standardized knife tests - why not?

[MickMan]

I think scientific tests can provide valuable info that makes all hype less effective, and hidden (conveniently ommited) facts exposed. Also, people would be less interested where the knives were made, and by whom. Knife experts could perform these tests in a lab setting, under identical conditions for different knives. The things that would need testing could easily be quantified and presented in a nice table. No hype, favoritism or bias. Some of the things I would like to see tested:

- how much force is needed to crack the lock (on a folder) in different directions (up, down, sideways) and at various points on the length of the blade.
- tip strength (use a machine to make sure equal force is applied every time)
- slashing/thrusting in a medium
-corrosion resistance (like saltwater immersion for example)..

These were just off the top of my head and I am sure there could be more. The reason I thought about this is because too many times knife reviews (especially on the forums) are written from a biased (although well-meaning) viewpoint and cover info that may have little meaning for others.

[This message has been edited by MickMan (edited 03-30-2000).]

 

[SDouglas]

While it is certainly possible and perhaps even desirable to develop Standard Tests for certain qualities other equally important qualities do not lend themselves to empirical testing.

How do you empirically measure Fit and Finish or Balance or aesthetics?

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AKTI Member No. A000370

 

[Will York]

I think Mick has some good points. Perhaps at some point the forums, or some of its members and/or moderators, could begin developing a standardized approach to testing. There's a lot of creative, technically adept talent here. As long as the tests made sense in terms of actually measuring what they set out to measure, and in quantifiable, replicatable form, I could see where such testing could be very valuable. For instance, the tests might be viewed as an extension and broadening of the ABS journeyman and master smith testing protocols.
Cliff Stamp, for one, has been developing some methodology which seems to hold a lot of promise for standardized testing. He refines and re-evaluates his testing methods on a regular basis, to try to arrive at meaningful sampling techniques that result in consistent, fair and accurate data. As a physicist, perhaps he could be called upon to evaluate and suggest methods.
Maybe we're not there yet, but I wouldn't be surprised to see some form of testing emerge soon, for setting benchmarks across the spectrum of new alloys we've been inundated with over the past year. Between the CPM steels, INFI, and the hard-facing alloys, as applied via the talents of a profusion of creative and talented knifemakers, we seem to cross a new threshhold of performance every few months--sometimes weeks.
Open mindedness, civility, and a commitment to include as many points of view as possible might just make such a venture very rewarding. I can't think of any losers in such a quest, unless it would be those who chose to ignore the knowledge gained thereby.
Good ideas, MickMan.

 

[Cliff Stamp]

Will :

[referring to me]

He refines and re-evaluates his testing methods on a regular basis, to try to arrive at meaningful sampling techniques that result in consistent, fair and accurate data.

This is very necessary. It is possible to have a method work very well on one blade and not on another as the blade materials might behave radically differently. This is why to get a meaningful rating, you must not only do something to quantify its performance but you must be sure of what is controlling the abilities that you are rating. Otherwise you could very well collect a very misleading set of data.

One thing that I would suggest is first for those wanting to create a "standard testing method" is to do some work yourself. Unless you experience it firsthand you can easily end up making very unreasonable suggestions which at best will simply not be constructive.

I can't think of any losers in such a quest, unless it would be those who chose to ignore the knowledge gained thereby.

Pretty much, there is a direct correlation between the quality of someone's goods and their resistance to having them evaluated.

-Cliff

 

[Will York]

Cliff--Your words:

"It is possible to have a method work very well on one blade and not on another as the blade materials might behave radically differently. This is why to get a meaningful rating, you must not only do something to quantify its performance but you must be sure of what is controlling the abilities that you are rating. Otherwise you could very well collect a very misleading set of data."

