Edge retention in a SD blade

Shing

Shing

Joined
Feb 2, 2003
Messages
2,261
Hopefully, having to use a knife for SD happens a few times in ones' lifetime and for most of us never. So my contention is edge holding in a blade designed and carried soley for SD is a minor factor in choosing ones' SD knife.

I think what matters in a SD knife is carriability and concealment, speed of deployment, effectiveness in stabbing, slashing and parrying and toughness. Edge retention is a fairly minor consideration because the number of cuts and stabbs it has to contend with would be very small and even in practice cutting, its not going to cut everyday.

If it was to come up against armour like chain mail or trauma plates, then, maybe a harder edge would be needed.

So I think the steels used and the HT given to make the blades for fighters hard should instead focus on making them tough and springy. This would lead to most people having to carry 2 or more knives, a tough bladed fighter with limited edge holding and a knife with a harder and more brittle blade for no SD use.
 
If that's what you think, you should have put this in Practical Tactical.

In many or most jurisdictions in the US and I'm sure in the UK, carrying a knife for self-defense is not considered a legitimate purpose. While no court should contend that a knife carried for ordinary utility, in the normal course of work or recreation, can never be used for self-defense, courts generally frown on a dedicated fighting knife. It smacks of premeditation. (That's the evil twin of "planning ahead".)

Further, a knife carried solely for self-defense, with another knife carried for utility, will not impress itself on muscle memory the way the frequently used utility knife will. So when the emergency strikes, you are much more likely to reach for that utility knife -- you might, if dressed lightly, not even have the self-defense knife with you.

The first principle of self-defense is not to be there. Avoid trouble and the places it most often occurs. Prepare yourself for it anyway with training and alertness. Provide yourself with experience in using found objects defensively. And get yourself a good utility knife that has defensive capabilities.

The secret to successful use of a knife in self-defense is not to use it in a fight. There are no Marquis of Cutlery rules. The first time your opponent should see it is when you are pulling it out of his ribcage. (Fighting fair is foolish.)
 
If some were to use a knife for SD, God forbid, I think a good lesson would be to study what the avaridge street thug uses. I live just to the north of Washington D.C. and in the city there are some serious crime issues.

One of the most rapidly gaining popularity weapons is the sliding blade utility knife. Fast, cheap and diposable, and inflicts serious slash wounds.

Another popular weapon is a cheap butcher knife. Again no joke. They kill people every day.

I think a dedicated SD knife should be something light, fast, and something you will ditch down the next sewer opening you pass.

Better yet-carry pepper spray and a good walking stick and you will go far.
 
Shing said:
If it was to come up against armour like chain mail or trauma plates, then, maybe a harder edge would be needed.
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Is this a goof or are you seriously considering the possibility of facing off against someone in Chain Mail in a knife fight? :rolleyes:
 
I assume Shing's point is that we are very unlikely to encounter somebody wearing chain mail (outside of a rennaisance festival) so edge hardness need not be tailored for hardness. I tend to agree. One of the reason that I thin my edges so much is that years ago my slash tests showed that thin cut a lot deeper with less effort. I figured that I might only get in one quick surprise slash before getting overrun. I wanted that one slash to be incapacitating even if it was not perfectly executed.
 
Good point, Jeff. That means a knife like an Endura -- which is a great utility EDC -- would also do the job for SD.
 
I think Shing is right on the money that a pure SD blade doesn't need the extra edge retention ability of a utility or EDC type knife. A prime example is Ka-bars use of AUS-8 in their TDI knife. I also agree with Esav In that most people are best served using a utility/EDC piece for defense vs. a specialized blade, however how do you get around the fact that a utility/EDC such as a folder isn't very practical to deploy in a SD situation? Deploying a folder under stress, being beaten on, or engaged in a FUT (borrowing a Southnarc term:F-cked Up Tangle) is very difficult when compared to accessing a small purpose driven fixed blade. Opinions?
 
