Off Topic What methodology is acceptable/useful for proof testing of "hard use" marketed knives ?

Cobalt said:
Ok, so what about the infamous spine wack test on a folder. Framelocks use the pressure of my hand to maintain the lock. I habe never had one fail. Then I see people do a spine wack and it fails. Utterly ridiculous. That simulates no use at all. Flame guard on
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In an interview by Blade Magazine (?) (I have a copy somewhere but don't recall the name of the publication and I'm not digging it out just for this) in the 1980s or 90s, Chris Reeve the inventor of the frame lock (initially called the Reeves Integral Lock) stated explicitly that the strength of the frame lock is contributed by the hand on the lock itself [SIC]. The hand also helps to dampen "impact shock" (as opposed to "static shock") which is one frequent cause of lock failure [SIC]. By logical progression, then the spine whack test is invalid on frame locks because it requires removing the hand from the frame lock and holding the knife at the butt end, thus automatically compromising the locks effectiveness and invalidating the spine whack as a valid test.

The spine whack test is more relevant on non-frame locks where the hand on the handle does not contribute to the function of the lock, e.g. the axis lock, back locks, etc. I'm just summarizing something that I still recall being said at a Blade Show & Cutlery Fair (now known as Blade Show) lecture back in the late 80's. Yeah, I'm that old.
 
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Thanks to all responding posters ! :)

I tried to make clear, that I'm interested only in "hard use" proof testing , for those knives that are marketed as such !

Many , probably most, knives clearly do not fit this POU , so do not apply here .

But lots of knives do make such advertising claims or implications . They should live up to their promises , IMO .

Proof testing is not exactly a new or radical practice . So not sure what all the negatively is about .

But please carry on with whatever you want to add . 😊
 
Delgadonine said:
I like watching the crash testing of vehicles. It helps me avoid paying for junk while learning the actual limitations of the models I am interested in.

Hard test reviews of tools isn't a bad idea at all either.
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Crash testing is professionally done so a lot can be learned. But nothing is learned from a semi hitting a stopped honda accord and turns it into a basketball. When destructive testing isn't repeatable there is very little to be gleaned off it. That same truck hits a corolla and it looks much better. So the corolla is stronger? Speed? Weight of truck? Did the corolla owner have brake pedal presed hard or did he release. Same issue for the accord. Lots of variables.
I think that's the point.
 
Doing knife things of increasing intensity until it breaks is just fine with me.

That is, there's no point stabbing a knife into a concrete block because stabbing a concrete block is not a knife task. But sticking a knife tip into a piece of wood (shallow at first and further in for each successive test) is a useful data point for some "hard use knives" since you drilling/prying/digging is a use case for those sorts of knives.

Likewise it makes no sense to baton an engine block with a 4 inch fixed blade, but I would like to see said fix blade run across fresh bone until it's dull.
 
DocJD said:

Just an example of testing . Not about the knife !

I don't know if "vininull" is even still actively testing this way . But really not about him either , in particular .

But is this level, and kind, of testing useful ? Too much, or not enough ?

Are there better examples of such tests / testers ?
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In the old days you would buy a knife that looked cool and felt comfortable to you, take it out in the field and work with it. If it wasn’t sharp enough for you, you would pull out a small stone and work on the edge. Sometimes you would change your technique a little to get the most out of the knife. Occasionally, the knife just wouldn’t feel right or age well, and you would give that to your younger brother and go out and try to find a better knife. That was about all the testing that we needed. Today knives are more numerous and diverse than they ever have been; you can have just about any knife delivered to your mail box within a couple of days. I don’t know why we need to treat every knife purchase as though we were taking it on multi-year polar expedition during the 19th century.

N2s
 
not2sharp said:
In the old days you would buy a knife that looked cool and felt comfortable to you, take it out in the field and work with it. If it wasn’t sharp enough for you, you would pull out a small stone and work on the edge. Sometimes you would change your technique a little to get the most out of the knife. Occasionally, the knife just wouldn’t feel right or age well, and you would give that to your younger brother and go out and try to find a better knife. That was about all the testing that we needed. Today knives are more numerous and diverse than they ever have been; you can have just about any knife delivered to your mail box within a couple of days. I don’t know why we need to treat every knife purchase as though we were taking it on multi-year polar expedition during the 19th century.