Given your progress in devising tests to date, do you think it's possible to set up a protocol that would fairly test performance of any blade in a way that would make it fairly measurable against any other? For example, your "string pressure" and "number of cuts through fabric" tests--do you see eventually reaching a point where an index could be arrived at that would fairly rank any blade in terms of sharpness, aggressiveness, and edge retention, based on these tests?
--Will

 

[cerulean]

It's very difficult, if not completely impossible, to create a set of standardized tests for knives. There's just too much variation from knife to knife. You can say that knife A keeps an edge longer than knife B, but it's hard to say why. There are so many variables you have to deal with; steel type, grind type, blade length, edge angle, sharpening technique, heat treat, etc. You can theoretically account for all of these variables, but that's going to be hard to do in the real world.

I think this is what Cliff Stamp was getting at when he said,

It is possible to have a method work very well on one blade and not on another as the blade materials might behave radically differently. This is why to get a meaningful rating, you must not only do something to quantify its performance but you must be sure of what is controlling the abilities that you are rating. Otherwise you could very well collect a very misleading set of data.

I think that Cliff's tests are extremely useful and I wish that more people would do those kinds of scientific tests. Sometimes though, two knives are so different from each other that performing the exact same test on each knife is meaningless.

For instance: the first post in this thread proposed a standardized test for tip strength. Of course, knives with a thick tip will do good on this test, while knives with a thin tip will do bad. If you're trying to test the strength of the steel, each knife must have the same tip geometry for the test to have any meaning.

There are some standardized tests for corrosion resistance though, like the Q-fog test. It would be nice to have a standard test that all independent testers perform.


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Cerulean

"Just because some folks think you make great kydex sheaths doesn't make you into some sort of mind reading psychologist." -Paracelsus

[This message has been edited by cerulean (edited 03-31-2000).]

 

[Cliff Stamp]

Will :

do you think it's possible to set up a protocol that would fairly test performance of any blade in a way that would make it fairly measurable against any other?

Yes. The main problem I have now is to make the work broad enough to cover all the relevant issues. For example, referencing your blades, since the Deerhunter and Boye Cobalt hunter fractured at the edge during the cardboard cutting it would be possible to get a distorted view of their performance relative to the dendritic steel hunter.

To be specific, you start off and get a slicing index. You then do about 4000 cm of 1/8" cardboard cutting and repeat the slicing index and find that the Deerhunter (DH), Dendritic Cobalt (DC), and Dendritic Steel blade (DS) are all slicing well. You then conclude that the edge holding is similar. You have now "scientifically proven" a lie.

The problem is that the DH and DC blade fracture so while their slicing performance is decreased by the edge distortion, it is raised by the edge chipping (microsaw). The DS blade on the other hand, gets distorted and wear less, but since it does't fracture as readily it doesn't gain the same slicing advantage as the DH and DC.

To illustrate the difference you have to record the slicing performance between the 0 and 4000 cm of cardboard cut which will show the DH and DC blade worn but not fractured. And at a long term point say 8000 or 12000 at which point the DH and DC blade have long stopped cutting because the edge is too fractured and the DC blade will have gotton its "second wind" as its edge will start to fracture. (I am just estimating the latter issue, it seems reasonable but I have not actually done it).

You can also show the difference between a fractured edge and a well formed one by doing a push cut (the string measurements). However the string must be much larger than the size of the fractures or else you can get distorted point effects.

cerulean :

Sometimes though, two knives are so different from each other that performing the exact same test on each knife is meaningless.

It is just harder to get the information you are looking for as you must be able to account for the variation. With knife geometries this is not trivial, it is possible though. Of course it can be examined the same way the different steels can be examined.

-Cliff

 

[SDouglas]

I believe that it is important to factor the Knife's design function into the development of a suite of standard test. For instance you will probably not get much useful information by performing a Chopping test with a Filet Knife.

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AKTI Member No. A000370

 

IMHO a knife is quite often use to cut, so why not talk about a cutting test first?

Then, a knife that is REALLY used, will have to be (re)sharpened many times, so the cutting behavior "out of the box" is not too important.
This lends to a cutting test with a standardized honed edge on standardized material, with standardized pressure, using the whole length of the blade.
Just as you do mostly when cutting.

The longitudinal force required to move the blade through the substrate can be measured and is an indication for the "cutting ability". (The less, the better)
Furthermore when this force has, let's say, doubled or tripled, you have reached the end of "usefull life" of this edge. Just count the number of cuts performed and you have a nice "cutting life" index number.
Resharpen and do it again. If the figures coincide, you have a valid test.

