Aggressive Testing of Knives and the negative attitudes towards it...

Marion David Poff

Marion David Poff

Joined
Oct 8, 1998
Messages
5,403
Good Day,

I have noticed a negative attitude on the part of some makers and manufacturers concerning scientific destructive testing.

Even some afficiandos cast an angry eye in the direction of destructive testing.

I do not understand this.

Scientific destructive testing is an extremely valuable service, it tests knives to their limits, it discerns the truth and lies in marketing claims, it quantifies the values of materials.

All of the information that emerges benefits us. This information assists us in making decisions about where we want to spend our dollar for maximum effectiveness and return on our investment. It assists makers and manufacturers in creating a better product.

I wonder if the negative attitudes spring from a mindset that believes that ignorance is bliss, or from a mindset that fears loss of revenue more than low integrity products.

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Thank you,
Marion David Poff aka Eye, Cd'A ID, USA mdpoff@hotmail.com

Talonite and Cobalt Materials Resource Page

"We will either find a way, or make one." Hannibal, 210 B.C.
 
Marion, I think you'll find it is possible to diasgree without having a sinister motive, as in:
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I wonder if the negative attitudes spring from a mindset that believes that ignorance is bliss, or from a mindset that fears loss of revenue more than low integrity products.
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The simple fact that something fails is not necessarily informative without a clear understanding of exactly why it failed. What is the precise structural deficiency that caused it to fail, and is that deficiency at issue in the blade's intended use? Are other design issues more important?

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Scientific destructive testing is an extremely valuable service, it tests knives to their limits, it discerns the truth and lies in marketing claims, it quantifies the values of materials.
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Maybe



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Jerry Hossom
www.hossom.com
 
I feel that destructive testing is usefull, but to be honest, when I put my heart and soul into making a knife it hurts to destroy it. And so I am not overly fond of destructive testing and will drag my heels when the time arrives.
I would just as soon have someone else do it. Kinda like getting someone else to put down your favorite dog.(which by the way I would do myself....some things you just cant ask someone else to do)

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There is no such thing as "good enough", either your work is good or it is not. How is your work?
SGT BLADES www.therockies.com/hagar/
 
"Destructive" (at least somewhat) testing is the only way to really test.

I followed "gun testing" in some magazines, well there was NEVER a winner. It was always: S&W is excellent, but a little tuning... in contrast C@£t is just as good, if you don't mind a little tuning... not to forget R#!%r, which is almost as fine, even before tuning...
So nobody was ever hurt, beside the reader who did NEVER get any real information.

So let's start with a definition of cutting power. E.g.
Cutting in a machine which uses the "full" length of the blade, at a defined load, measure the cutting resistance of a normalized "target good" and count cuts to double cutting resistance.
That's ONE result.
Or how many standard cuts to go 1" deep.
That's another result.
There are many others to think of.

Bending in a vise is not so wise at all, even if standart in certain exclusive circles...

Do this test ONLY with knives that have been sharpened according a standardized method. So you do compare apples with apples.
Good luck.
mad.gif



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D.T. UTZINGER
 
I think that destructive testing has its place with knives, but it has to be done right. And it needs to be done in a way that tests the knifes ability to be used for its intended purpose. If you want to see how much you can flex the blade in a big knife that might be flexed at some point, thats fine. Or if you want to make the lock on a folder fail thats fine to, but do it in a way that you can show exactly how much force it took to make it fail. And show how the force was applied to the knife. Things like that are great and give you good information about knives. Destructive testing bothers me when peolpe do things like putting a pipe over the handle of a knife thats in a vice and prying it until it breaks.Then saying it was really easy to do, but not giving any information on how much force wwas applied or how it was applied. You can't really call it a test if all you do is break it and not learn anything from it. You can find a way to break any knife no matter how strong, but that doesn't matter much if it doesn't tell you anything about the knife.

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Fix it right the first time, use Baling Wire !
 
Marion :

[destructive blade evaluation]

All of the information that emerges benefits us. This information assists us in making decisions about where we want to spend our dollar for maximum effectiveness and return on our investment. It assists makers and manufacturers in creating a better product.
Click to expand...

It also prevents hype which is very scary to those people selling inferior products. Anyway, as for method in general, if you work with a blade and do not damage it in some way you cannot in any way make a meaningful comparision. For example I can take a 440A blade and a 440C blade and cut 10' of 1/8" ridged cardboard. Niether blade is effected. This provides a limited amount of information - both can cut the 10' without functionally blunting - but in no way enables you to judge the relative performance of the two as both pass at 100 %.

