Does a Fuller on a knife make it Fully stronger than an UnFullerfilled knife?

R

Roguer

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Jan 5, 2015
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OK newbie grade question time!

Some one was telling me my Ka-Bar 1211 was "Stronger" because of the (I'll call it the Fuller and not the "BLOOD GROOVE" some one insisted on calling it) Fuller gives the I-Beam extra strength vs, my OKC 499M non fuller blade. (its a great beater blade and tough as heck, some one wanted it to Mod it down to some weird shape because it has all that steel to play with, the non sharpened swedge lets me take it out where I live like the Ka-bars I got). Yes I know alloys make them slightly different critters.

From what I understandishly know, is the Fuller fulfills the act of strengthening out the blade as its thinned out to make it lighter and use less material while keeping the performance of a thicker heavier blade...sort ofishly. It all made me wonder again what is more rightishly along those lines.

I figured the experted people here can explain it better than I can think it.

Thanks in advance for answering this newbie grade question.
 
It doesn’t make the knife stronger it makes it lighter, with minimal strength loss.

If you add a fuller to a knife it has a better weight to strength ratio than it did before the fuller.

Its a moot point anyway. Everyone knows its a blood groove to break the vacuum. Making it easier to withdraw the knife. 😂
 
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Figured it was a mixed mash of those combos.

Thanks!

Now a Blood Groove with a Fuller would make it a vacuum tacti-coolio breaker and a stronger knife making it even greater tacti-coolio! Right? 🤔
🤯
 
That is only part of the answer. If you compare an"I-Beam" cross section beam vs a beam with the same cross sectional areabut a plain rectangle or square cross section shape, and thus the same weight per length; The I beam is 'stronger'. And the biggest increase in strength is in the axis through the center web of the I shape, not at 90 degrees to it..
 
Removing mass, unless it's in some unusual and very specific locations where a design has introduced stress concentrations, does not increase the strength of a beam but in fact does the opposite.

I-beams do have better strength and stiffness per unit mass than solid beams, at least in the case of vertical loads along the web of the beam (not side to side, crucially). This matters when you're forging a sword from a given mass of steel and comparing fullered and non-fullered designs, as the fullered sword can be made larger and longer for the same weight and still be stiff/strong enough to survive a strike on target without flexing or breaking. It does not help you when weight isn't a concern, like when you're grinding a fuller into a pocket knife blade.

Edited for clarity
 
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marrenmiller said:
Removing mass, unless it's [...] where a design has introduced stress concentrations, does not increase [...] strength
Click to expand...

in fact, it reduces absolute strength. So,

eveled said:
If you add a fuller to a knife it has a better weight to strength ratio than it did before the fuller
Click to expand...

but lower absolute strength. And that, as far as I know, succinctly summarizes the physics of fullers on blades.
 
As already stated above , makes it lighter with minimal loss of strength .:cool:

But only absolutely stronger at equivalent weight .

The other stuff about suction/ sticking in wounds is mostly BS , IMO . ;)
 
And yet...

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Roman swords usually did not contain blood runnels. Suffice it to say that after stabbing your opponent, you would need to sharply twist the sword to withdraw it, thus making it available for the next enemy who just stepped into line.

UPDATE 4/27/22: See discussion in comments which explain the ‘blood runnel’ is not actually a thing. The fuller in a sword (the groove) exists to reduce weight of the blade without loss of strength. A lighter blade means faster movement. Would also result in less physical drain from swinging a several pound weapon.

Above from : https://ancientfinances.com/2019/04/08/gladius-sword-used-by-roman-legionnaires/

Roman gladius was an industrial strength killing tool that built and helped maintain an empire that spanned the known world .
 
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David Mary said:
And yet...

View attachment 1973557
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Those are different. Those were first seen on French Foreign Legion fighting knives. The french call them Grantons.

Gran means speed (like granprix). Ton means dot. So in English “speed dots” Speed dots make for faster slashing cuts.
By reducing drag as the blade moves through the air.

We were talking about blood grooves not speed dots.
 
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eveled said:
Those are different. Those were first seen on French Foreign Legion fighting knives. The french call them Grantons.

Gran means speed (like granprix). Ton means dot. So in English “speed dots” Speed dots make for faster slashing cuts.
By reducing drag as the blade moves through the air.

We were talking about blood grooves not speed dots.
Click to expand...
Consistent with the Jerry Lewis Cult ! 🤪
 
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