Is it bloody or is it still a valley? Let's figure it out. Fuller on a knife, or the terrible truth behind knives with "blood" Why are fullers on a knife blade needed?
Have you ever wondered why such a longitudinal depression is made on the blade of a knife? And it is found on knives quite often. Yes, this is a bloodstream! - you say. And you will be a little wrong. There is absolutely no point in such bloodletting. Hunters confirm that if you stick such a knife into the carcass of an animal, only a few drops of blood will run out. The purpose of this groove on the knife is slightly different, but we will call it correctly - dol . So…
A longitudinal recess on the knife blade can be made on either one or both sides.
Dol (dola) - a groove, a longitudinal depression on the blade of a bladed weapon. The Germans call it “hohlkehle”, and the British call it “fuller”.
Why is a fuller made on a knife blade?
- 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, a tribute to fashion, tradition: the use of indentations on the blade can be justified from an aesthetic point of view; agree that a knife with fullers on the blade looks much more interesting;
- Using the dol you can correct the balancing of the knife;
The blade of the Bekas knife has a thickness of 2.4 mm, however, its surface has fullers on both sides to reduce the friction surface. - But not to increase the rigidity of the blade (more on that below).
Dol - call it correctly!
In a company of knife makers, call this part of the knife gutter, valley, hohlkehle, fuller or simply deepening, but try not to use the concept of “blood flow, blood flow”. Well, in order to really show off my erudition, for reference I provide the following information:
- the word "dol" is borrowed from a common Slavic root dol, those. hole, lowland;
- There is a dol not only on the knife, but also, for example, on the revolver drum;
- was first noticed on the blades of bladed weapons of the Bronze Age (I wonder, at that time, what was the purpose of making a fuller on a weapon?).
By the way, the use of a groove on short-bladed knives (up to 9 cm) is nothing more than decoration and makes no sense.
Full on the blade for rigidity. Is it so?
Well, now a little evidence. I admit honestly, for some time I thought that the fuller on the blade adds some rigidity to it. But I received a response from our buyer, who mathematically proved that this is not so. Calculations Viktor Belyaev, I quote below:
Without going into the jungle of strength of materials, I will try to explain why the fuller does not increase but decreases the rigidity of the blade.
Hardness and rigidity are different concepts. Hardness is the resistance of a material to the penetration of more solid. Stiffness is the ability of elements to resist deformation.
Hardness depends on the material (various steels, hardening, hardening, etc.) and is determined by various methods: Rockwell, Vickers, etc.
Hardness depends on bearing capacity material, element shape, structure, loading pattern, etc.
For example, let’s say that a knife with fullers is an I-beam No. 10 GOST 8239-79, without fullers it is a solid block with a cross-section like an I-beam 100x55 mm (10x5.5 cm), their length and material are the same. They are fixed at one end and forces are applied to the other, respectively. Rd- to the I-beam, RB- to the beam.
Bending moment M=P*l kg*cm, where P kg-force l cm shoulder - distance from fastening to the point of application of forces. Also, from evidence M=g*w kg*cm, where g-kg/cm sq. - permissible stress in the material due to force, w cm\3 (centimeter to the third power) - section moment of resistance.
W= b*h sq (cm\3). Equating, we get for the I-beam Рд*l = 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 as the moment of resistance of the beam more torque I-beam resistance.
Wb = b*hkv/6 = 10*5.5\2/6 =50.4 cm\3; according to the assortment, the moment of resistance Wy of I-beam No. 10 = 6.49 cm\3. 50,4\6,49=7,7.
Accordingly, the permissible force applied to the beam will be 7.7 times greater than the force applied to the I-beam.
For blades with a solid cross-section and with a fuller, this ratio will be significantly less due to a slight decrease in the cross-sectional area, but less!
Speaking about the purpose of the fuller, many people claim that it is done to increase the rigidity of the blade - this is absolutely wrong. This is what those who don’t know the evidence can say. Reducing the cross-sectional area when making a fuller without increasing the thickness and (or) width of the blade leads to a decrease in the moment of resistance W and, accordingly, a decrease in rigidity. I believe: duty is a reduction in weight, a reduction in the friction surface, aesthetics, a tribute to fashion, tradition, even blood flow - if you are used to saying so, but not to increase rigidity.
Anyone want to argue? Write in the comments. And about others, we’ll talk next time.
Review article “Krovostok or still a valley? Let’s figure it out” prepared by the online store
Is it bloody or is it still a valley? Let's figure it out!