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D.T. UTZINGER

[This message has been edited by ZUT&ZUT (edited 04-04-2000).]

 

[Ksetayesh]

Hello.....
I am doing some study on how to measure sharpness on blades. Any information would be appreciated.

Originally posted by MickMan:
I think scientific tests can provide valuable info that makes all hype less effective, and hidden (conveniently ommited) facts exposed. Also, people would be less interested where the knives were made, and by whom. Knife experts could perform these tests in a lab setting, under identical conditions for different knives. The things that would need testing could easily be quantified and presented in a nice table. No hype, favoritism or bias. Some of the things I would like to see tested:

- how much force is needed to crack the lock (on a folder) in different directions (up, down, sideways) and at various points on the length of the blade.
- tip strength (use a machine to make sure equal force is applied every time)
- slashing/thrusting in a medium
-corrosion resistance (like saltwater immersion for example)..

These were just off the top of my head and I am sure there could be more. The reason I thought about this is because too many times knife reviews (especially on the forums) are written from a biased (although well-meaning) viewpoint and cover info that may have little meaning for others.

[This message has been edited by MickMan (edited 03-30-2000).]

 

[Cougar Allen]

There's a team of researchers developing and improving knife testing methods, but you have to pass an intelligence test before you can join it. You have to be smart enough to find the Knife Reviews and Testing Forum....

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-Cougar Allen :{)
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This post is not merely the author's opinions; it is the trrrrrruth. This post is intended to cause dissension and unrest and upset people, and ultimately drive them mad. Please do not misinterpret my intentions in posting this.

 

Please reread all those tests and then think heavily.
Maybe you will then find out why this post was posted. Just keep trying.

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D.T. UTZINGER

[This message has been edited by ZUT&ZUT (edited 04-05-2000).]

 

[Will York]

MickMan--
Some of the structural integrity questions in your post, such as lock strength, would seem to involve a lot of variables. Maybe if we could get a good handle on edge testing, then move on to durability in all its forms?


[This message has been edited by WILL YORK (edited 04-05-2000).]

 

Will York:
GREAT! You got the idea => why not start with a cutting test. IMHO a knife is (mostly) made for cutting and not as a prybar.
Happy cutting to all.

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D.T. UTZINGER

 

[not2sharp]

Maybe what we need is standardize labling system. Something where the manufacturer warrants the knife as suitable for a specific purpose.

 

[Cliff Stamp]

Sdouglas :

I believe that it is important to factor the Knife's design function into the development of a suite of standard test.

That would be relevant to discussing the results in terms of the makers skill, but you should not be so limited in the scope of work.

Zut, by longitudinal do you mean in the direction of the cut? For slicing work there are two forces required, you must push hard enough perpendicular to the cut for the microteeth to penetrate the material and then push hard enough in the direciton of the cut for the teeth to tear through the material. The perpendicular force is much more than the parallel one. For a push cut only the perpendicular force is required.

IMHO a knife is (mostly) made for cutting and not as a prybar.

Strength / durability are of critical importance in cutting ability and edge retention. If you doubled the strength/durability of a steel you would be able to make a far better knife. The primary reason they are downplayed by many is that they are very easy for someone to determine and thus cannot be easily hyped.

-Cliff

 

[MickMan]

Basically what I want from a test is information that I cannot get for myself for various reasons. I can handle a knife and determine how it "feels", how comfortable it is to wear, and how smooth the action is, but I cannot do destructive tests. That should be handled by an independent entity, as they do for example, with cars.
How sharp a knife is, I suppose that could be measured optically. Blow up the edge (with a microscope) and (before and after machine-cutting tests) measure the edge across (on multiple locations, then get an average) the same way microorganisms are measured. But also, generally, one can pretty much get an idea how sharp a knife can be potentially, by looking at the hardness (RC measure). And yes, one can test brittleness too.

[This message has been edited by MickMan (edited 04-07-2000).]