Jeff Clark said:
My slash tests also showed that the best blade shapes had a wide backswept belly like a skinner. I wouldn't rate the Endura has a particularly effective SD design. A Browning folding skinner would slash a lot better:
http://www.browning.com/products/catalog/knives/detail.asp?value=007G&cat_id=322&type_id=7090
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interesting. its been my experience that blades with pronounced bellies cut much better - and smoother - than straight edges, hawkbills, etc. this is why i routinely choose skinner style knives, or drop points. however, the 'self defense gurus' always tout hawkbill-type knives as the best for slashing - especially those such as the spyderco civilian, matriarch, etc which were primarily designed for last ditch escape slashing.

so which is it? :)

never having slashed a human being (thank god) i would guess that a skinner style knife would leave a clean slash while something hooked like the civilian would leave a ragged gash. however, if the person is wearing a leather coat or heavy clothing i would honestly put my money on the skinner/drop point slash penetrating it quite smoothly, while the hawkbill just raked across the surface with a *lot* of resistance.
 
Lobo103 said:
[...]however how do you get around the fact that a utility/EDC such as a folder isn't very practical to deploy in a SD situation? Deploying a folder under stress, being beaten on, or engaged in a FUT (borrowing a Southnarc term:F-cked Up Tangle) is very difficult when compared to accessing a small purpose driven fixed blade. Opinions?
Click to expand...

I agree absolutely. A folder won't be nearly as easy to deal with as something you can just pull from a sheath. In fact if you look at the Army's manual on bayonet and knife fighting, they do not emphasize precise movements, but rather their "instinctive" system. Opening a folder would only hinder your ability to defend yourself. It requires a pretty deliberate set of motions to remember when you're in a life-or-death situation.

If you must carry a folder for this purpose, you should be extremely familiar with it.
 
Another thing to keep in mind here is that a slash w/ a small blade (by this I mean a concealable defensive piece...not a Kukri) isn't going to be very effective at incapacitating a determined aggressor and chances are you are not going to be able to maintain the range to execute a slash for very long if at all. Real world conflict has forward momentum...it's not dualing at range as some "experts" would have you believe. If you've ever seen or participated in a fist fight at school/bar/work etc you know it doesn't look much like a boxing match. The same holds true for a "knife fight", there probably won't be proportional armament (another Snarc term), and there will be a lot of forward momentum in close quarters. A series of hard, deep, stabs is going to be your best bet, not only because the situation will probably limit just about everything else, but also because the anatomy dictates that this will more quickly and effectively achieve "shut-down" of the opponent.
 
With a short blade a stab isn't all that effective. A 2 inch deep, 12 inch wide slash is very achievable with a short skinning knife. If it is a horizontal slash across the lower abdomen the fight is over.

The problem with the hawkbill knives is that you can snag them on things like buckles or zippers and lose them.
 
Esav Benyamin said:
\

The secret to successful use of a knife in self-defense is not to use it in a fight. There are no Marquis of Cutlery rules. The first time your opponent should see it is when you are pulling it out of his ribcage. (Fighting fair is foolish.)
Click to expand...

LOL, reminds me of a Terry Pratchett passage, paraphrased here...

The Marquis of Queensbury rules originated with the Marquis of Queensbury, who was somewhat more physically challenged than many of his compatriots, and frequently lost boxing matches held for sport with his peers. He then developed the Marquis of Queensbury rules, which was essentially a long list of the many places you weren't allowed to hit him. This worked perfectly well, as long as his opponents had read his rules. The Marquis's boxing improved somewhat with the introduction of his rules, but he was unfortunately beaten and killed when he was leaving a back alley at night and ran into a disadvantaged and literacy-challenged young man who had not had the good fortune of reading his rules, but was nonetheless rather proficient with a piece of brick in a wool sock... ever since then, fighters who abide by the Marquis's rules have been frequently known to mutter "Damn the bloody Marquis!" in the bloody ground they are usually sprawled over...
 
Jeff- If you look at the effect of multiple wound channels each about 3" to 3.5" deep that is pretty signifigant. If your using an edge up method your also getting additional tissue damage at the edge slices and tears upward...thats a fairly nasty wound. My other issue with your theory is how do expect to have room to execute a broad slash? Most attacks are predicated on the fact that you've already been caught unaware and are in extreme close quarters w/ your aggressor. I'm not saying that a slash is something you should take out of your toolbox but I am saying that you shouldn't put all of your eggs in that basket. Again, just my opinion. Excellent discussion so far. :D
 
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