N2s
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DocJD said:
Thanks to all responding posters ! :)

I tried to make clear, that I'm interested only in "hard use" proof testing , for those knives that are marketed as such !

Many , probably most, knives clearly do not fit this POU , so do not apply here .

But lots of knives do make such advertising claims or implications . They should live up to their promises , IMO .

Proof testing is not exactly a new or radical practice . So not sure what all the negatively is about .

But please carry on with whatever you want to add . 😊
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The issue I have with ‘testing’ is that there are so many variables and getting repeatable/duplicate tests is difficult. Even something as simple as chopping a 2x4- is the density and grain the same. How hard is someone chopping or battoning? What degree of sharpness, etc?

I do like well made things, so showing a lockblade supporting x amount of weight I find interesting. Pounding the knife blade into hard wood and applying lateral force is dependent on variables.

My favorite folders I would not abuse unless some crazy thing happened, but I did buy a 4 Max Scout simply to check out the knife that held of remarkably to idiotic torture testing by Joe X. It is a beast of a folder.
 
beeinak said:
The issue I have with ‘testing’ is that there are so many variables and getting repeatable/duplicate tests is difficult. Even something as simple as chopping a 2x4- is the density and grain the same. How hard is someone chopping or battoning? What degree of sharpness, etc?

I do like well made things, so showing a lockblade supporting x amount of weight I find interesting. Pounding the knife blade into hard wood and applying lateral force is dependent on variables.
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I agree , ideally at least . The principles of scientific testing should apply .

Variables and subjective elements should be minimized .

Hard to accomplish this without a lot of funding , I'd suppose . 🤷‍♂️
 
DocJD said:

Just an example of testing . Not about the knife !

I don't know if "vininull" is even still actively testing this way . But really not about him either , in particular .

But is this level, and kind, of testing useful ? Too much, or not enough ?

Are there better examples of such tests / testers ?
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It’s far from the most scientific method, but I like what they did with Forged in Fire. They have a sharpness test, strength test, etc. My only gripe with that show is that the strength test (bashing the knife against ice blocks) often comes before the sharpness test. I want to know how well the bladesmith sharpened the edge fresh from the forge, not after you beat the daylights out of it.

The knife design/size should also dictate the kind of hard testing. Kind of like you would test a handgun by firing thousands of rounds, it would be interesting to see a chopper chew through x number of logs.
 
If somebody just wants to use a knife as a letter opener, that's fine. I use knives every day for cutting things, although I don't get many letters anymore. I also use knives for stabbing, prying, reaming, digging, stirring, scraping, and so on. I have had a folder in my hand, about to cut something, when the spine sustained a hard impact from an object weighing about 100 pounds. I am very happy that it did not close on my fingers.

I am glad that various people on Youtube do severe testing of knives. Imperfect data are better than no data.
 
Delgadonine said:
I like watching the crash testing of vehicles. It helps me avoid paying for junk while learning the actual limitations of the models I am interested in.

Hard test reviews of tools isn't a bad idea at all either.
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I watch them so I can choose a vehicle that if I die in a crash it will make me look incredibly gnarly.
 
Grizzly3 said:
It "used to be" that a knife would develop a reputation as being good for this and that. Folks knew not to break a tip or put side pressure on them. They soon realized that "stainless steel" meant junk and at least looked for high carbon stainless steel and knew that carbon steel would rust if not taken proper care of. We bought a knife and used it for years and sometimes decades. Now, there is a whole entertainment industry that has sprung up. The world is led by "experts" who should probably just get a real job that produces something or helps someone. How hard is it to figure out that you need a different design for different tasks and then to treat your knife with a certain amount of care? Oh well, it's a different world now. Enjoy.
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I don’t remember writing this yet here it is;)

Well said Sir.
 
Back in the 80's: a couple of us hit an anvil with what I think was freon...
Even it couldn't survive a sledgehammer attack!
Breaking things does not impress me.
 