On Santoku knives, some manufacturers make oval notches on the blades closer to the cutting edge, so-called “air pockets”.
Many people ask why and what are they needed for? First things first.
Santoku is a universal Japanese kitchen knife. It was originally developed as a modification of the Western (specifically French) chef's knife for cutting beef, and then it was adapted for the needs of Japanese cuisine.
"Santoku" literally translates to "three good things" or "three uses", which refers to the knife's ability to cut, chop and chop well. The size of the santoku is convenient for cutting into small slices or cubes both meat and vegetables. Compared to the Japanese original, Western Santoku models have different balancing, blade design, and are made of softer steel, which affects the thickness of the blade and edge.
Also, European variations of santoku may have pockets on the blade (they are also called “grantons”), designed to reduce the sticking of food to the knife (cooked raw sausage, etc.)
"Krovostok" on a knife- the topic is extremely popular, and in almost all conversations regarding knives, conducted on a variety of forums, the eternal question comes up: “What is knives with blood flow, and, frankly speaking, why blood flow Is this the one you need?"
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 mentioning the word “bloodstock” on serious knife forums you will be beaten (maybe even kicked), since it is correct and correct to call this thing on the blade “dol”. And “krovostok” is vulgar jargon, unworthy of the speech of a kniffer, and all that. Nevertheless, even on fairly serious knife forums, a variety of versions are exaggerated about why this is actually needed. dol on the knife. That's what we'll talk about today...
From the point of view of the average person, a knife with a “blood cap” is a strictly required attribute of a terrifying fighting beast like director John Rambo - thanks to Hollywood. In fact, this is not true at all.
Fullers on the blade: "hunting" version
The first version (or rather, a group of versions under common name"hunting") regarding why they are needed fullers on the blade, says that supposedly this blade groove left as an inheritance from hunting knives Middle Ages. Like, if you leave a knife in the body, “blood flows down the bloodstream” from the animal’s carcass. In other words, hence both the name and the theory of application: knives with "blood" serve to bleed the victim.
Only representatives of the office plankton of large cities can fall for such a myth. Any person who in one way or another had anything to do with rural areas and subsistence farming, knows perfectly well that to quickly bleed a carcass, you simply need to hang it upside down and cut the neck blood vessels. But a knife left in a carcass will not leak much blood through a narrow groove.
The same goes for alternative option hunting version about “blood drainage during a hunt”: it seems like if a knife after a blow remains in the body of a runaway animal, 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 the blade on the knife, the animal will weaken from massive internal bleeding. And if you stick a knife into the muscle of a large enough animal, the animal will gallop away, and you will no longer see your knife, even if there are any number of gutters there. A wounded animal that is not large enough will, of course, weaken under the weight of the knife, but I strongly doubt that the groove on the knife was specifically 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 “blood on a knife,” and it is precisely because of their delusional nature that knife experts dislike this word so much. But let's move on to other myths.
Blood on a knife: the theory, God forgive me, of “bodily vacuum”
The next version of the purpose of the valley appeals to physics, telling us about a “bodily 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 knife forums you can come across statements that the fullers on the blade are intended (I quote): “to allow air to escape from the body, so that the knife does not jam under pressure.” I confess that in surgical practice I have encountered “air leaving the body,” for example, in the case of fecal peritonitis, yyyy. True, such a situation does not imply any clamping of the knife in the wound. More experienced knifesmiths present a slightly modified version: they say that the groove on the blade supposedly serves to improve the reverse process, namely, the penetration of air into the body. It seems that in this way the internal vacuum of the body is broken, and the knife is not sucked into the wound due to the closing of the edges of the wound. At first glance, this is a plausible version, but... Well, cavities are in no way capable of human body“suck in to death” is not a compressor. In addition, removing the knife will be no more difficult than inserting it, since the blade will simply cut its way back, even if the closed tissues stubbornly resist.
Some unique people firmly believe that the groove on the knife serves to conduct air into the body, but not at all to make it easier to remove later, but only to infect the wound with “outboard” air entering 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 “bloodstream” eliminates it, which makes it easier to remove the blade from the victim’s body.
Shoulder on a knife: “technical” versions
There are purely technological options. For example, a groove on a knife reduces total weight. Of course, “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 balancing of the knife. Twenty-five again: the classic fuller runs along the entire length of the blade, that is, it lightens evenly along its entire length. It is much easier and more effective to change the balance in other ways.