If you want to make some kind of meaningful statement about the merit of two blades then at least one of them has to be overstressed. If both of them are then so much the better. For the simple cardboard test, you keep cutting until both are unable to pass a given criteria. From the two lengths of cardboard cut you can now compare the two steels assuming the geometries are identical. If not then you normalize those properties first.

The only issue that restricts what I do is blade replacement, ie. what is covered. All use is destructive, what is important is that the damage be inline with the stress, if it is then it should not be covered, if it isn't then it should - simple. For example, I soaked a #7 Basic in salt water and saw rust - this was expected. If however the handle fell off I would be returning it for a replacement (if I had bought it anyway).

As for what it says about the maker, look to the quality of their goods. There is a direct correlation between that and their resistance to having their blades evaluated.

-Cliff
 
There is nothing wrong with destructive testing. It is a good thing. I don't make claims about how strong my knives are, but, time and experienced have proven that they are strong enough for their intended purpose. If I was to make claims, I would have test data to back them up. I general, knives are so hard (highly stressed) that they start behaving a little strangely when destroyed. You can see that by noting how carefully tests that demonstrate strength are conducted.
I am much more interested in cutting-that is what knives are made to do. Honestly, I am always able to produce minor dings, dents and flat spots on any knife if I cut certain materials long enough, in the right way. This is the nature of a knife's edge-a hard material sharpened to an acute angle.
Work it hard enough, and long enough and it's going to be altered. This will happen with every material, at any hardness and heat treat. Accept it. It's why knives have to be sharpened eventually.
Remember, that while you're using the knife, making it get dull, that there are so many things happening-ergonomics, cutting performance, fatigue on you, etc. that are also important. If a knife hurts your hand after 5 cuts, it's useless even if it can make another 50 cuts, right?
So, I guess I'm just saying that perspective is always a good thing. How many of you use your knives that hard, anyway?

RJ Martin
 
I think, as has been mentioned by others, that "destructive" knife testing, as it exists, is too subjective to provide a definitive conclusion concerning the true quality of the products. It would be improved by standardization, with each knife getting the exact same treatment. This would mean the elimination of the subconscious biases of the tester. If I happen to prefer a certain brand, or individual knife, I might unintentionally try a little harder to get it to perform. If I have a machine that applies equal effort to each product and measures the result in standard units, and have standard cutting materials, then I have something quantitative to compare. Measured, repeatable, standardized tests, along with the subjective input from someone actually using the knife in it's intended role would give us the best of both. The end result could be that the subjective quality of the knife would nullify some tested deficiency. The manufacturers would also benefit from the results. Just Don't ask me about who is going to pay for all of this neat technology. We do still learn quite a bit from the methods we use, so if someone wants to demolish their knife for our benefit I'll be happy to read their reports.

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Dave
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If at first you don't succeed, go buy a knife.
 
Hello,


Most of the knives that become the focus of destructive testing showdowns are those made by manufacurers who claim their knives are tough (Cold Steel, Fallkniven, Mad Dog, etc.). While not all of them appreciate the methods used in various third party tests, it can be said that they "asked for it" by their claims.

In contrast, I have never seen and probably will never see the destructive testing of knives that are sold as knives, and not some kind of indestructable wonder.

It breaks down to which niche a knife fits in, and that niche is chosen by the marketing chosen by the manufacturer. As such, destructive testing is quite useful to filter out the truth from the hype.




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-Gregory Zolas
tinsta@hotmail.com
 
Marion,
I took your advice. I placed one of my Model 4 folders on a stump and hit it as hard as I could with a 20 pound sledge hammer. It broke pretty bad.

Now I'll have to put that in my brochure and other literature - "Don't lay on a stump and hit with a big ole hammer".

What did I prove? That sure was a big hammer.

I won't tell you who's order it was, but he sure will be mad, I imagine.

Just kidding.......I agree with RJ.
 
This is a great thread with lots of good content. (Jeez, I got to drop by more often!) I believe destructive testing can be good and bad. It depends on many factors that are obvious though. I destroyed 4 blades on Tuesday, a D-2 at 60 Rc, a differentially tempered A-2 with an Rc 60 edge, a 420-V blade, and one made of the exotic alloy Tantung. I learned a lot doing it. But the stresses I put these blades through were much more than the blades would ever see if they were finished knives. Sorta like Kit's 20 lb hammer test. (I like that one Kit!)
smile.gif


RJ has summed it up pretty well in my opinion.



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www.simonichknives.com
 
Just my little 2 cents worth, but doesn't destructive testing give data that may not be otherwise obtainable. The average consummer will not want to do this and not every knife is designed for this, but I think that destructive testing has it's place in say a survival knife. If the knife is advertised as tough, then it better measure up!
 
