in these grooves? Or that the dol not only makes it easier, but also changes the balance of the knife. Again twenty-five: the classic fuller goes along the entire length of the blade, that is, it facilitates evenly throughout the entire length. It is much easier and more effective to change the balance in other ways.
There are other options about simplifying the forging process in the presence of a fuller: supposedly the cutting edge of the knife during hardening heats up faster than the butt (the blunt thick part), and the fuller somehow evens out this imbalance.
Why bloodthirst? But for beauty!
There is also a bantering version that dol is done purely for beauty. And you know, lately the aesthetic function of the valley has really become quite real: since public opinion recognized the "blood on the knife" as a licking attribute of a "real cool combat blade" (tm), individual manufacturers began to sculpt it wherever they hit with the sole purpose: please the consumer.
So what is a "dagger on a knife" really, and what purpose does it serve?
In fact, everything is simple. Dol really appeared on the blades a very long time ago - back in the early Middle Ages, if not earlier. And its main purpose was and remains to increase the strength and hardness of the blade.
Everything is elementary: in this case, the principle of the so-called I-beam (aka double-T, aka I-beam, aka H-shaped) is used - a well-known old engineering technique in architecture. The name comes from the Latin "taurus" - bull. The cut profile of such a beam vaguely resembles bull horns connected together.
"I-beam is a standard profile of structural elements made of black rolled metal or wood, resembling the letter "H" in cross-section. An I-beam is about 7 times stronger and 30 times stiffer than a square profile beam of the same cross-sectional area." (c) Wikipedia. It is these steel I-beams, by the way, that are used in the process of skyscraper construction as a frame base.
In other words, metal of the same mass and total cross-sectional area, but cast in the form of an I-beam, is much stronger in bending than a monolithic one. To be convinced of this, it is enough to conduct an experiment: try to bend a monolithic strip of metal a few millimeters thick. With a high degree of probability, with effort or pressure with your weight, you will bend the strip into an arc. If you try to do the same with a metal profile of the same thickness, but made in the form of a "corner" - you are guaranteed to fail. Let the engineers correct me: the number of axes of the structure increases, due to which the strength increases.
Of course, the cut of the blade with a fuller does not fully correspond to the classic profile of an I-beam, so the figures for the increase in rigidity and strength are more than 30 times inferior to it. Nevertheless, the fact remains: a blade with a fuller in the design along the entire length of the fuller is stronger and tougher than a blade of the same mass and shape without a fuller.
There is one but: the longer the "product", the more noticeable the effect of the I-profile, and therefore the valley. That is, on swords, checkers, sabers, long daggers and bayonets, the dol is vital to increase the bending strength of the blade ...
Here, for example, is a German bayonet of the 1898/1905 model:
Vale on the sword:
Dol on a dagger:
But the dol on some short-bladed knife with a bevel under the "real hunting" (tm) looks like a pure decoration, because what for it is needed there.
But in general, some kind of shaped perversion, as for me: two valleys on one side of the blade.
Such are the things. So forget about
provocative
knife myths
Hello, friends! We continue our theme of knife myths. This article is a logical continuation of the article "", so if anyone is not familiar yet, start with it. The topic is really quite broad, so it can not fit in one part.
By the way, I would like to take this opportunity to inform all my readers about an excellent store offering excellent handmade knives at affordable prices and delivery throughout Russia (I want to buy such a knife). Well, now back to our topic today.
So, let's begin.
Myth #1.
The longitudinal notch on the blade of the knife is the “blood flow”.
This is a fundamentally wrong concept. According to (), paragraph 6, subparagraph 6.1.1.5.1, the term "bloodstream" is an unacceptable term for use as a synonym for the term "dol". Dol- this is a longitudinal recess on the blade.
Dol A clear example of reducing the weight of a knife due to the dol 
Dole on a knife
And here it is not necessary to start ranting about what can be called one way or another, the main thing is that it is clear to everyone. And in general, that bloodstream" is a common term. Remember, the term bloodstream" And " dol are two different concepts and should not be linked.
The second myth is a continuation of the first.
Myth #2.
If the knife has a "bleed", then such a knife is a melee weapon.
Initially, there was an opinion that the presence of bloodstream» on a knife increases bleeding if the knife is left in the wound after being hit. But, apart from fiction and an attempt to pass off the wishful thinking as real, there is nothing more in this opinion.
Here, the real "Krovostok" and its leader "Shilo"
Once again - this longitudinal recess - " dol”, and it serves, first of all, to lighten the weight of the blade and balance it, as well as to strengthen the entire structure.
And, moreover, it is impossible to judge about any transfer of a knife to the category of edged weapons, due to the presence of a fuller on the blade. There is also this only thing that will give the product such a proud name. Therefore, this is not even a myth, but rather nonsense and ignorance of regulatory documents.
Myth #3.
A sure sign of edged weapons is an anatomical handle.
It is important to understand what an anatomical handle is. It can be either an ordinary handle, which has special sub-finger recesses, or a handle custom-made according to a cast of a hand and exactly repeating its shape. Custom-made handles are an extremely rare phenomenon and have nothing to do with the concept cold weapons.
Myth number 4.
In the Russian Federation, knives with one-handed opening are prohibited.
Any adherent of this opinion will send you straight to, with shouts - “Here, look, everything is written here - it’s impossible!”
You can refer to the article “What knives are prohibited in Russia” for details, and in short, knives with automatic, inertial opening and the “butterfly” type with a blade length are prohibited. over 90 mm.
Butterfly knife Automatic knife Folding knife
No other products are mentioned. Thus, the vast majority of folding knives with flippers, hooks, pins and other things have never been banned by anyone.
Myth number 5.
If there is a lanyard on the knife, then you cannot carry such a knife with you.
No matter how crazy it may sound, but such an opinion is still present. Of course, additional questions from law enforcement officers may arise, but in general, the presence of a lanyard does not affect the involvement of a knife in melee weapons. To help you, the same article, where nothing is said about.
Leather lanyard
These are far from all the myths on the knife theme, but that's enough for today. Leave your controversial questions about knives in the comments, and I will try to answer them. That's all, put likes and subscribe to our news and updates.
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