I recently had a discussion about real world hard use testing for a knife. The other person and I could only think of a few situations where in the real world I’d use a knife over other tools. Taking the head off a fish this could be rather abusive depending on the knife. Opening a coconut although I don’t have real world experience here. Lastly processing dried bamboo due to the hardness and more abrasive quality of bamboo. These were some common tests I think would be valid. I’ve also had axes and knives take on damage from fatwood which can be quite hard.

Some of these abuse/destruction tests are entertaining and interesting but without data such as steel, HRC, sharpening angle, and thickness behind the edge the tests are pretty much useless.

Without that data hamming a knife through a bolt could be or could not be impressive.
 
Oh boy! I have Opinions about this subject!

I admit, I've skimmed the thread, so some of this may have been addressed. Since nobody has been able to find a "proper" standard, it's safe to assume one does not exist.

So, what would scienticious testing need to do?

For folding knives, we're mostly interested in lock failure, I suppose.

Prior to testing, all of the physical properties of the blade should be known, obviously.

1) Known and repeatable grip strength.

2) Knife being held the same distance from the lock interface.

3) Edge-strike tests, from blade-on to 20 degrees of deflection on either side. Repeat until failure, or a known, "acceptable" number of ft/lbs. There is data about how hard people can hit things with other things, but most likely, people would want to know exactly how much it takes to break the blade, or the lock.

4) Strain tests, slowly increasing the weight on the blade, at a known and repeatable speed. It should be done with the edge up, and the edge down.

5) Side-loading tests. Same as 3 and 4, with the flat side of the blade taking the shock and the weight, at some repeatable distance from the lock interface, with the handle being clamped and the blade unsupported. If the lock is asymmetrical (framelocks and linerlocks for example), then testing should be done from both sides.

6) Leverage testing. Essentially the same as 5, except that now the point of the blade is driven a constant distance into a material with known qualities, and the handle is unsupported. The results may not be any different from 5, but somebody is going to say "you did it wrong!" because "hard use" includes prying.

7) Reverse shock-load test. The usual nonsense of giving the spine a sharp whack to show that the lock can (or can't) hold up to being asked to do the exact opposite of it's job. It needs to have a technical sounding name, because we're doing science. Keep all the other distances and forces constant while increasing striking force at a constant rate, and so on and so forth.

8) Somebody too much time and money who's willing to fund the purchase and programming of a robot to do this.

9) Somebody who's willing to put on a lab coat and safety glasses, then narrate the testing process with just the right mix of knowing what they're doing, and not taking the whole thing too seriously.
 
The other issue here is, what do you, or in general, is considered proper use or abuse.

So if you test a knife for uses that it was meant to do and it fails, that's bad. The problem is there is a difference of opinion in what is normal use.

1. Is a spine wack failure enough for a company to replace your knife? I doubt it
2. If the lock fails when stabbed into a harder object with a proper hold, that's is a fail. However, like in liner locks, was the lock fully engaged?

3. On large hard use fixed blades, Is chopping 100% agreed upon to be normal use? most would agree. What about chopping through cow bones, or other animals?
4. Is batoning considered 100% normal use.? does batoning into solid dense wood and knots matter? I would say a hard use knife should be able to do both.

5. Lateral bending. This is more a reflection of blade geometry than anything else. If you take a thin dagger style blade and stick into wood over an inch deep and bend, you are likely to end up with a shorter knife. Not meant for that use. Can you test that to know the limits? sure. Shouldn't the maker be doing that for you? why should you break your knife, and test for him.
Conversely a hard use knife with a thick tip should pass any lateral test. Hard use knife with a thinner profile may not. Ontarios Marine Raider Bowie is a fairly tough knife. It has a very thin tip. If you stick that tip into a log over an inch deep and pry, you will likely bend it. An Ontario Tanto with it's thicker tip should have no issue.

But again, should not the manufacturers be doing these tests and putting out a standard that their product adheres to? We should know the limits of a manufacturers knife before we buy it. But we rarely do.
 
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