Did you ever stop and think hmmm,why do they crash all those nice NEW cars into block walls?


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Jay
Life is like a box of chocolates,never know what your gona git!
 
Gentlemen,

Perspective is important, noting the likely stress a knife will see and interpreting the data in light of those conditions.

And remember, I am speaking of scientific testing here, not deciding to break a knife, and sending it into the sun.

I am speaking of incremental, measured, repeatable, documented, organized testing.

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Thank you,
Marion David Poff aka Eye, Cd'A ID, USA mdpoff@hotmail.com

Talonite and Cobalt Materials Resource Page

"We will either find a way, or make one." Hannibal, 210 B.C.
 
Marion, I do chopping, flexing the edge over a brass rod, and sometimes just carry and use a knife for lots of cutting. I have destroyed a few that were not salvegable and I have bent one. That one was for the performance test of the ABS Journeyman Smith rating. It cut the knotty pine 2x4 twice, easily shaved the hair from the arm using the same area as was used for the chopping, and then cut the 1" free hanging rope about 6" from the end. It was then dulled and I bent it just past 90 degrees. There is a pic of the blade and the rope on page 2 of my web site. The knife has an OAL of about 15" with 10" from the handle to the tip. Without the help of Charlie Oches and James Bateson, I doubt if I would have been able to make the steel perform as it did.
I have at a time earlier in my knife making career, failed the bend test, and didn't know why. That is one reason that it is good to find out the limits of your products and make sure that they reach the limit.
Testing without learning is a waste of time and serves no useful purpose. If you can learn something, I say go for it.


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Ray Kirk
http://www.tah-usa.net/raker
 
Raker :

It was then dulled and I bent it just past 90 degrees.
Click to expand...

It is common for this to be able to be done without a bar on the knife? Does that make a difference to how the knife is judged?

-Cliff
 
certainly way down on the list....but one reason they crash all those cars into walls is because they can AFFORD to. RJ said it all, breaking a knife proves nothing. Scientific brings up a lot of interesting questions...the foremost in my mind is having an atomic microscope to check the stuff out before and after.....cutting rope and newspaper with your bare hands and writing down the results is not much of a scientific test in my humble opinion.

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http://www.mayoknives.com




[This message has been edited by tom mayo (edited 03-12-2000).]
 
"RJ said it all, breaking a knife proves nothing. "

So in other words, destructive testing is worthless. I guess gun manufacturers don't perform destructive tests on guns do they. Glock and H&K do and I'd bet that most others do to.

Cars are crashed for the heck of it! or maybe it's to see if the new safety features measure up. Like weakened stress points that direct the force of impact away from the occupants.

The G-shock watch, hmmm. You think someone might have destroyed it with just a few too many G's over at Casio. I'd bet money on it.

Precision/critical aircraft parts. As part of quality control, a number in every batch is destroyed to assure structural integrity. I know this for fact since I was involved in it.

Car Batteries. Overload them on purpose to see if they pop? Some companies use to. I was at one that did. It was fun watching the tops blow off the batteries.

The list goes on.

Hey does Sal Glesser test the locks on his knives? I thought he posted a very long time ago that he did. Since this is from a fading memory, I can't say for sure.

I'm sure that it is understood that a 1/8 inch thick blade is going to snap. I think most people interested in destructive testing are talking about large blades with incredible claims or maybe locking mechanisms that are reputed to take so much more force than the average lock.

This is my take on it, and a very small opinion from someone who knows absolutely nothing about knife making. However, I know a bit about some of the other industries I mentioned, so there you go. I myself am Glad Cliff tested the Mad Dog, Cold Steel, Ontario, H.I. knives as well as so many others. This showed how far you can go with the product you are going to buy. In the case of some of these knives, not very far. The most bang for your Buck.
 
I see very little value in destructive testing.To me it is like watching crash up derby:it is pretty fun to watch,Im glad it isn't my car(knife)and in the end there is really not too much real measureable scientific data to be had from it.Still,it is pretty neat to watch and read about,and I have been entertained by the whole process.Until the methods are completely standardized,they will always be too subjective to be useful to me.
troy
 
The great thing about not doing destructive testing is that it leaves you free to claim anything you want about your product. I make the strongest this, the toughest that, blah, blah, blah. I wonder how many sales were lost when knives that were not suppose to break, Broke. hmmm. I can name several orders that I would have cancelled had their knives not measured up to the claims. But if you don't care, then don't read the results and continue thinking what you like be it right, wrong, but mostly unknown.
 
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