Bending or Breaking?

R

Ralf

Joined
Oct 11, 1998
Messages
565
After reading this article from MadDog http://www.mdenterprise.com/combat_k.htm I was surprised to find that a knife should rather break than bend after applying an excess of lateral force. I always thought a bend blade is better than a broken one, since you might be able to straighten it out again. Especially a sword would be next to useless in cqc when it's broken and therefore shorter. Kevin mentions the Samurai, who according to him preferred broken sword over bend ones. I highly doubt this fact. Not only have I read articles stating exactly the opposite, but using common sense I come to the same conclusion that a bend blade is not useless, especially if it’s a sword. A set of swords (wakizashi + katana) was of high value in those days. Getting a new one not only took time, it was also expensive. A bend blade on the other hand could simply be straightened out by a halfway skilled blacksmith. You wouldn't need a sword maker for that.

Sure, I see the point that a broken long sword can make a nice short sword but a bend long sword can become a straight long sword again, and a valuable asset in any medieval battle. I bet those guys didn’t give much about aesthetics, as long as a tool got the job done. If you can kill someone with a bend blade, you still kill him. Going with a broken blade in combat for sure meant a big disadvantage. Kevin also mentions that the blade wouldn’t fit in its sheath anymore. This argument is valid only for hard sheaths. Sheaths in the old days were mostly made of leather (ok, I know the ones for Samurai swords are made of wood) and could easily accomplish a bend blade.

So what’s your opinion: To Bend or to Break?
 
I have wondered about this also, for some time. I was always of the opinion that a bent blade was better than a broken one. I will say that Kevin makes a good point about a broken blade still being able to be used since it is straight.

My only concern is that you cannot decide were the blade is going to break and, thus, if it breaks at or near the handle it is next to useless. I think that I would still go with a bent blade myself, because of that reason, if I had a choice.
 
I agree. Concerning where the blade breaks, if a blade breaks an inch from the handle you have the option of holding the handle and using a 1" stub or trying to hold the rest of the blade to use it. Ouch.

If it bends in the same place (or any place) you still have a handle, you still have a tip, you still have the entire length of the blade.

I hate to say this, because I lust after Mad Dog knives, but I do wonder whether Mad Dog wasn't expressing his own personal philosophy (evidenced by his super-hard and ceramic knives) rather than hard fact. I don't mean this as an insult; it's only natural. But you do have to consider it when you read ANY expert opinion.
 
If a blade bends, you will have a weak spot there that will bend again without as much effort as the time before. If my sword bends in the heat of the moment, how deftly am I apt to wield it?

A broken sword will still retain the strength through what is left and, due to its lesser weight can moved about faster with less effort. Yes, you give up reach but, you have more speed.

Personally, if I'm out in the boonies, I won't have a blacksmith with me to fix my bent blade. I might bash it with a rock or log and get in semi-straight again but, good luck getting it back into the Kydex sheath I am apt to have. Mad Dog's comments are valid when kept in context. If I new my bent blade was going back to the maker or other qualified individual for a fix AND I did not need at the time it became unserviceable then, sure a bent blade could possibly be restored but with what confindence? Whether my knife breaks or bends, its junk then and there, hopefully I can manage my way back to civilazation and procure a better knife for my next adventure.

Sid
 
Note when Hilton Yam tested the prototype Mad Dog pATAK in 3/16"

http://www.knifeforums.com/ubb/Forum4/HTML/000079.html

the tip of the blade took a perm. bend, it didn't snap off. He then straightened it up by prying on wood. This would not have been possible obviously if the tip had broken off.

I would *much* prefer a bend, besides the fact that I should be able to restore it, there are safety issues. A broken blade can send pieces of metal flying and it could as well throw you off balance, both likely to cause injury.

-Cliff

[This message has been edited by Cliff Stamp (edited 26 March 1999).]
 
If you could decide were the knife is going to break, like say near the tip or more than halfway between the handle and tip I might say that a knife could still be effective.

But, you cannot say were the failure is going to occur, and, assuming murphy's law, it will break at the worst possible location, the HANDLE/BLADE juncture. I guess if you have an entire roll of duct tape, you can make a handle out of the base of the blade, of course you would be dead by then and you would end up with a blade that is uselessly short.

 
OK, speaking as someone that has both bent AND broken blades (several, and bent, then broke, the same blade on one knife....yeah, I never learn), I would much prefer a bent blade.

Am I the only one on this forum that can speak with experience? You guys mean that no one else on here has broken a blade, then wished that it was only bent (I have). Yeah, sure, it was ONLY a locking folder. But I sure wished I had left it bent!

O_D
 
There are many examples of Nihonto ('Japanese Samauri Swords') which have been shortened. Some were probably shortened when the switch from tachi to the shorter katana took place, but many were shortened due to tip breakage.

There is even a classification of faults in Nihonto blades, and what the preferred method of repair is. None of these faults involve bent blades.

Remember that a fine wootz blade could be bent a very great amount, but would either spring back to original shape, or break, if stressed beyond its' limit of elasticity.

