What's the Fuller or Blood Groove For in a Knife or Sword?

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[TheModernSurvivalist]

My Books in Amazon:
BITCOIN
My Spanish Channel "SupervivienciaModerna":
Visit My Website:


DISCLAIMER: This post contains Amazon and other affiliate links which means we may receive a small commission at no extra cost to you if you buy something. This of course helps keep the channel going and is much appreciated.

[edi]

With swords, there's even more to it!
You want a certain mass distribution and then on top of it, you have to worry about vibration nodes. If you design a blade poorly, you'll feel a lot more impact on your hand and the blade vibrates like mad and is likely to twist and thus causing poor cuts!

[NewLife-qjmx]

I always understood the purpose was to break suction, therefore easier to pull back out

[Freddy-Da-Freeloadah]

It's called a BLOOD GUTTER!!! That's what they called it in a knife catalog I had back in the 1990s.... IMHO

[VincitOmniaVeritas]

The claim that it leads to air embolism is what really baffles me. If your cut / stab is large enough to allow air to get into the circulatory system, that vessel structure is so far gone that the animal will just bled out way before pulmonary air embolism is a factor.

[mikemcdonald]

its there to drink the blood of your enemies LOL :)

[donhammer]

This is so silly! "EVERYBODY" knows that the grove is for controlling your peas! Think about it, can't stab em, can't slice em so you get "fuller" by using the grove!
Are we going to see you and Matt this afternoon Fernando?

[edi]

I missed one little detail: I-beams are indeed strong, but a flat wedge or diamond crossection cuts far better.
Using broad groves or a spine in the middle can decrease the cutting ability. On the other hand, a very thin blade will get notched and warped pretty fast. Thus, it makes a lot of sense having a flat triangle with a shallow fuller. Now you got a thick and rigid back and more mass close behind the edge, but nothing that gets in the way of the cut.

[ToniaFlorine]

I love knives.. thank you for sharing your knowledge Fernando

[frankmoore]

Yeah! Busse team Gemini .. fits a spec ops 8” sheath perfect . Best blade out there

[paulc]

I have the bayonet at the bottom of the picture with the scabbard with a bobble at the end. I inherited it from an old uncle. Can tell me any history on this rule of bayonet? Thanks..

[williamcraigsartwellejr.]

It's so when you enter the intercoastal cavity you can equalize the pressure to withdraw York a bar or sword that's why we teach you to thrust and twist and retract

[aryafeydakin]

On a blade the size of a knife the term blood groove is even more relevant. On a piece of steel the size of a knife, a fuller will neither lighten the blade (few grams), improve blade angular acceleration (again, insignificant amount), or improve rigidity (if anything, this removal of material is weakening the blade). There is no "i-beaming" a 10 oz piece of steel, this is not a 500 ton construction beam.
The only two things it will do :
1) act as an air admittance
2) reduce suction effect into flesh
That is what the term blood groove is all about.

A blood groove is there firstly to avoid the situation where you let go of the knife/dagger/sword after stabbing up to the grooved part of the blade into the cardio-pulmonary area of the target, and having the knife ending up plugging the wound as well as being sucked in and stuck. When a single wound into the pulmonary area is "plugged" by the blade, the intensity of the pneumothorax is greatly reduced therefore the remaining conscious lifetime of the target greatly increased. Secondly the weapon is less prone to "stick" to the target due to the flesh suction effect by reducing the contact area of the blade with the flesh, creating an air pocket. Meaning it is easier to retrieve the weapon when it is buried deep into a target.

This is not some abstract theory. Let's look at people that still bury swords into living dangerous animal with intention of knocking it down without delay to avoid being themselves injured by the target. Namely the Spanish toreros (bullfighters) and other latin American countries toreros.
Why ? The grooves are not there to make the sword look pretty. On a bull killing sword grooves are not there to lighten the sword. The grooves are not there to make the sword more rigid. The grooves are not there to make the sword accelerate faster during a chopping motion, because this sword _does_ _not_ _cut_. An estoque is totally dull. Absolutely zero cutting motion done with an estoque. So, why are there grooves ? Are there really grooves done to "i-beam" the sword ? Well, absolutely not.
Regarding the grooved bull killing sword, the tradition says :

"Por los canales, se dice, entra en el toro el aire de la muerte, por cada canal un soplo de muerte ; y, por los canales, se dice, del toro escapa su sangre más herida y, con ella, su vida misma"

"Through the grooves, it is said that the air of death enter the bull, through each groove a breath of death ; and, through the grooves, it is said that bull's blood escape faster and with it, its own life"

Indeed, the tradition is right. The bull killing sword (called an estoque) has grooves, not to make it lighter, or stiffer, or more agile. There is no chopping motion, and no swordplay involved but a one-time "surgical" thrust attack. There is a whole art of having the estoque in the "cruz" and in a straight line.
The grooves are there to avoid the sword ending up plugging the wound, and, when the attack is botched, the sword is not in the cruz, is sideway or not totally buried, more chance that it will still knock out the bull. In the case of bullfighting there is the case where a groove-less sword could end up puting the torero in a bad place.
When the bull is extremely large and clever and the bullfighter is overwhelmed by the animal, he can use a "lazy" strike called the golletazo that is a lower thrust to the lung area. When the blade is grooved it unlocks the full potency of this low thrust to the lungs. This strike will instantly knock down the bull because it will create an aggravated pneumotorax due to the groove acting as an air admittance. In mammals, the lungs are packed into a double membrane layer, like a pair of socks into another pair of socks, there is less friction. When the double membrane is damaged, fluid and air start to accumulate into the middle layer, this is called a pneumothorax. At each breath, the blood groove keep the wound open, and air is filling the middle layer, making the lung collapse rapidly asphyxiating the target. But if the blade plugs the wound, then there is no air admittance and the lung collapse way slower.