There are also options for simplifying the forging process if there is a fuller: supposedly cutting edge When hardening, the knife heats up faster than the butt (the blunt thick part), and the blade somehow evens out this imbalance.
Why blood flow? And for beauty!
There is also a banter version that the dol is done purely for beauty. And you know, in Lately the aesthetic function of the valley actually becomes quite real: since public opinion recognized “blood on a knife” as a lickable attribute of a “real cool fighting blade” (tm), some manufacturers began to sculpt it everywhere with the sole purpose of pleasing the consumer.
So what is a “dollar on a knife” really, and what purposes does it serve?
It's actually simple. Dol actually appeared on blades a long time ago - back in the days early Middle Ages, if not sooner. 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 is used (aka double-T, aka I-beam, aka H-shaped) - a well-known ancient 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.
“An I-beam is a standard profile of structural elements made of ferrous rolled steel or wood, in cross-section resembling the shape of the letter “H”. An I-beam is approximately 7 times stronger and 30 times stiffer than a square profile beam of the same cross-sectional area.” (c) Wikipedia. It is precisely 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 shape of an I-beam, is much stronger in bending than monolithic. To verify this, it is enough to conduct an experiment: try to bend a monolithic strip of metal several millimeters thick. With a high degree of probability, by applying effort or pressing 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 shape 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 the fuller does not fully correspond to the classic I-beam profile, 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 stiffer than a blade without a fuller of similar weight and shape.
There is one thing: the longer the “product”, the more noticeable the effect of the I-beam profile, and therefore the fuller. That is, on swords, checkers, sabers, long daggers and bayonets, the fuller is vital to increase the bending strength of the blade...
Here, for example, is a German bayonet of the 1898/1905 model:
Full on the sword:
Dole on the dagger:
But the dol on some short-bladed knife with a “real hunting knife” (tm) angle looks like pure decoration, because why is it needed there.
But in general there is some kind of formal perversion, as for me: two fullers on one side of the blade.
Such are the things. So forget about it already
provocative
knife myths
Hello, friends! We continue our topic about 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 cannot be fit into 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 reasonable prices and delivery throughout Russia (I want to buy such a knife). Well, now let's get back to our topic today.
So, let's begin.
Myth No. 1.
A longitudinal notch on a knife blade is a “blood hole.”
This is a fundamentally wrong concept. According to (), clause 6, subclause 6.1.1.5.1, the term “krovostok” is an unacceptable synonym for the term “dol”. Dol- This is a longitudinal notch on the blade.
Fuller A clear example of reducing the weight of a knife due to the fuller 
Dol on a knife
And here there is no need to start ranting on the topic of 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 noun. 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 No. 2.
If a knife has a “bleed”, then such a knife is a bladed weapon.
Initially, there was an opinion that the presence of “ blood flow"on a knife increases bleeding if you leave the knife in the wound after a blow. But, apart from fiction and an attempt to pass off wishful thinking as reality, there is nothing more to this opinion.
Here is the real “Krovostok” and its leader “Shiloh”
Once again - this longitudinal notch - “ 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 any transfer of a knife to the category of edged weapons, due to the presence of a fuller on the blade. There is, and this is the 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 No. 3.
A sure sign of a bladed weapon is an anatomical handle.
What is important here is an understanding of what an anatomical handle is. This can be either a regular handle, which has special finger grooves, or a custom-made handle based on a cast of the hand and exactly repeating its shape. Individually made handles are an extremely rare phenomenon and have nothing to do with the concept edged weapons.
Myth No. 4.
IN Russian Federation knives with one-handed opening are prohibited.
Any adherent of this opinion will send you straight to, shouting - “Look, everything is written here - you can’t!”
You can refer to the article “Which 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 more than 90 mm.
Butterfly knife Automatic knife Folding knife
We are not talking about any other products. Thus, the vast majority of folding knives with flippers, hooks, pins, etc., have never been banned.
Myth No. 5.
If a knife has a lanyard, then you cannot carry such a knife with you.
No matter how crazy it may sound, such an opinion still exists. Of course, additional questions may arise from law enforcement officers, but in general, the presence of a lanyard does not in any way affect the involvement of the knife as a bladed weapon. To help you, the same article, which says nothing about it.
Leather lanyard Lanyards-keychains Lanyard on a knife
These are far from all the myths on knife topics, but that’s enough for today. Leave yours in the comments controversial issues about knives, and I will try to answer them. That's all, like and subscribe to our news and updates.
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