Is this a joke? No one other than Spyderco and Buck and a random maker here and there test for edge retention? Get real. Just because someone doesn't want or feels like giving some smart Ass on a forum every detail that they demand doesn't mean they haven't done it.
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bending tests
- Thread starter Toni Oostendorp
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I think you give manufacterers too much credit. Take S30V for instance. Chris Reeves and Paul Bos decided to go with 58-59 hrc and everyone else follows their heat treat, even though independant testing shows 60-61 rc to be more optimal. Nothing against Paul Bos, he did a fantastic job on my S30V @ 60-61 rc. Just saying, I see a lot of instances of copying whatever the industry leaders do rather than manufacterers doing their own testing. Spyderco does their own testing, which is why you see them hardening their steels 1-2 rc points harder than the rest of the industry.
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Unfortunately, edge retention is sometimes not of paramount importance to manufacturers. I've heard Mike Stewart say that he could push his A2 up to 60 HRC, which might even increase its toughness a bit, but doesn't because it is harder to sharpen 
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You know Vassili, it is how you ask it......
I do a lot of testing, from rockwell testing to bending knives. But the way you ask for information doesn't really inspire me to put my time and energy in it.
Greetings,
Toni
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I for one am impressed a tool steel bent like it did, I am almost interested in knowing the rockwell it came out at as tested. Even same pieces of a single sheet of steel can heat treat differently in identical knives, but you seem to have it down.
As for Vassilli, he's on thin ice, it's only thing to question a few things about a knife after being tested, but the down right trashing and demanding tone from him are outright wrong.
As for Vassilli, he's on thin ice, it's only thing to question a few things about a knife after being tested, but the down right trashing and demanding tone from him are outright wrong.
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these cutting competitions cuts are a WAY better test of edge sharpness & strength than whittling a hair (or many of the tests you see for that matter).
I can't see how they do a better job on sharpness. These competitions test a system, knife + user. Doesn't matter how sharp your knife is if you miss the rolling ball. I don't see much point in testing 'sharpness' anyway, doesn't seem there's any cutlery grade steels that won't hit the same level, at least for one cut. Really, I don't know if it's too valuable on strength either. We'd need to know all the parameters of the edge & bevel, not just the steel used, to get anything useful from that. I enjoy the novelty of tests and comparisons, but am losing any feeling of advancement from them because of the unaccounted for variables and lack of validation through repeated testing.
I just think they're cool events, but they're about as useful in determining best steel as NASCAR is for saying if Ford or Chevy is better. Still have drivers, crews, weather & track conditions, etc. to look at. Better to just watch and enjoy. Well, if you can enjoy watching a bunch of guys turn left for hours on end
I'm not trying to poke you with a stick, but want to reply to this.
The strength of an edge is very important - if the edge is not strong enough to make the cut, bad things happen to it. Of course edge strength is a combination of various factors, and they are all tested during a cutting competition. If any factor falls short, the result is edge damage, and the knife is DQ'd. You absolutely will know that the knife in question has an edge that stayed sharp while making those cuts, & not get damaged in the process. And even if you did quantify every factor that contributes to it, you still will only know THAT ONE combination of those factors did it (highlighting the lack of any useful hypothetical relationships or models for cutting, or any large scale empirical test data).Whereas a hair whittlin' knife could lose that edge after one cut through rope, due to bad sharpening or geometry. A really sharp knife doesn't do one much good if the edge folds over like an accordian after one cut.
Thus imo it is obviously a better test than whittlin' hairs - I have a friend that has hair that any knife I carry can whittle, yet very few can whittle my daughter's hair. So when see a picture of a whittled hair, it tells me that the knife is at least pretty sharp, but maybe/probably not tree topping blonde arm hair or slicing a tube of phone book paper sharp. So I'll take an edge that can succesfully go through a cutting competition over one that can whittle a hair every time.
Sharpness needs to be tested if you are going to do scientific testing, and want to start with equal sharpness. These competitions are not scientific tests, but they contribute more to the knowledge base than some of the tests that do claim to be scientific (ahem).