For a survival knife, it must be able to pry; if it bends doing that, you are in deep kim chee. A survival knife is a sharpened pry bar. Remember the joint Russian-USA trip to the North Pole; the expedition turned into a fiasco when the Russian military tents ripped apart. Everyone had a knife, and started digging snow caves. Because of the extreme cold, only one knife was functional at the end. A Mad Dog ATAK.

Put me in the 'break rather than bend column, please.'
 
The point about a bend putting a weak spot in the blade is well put, but I would still rather have a blade that may break or bend in the future than one which has already broken.

Walt, if it bends when you pry, you may find the Kim Chee deep and steaming. But if it snaps in two doing the same thing, will the KC stink any less? I don't think so.
And yes, I get it, the ATAK is strong. Fine. But the knife in your story neither broke nor bent, so how is that relevant? Yes, a knife that neither breaks nor bends, but simply takes all the punishment you can give and laughs in your face, is the ideal. But we're talking about which is the lesser of two evils. If you can afford a Mad Dog which will neither break nor bend without a forklift, good for you. That's obviously the best solution.


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This is a rather odd topic for debate as bend or break, both suck about equally. The ideal is a knife blade that will be hard enough at the edge to offer great edge holding and tough enough at the spine to deflect without deforming, and as strong (generally resistant to deflecting at all) as possible. The variables in the formula are steel, blade shape, and heat-treating. I'll go with the maker who gets the best combination of toughness, strength, edge holding, and sharpness. I want the knife with the most extreme limits of performance, and don't much care whether it breaks or bends when it goes beyond them. I would much rather have a knife that breaks at 2000 pounds than the one that bends at 1000, and visa-versa.

I would rather have half a straight sword than one that was bent 90 degrees in the middle, but I would rather have a bent sword if the bend was only a few degrees. If surviving in the wilderness, I would rather have two 6" straight edges than a single 12" bent one. This issue seems firmly in the grey area to me.

I tell you this though, if Mad Dog were so inclined, he could provide a very strong and detailed argument for the position he took, whether all who read it agreed or not.
 
This is a controversial question, but I think the controversy is mostly due to a misunderstanding. My own feeling is I would prefer the blade that can take the most force before failing, regardless of how it fails, and that means it'll break. A blade with an annealed spine bends quite easily, and though you may be able to straighten it once without it breaking, even several times if you're lucky, you definitely can't keep doing that forever.

A blade with a spring tempered spine takes much more force before it even begins to flex, and then it springs back as soon as the force is removed. It can only be broken by flexing it so far a blade with an annealed spine would have been bent into a pretzel long before.

So, the reason spring temper is superior is not that it fails by breaking -- that's incidental. Its superiority is in taking far more lateral force before failure. You can see for yourself without destroying any expensive knives by comparing a flat spring to a piece of annealed steel of similar dimensions. You can bend 1/4" annealed steel easily. You will have great difficulty breaking a 1/4" flat spring.

The worst blades are those that break without bending or flexing first, without any warning. Stainless steels are notorious for that. Any steel can do that if there's a flaw in the steel.

-Cougar Allen :{)
 
Excellent response, Cougar.

The first time I ever read McClung's diatribe on why his knives are superior I was darned tempted to frame the whole "bend vs. break" argument in terms of what I know not of fighting knives, but of kitchen kniives. Then I got to thinking about what he might really be trying to say in terms of latent strength. I think you've done an excellent job of bringing up that topic. I wish that he'd expressed himself more in terms of latent strengths and stored energy because I think that the whole "bend vs. break" dialogue largely misses the issue.

mps
 
appologies for the double post. If I knew how to stop or fix this doubling I would do so. ..... Help?...
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mps

[This message has been edited by mps (edited 26 March 1999).]
 
Steve, I think you said it perfectly. What is that called.......compromise? Yes. Snap it early, no good, bend it early no good, somewere in the middle is were we all want to be, I assume.

Oh, and why was damascus so popular, hmmm, could it be because it would not break?
 
The same applies to other tools designed to take lateral force like wrenches and crowbars. You never see an ad displaying a wrench that's bent into uselessness with the proud claim that it bent 90 degrees without breaking -- why are some knives advertised like that??? I think Mad Dog was probably more or less in rant mode when he wrote that article -- those ads make me see red, too. You can put a permanent bend in cheap junk tools like the useless toy lug wrenches that come with the car but you cannot bend a good tool. It's very difficult to break a good tool but if you put a pipe on it for leverage and test it to failure it will always break before taking any noticeable permanent bend.

Whenever I see a bent wrench or crowbar or knife I see that as proof it's junk. When I see a bent knife in an ad I don't know whether to laugh or cry or pound my head against a tree.

-Cougar Allen :{)
 
ralf
they bent in battle!! i,d like to see what hes been reading.
i like springy back hard edge
harley

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Cougar, that was a lot of help. Thanks.

You're right, I thought MD was just saying that if two knives can take, say, 350 lbs of lateral force, but one breaks at 350 and the other bends at 350, then the one that broke performed better. Thanks again.
 
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