What good would it do if someone did quantify every aspect of all the factors that contribute to the knife successfully making these cuts without damage? You'd still just know that that one knife, with those attributes, made the cuts without edge damage or blade failure. And we still could not scientifically state with any assurance if a knife otherwise identical, but with only one characteristic changed, could successfully make those cuts without edge damage. So while I agree that it would be interesting to know all the geometry and properties of the knife, knowing them would not take us further towards an understanding of why they all worked.
This highlights what scientific testing can do - practically for our purposes, it can make comparisons of one cutting variable. Because there is very little theoretical understanding, even years of empirical scientific testing might only get us a couple baby steps closer to a true theoretical understanding (just like years of testing has with toughness, hardness, liquid flow, gas flow, heat transfer, and on and on) Every practical (ie. used for design purposes) equation in a heat transfer textbook or propeller design textbook was empirically obtained with little or no theoretical basis.
For example, if you had otherwise identical knives, and varied edge angle from 30 to 40 degrees, and tested for force to cut manilla rope, you would be guessing to use those results to figure out how much force a 20 degree or a 45 degree edge would require to make the same cut. And you would not know if the 20 degree angle would be strong enough to make the cut without damage. You could use numerical methods to draw a best fit line, but that would be extrapolating test data when you have no clue of the real relationship that controls the behavior.
Thus my belief that an emprical understanding is the best we are going to do on the theory of cutting. We can use known geometry & physical properties to conjecture using our metallurgical understanding, empirical knowledge base, & intuitition, but that is as far as we'll go, and there will always be room to disagree from a theoretical perspective.
nozh2002
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I agree, just saying that this testing should take place, and can't until we define the aspects of the competition edge. We know something works, now let's see why it works and if we can make it work better, or adapt it for other profiles.
Now come on you know that isn't true. Everyone didn't do the same as CR and PB heck you even pulled up a thread a few weeks ago "S30v empressions " from 02 that showed S30V hardened to 61 RC. I have the Carson knife that is one of the first 2 he made back before S30V was widely available. This knife was tested by me and I know that Kit and other users tested the steel as well. As Thomas and Kershaw have also been brought up I do know that they have done the same thing with some of the steels they use. I even know there are a few BFC members that were lucky enough to be one of Kershaws "testers", not sure I should call them testers. I also think that you could say that Spyderco is one of the leaders in the knife world and most everyone would agree to that. So why doesn't everyone blindly follow them and harden steel to the same as Spyderco?
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nozh2002
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Sure you found some exceptions, but the majority of the industry still heat treats S30V to 58-59 rc. They've done so in the past and do so today. I can understand that it makes the blade easier to sharpen, at least the argument. However, with better edge retention, the less often you need to sharpen.
Companies don't follow Spyderco because the hardness numbers are not published. I know that their steels are hardened a couple points harder than most of the industry, but few else do, as it is not advertised.
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I agree that the ABS has it all wrong. Bent blades are impressive, but I think this is the wrong direction for the knife industry to go. If you're in a situation where your leg gets stuck under a car, and you use your knife as a lever for prying, I'd rather it snap than become permanently bent. At least I would be able to cut with what remains of the knife (to cut clothing and tend to my wound). Whereas the bent knife is completely useless, and it couldn't even go back into its sheath. Broken knives are preferred over bent knives in real-world situations.
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The ABS tests demonstrate a smith's ability to manipulate the properties of a blade through selection of steel, heat treatment and geometry. They do not demonstrate the quality of a knife.
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Give me a break. It is not an insult to anyone to affirm every member's right not to answer every idiotic question from every smart a$$ on the forum. db did not call anyone in particular a name, he just stated the obvious without naming any member. You had to assume which one ding-dong in particular he was making that statement about.
That's fine, but any designer worth his salt knows that really bad things happen when steel fails catastrophically in use. Your Mom or wife will sue the knife mfg after you are unwise enough to put all your weight into trying to pry (a car off someones leg!
) with your 60HRc S30V knife, it snaps (and it will probably take all your weight and an unwise prying location to snap it), and then you fall backwards into the lane of traffic and get run over by a bus (or beat on it with a hammer and get a piece of shrapnel in your eye). I don't disagree with your logic that a snapped knife can still be used, but the knife that bends is less likely to injure, and that is obviously a MUCH bigger concern for a knife mfg or maker.- Joined
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