Super Steels: What's the point?

hardheart said:
I believe him, it is a single account dealing with one person and two specific knives. Anything can happen, at least once. And anything can be the cause. There's no reason to call him a liar, since there's no reason to think he is lying.
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Like I said I believe it happened. However, S30V dulling in 2 cuts on the rope, unless the rope was 3ft in diameter sounds like a problem knife(HT, sharpening, user error, whatever), not a problem steel.

As he said:
Pete1977 said:
I have dulled S30V in 2 cuts on rope.
...
I haven't used anything more "super" than S30V because that Military was enough to teach me that the steel doesn't make the knife. Shortly thereafter I used a Schrade trapper in 1095 that outcut pretty much anything I had in a more "super" steel.
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I disagree with the conclusion he makes that the steel doesn't make the knife. Of course it does. Top notch HT, optimized for specific tasks can only bring out what's in the steel based on its composition and manufacturing process. There is no voodoo involved, or at least I hope it isn't ;)
 
It is still important to get real world results and to understand the limits of testing. I have test results where 420HC outperforms BG-42. I have results where 154CM outperforms S125V. That's why I can believe damn near any results now, because the variable are entirely too overwhelming in their effects. That's why I posted earlier that two or three times the performance of one alloy over another seemed high. I haven't seen a difference between alloys greater than the difference between changing edge angle on identical blades. It's why people can say such and such company's AUS8, 420, 8Cr, etc are good - the geometry is good.

The results of tests don't equate to results in use. Not unless you control for the same variables and have a full description of the conditions.
 
hardheart said:
The results of tests don't equate to results in use. Not unless you control for the same variables and have a full description of the conditions.
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That's the difference between a good test and a bad one ;)

I will agree that edge geometry is extremely important. The fact is, a knife in S30V with a very thin edge should hold that edge about as well as, if not better than, a knife in inferior steel with a thicker edge; but with vastly increased slicing performance. That is the point of super-steels, in my opinion.
 
Anything with a thin edge will hold an edge longer with better performance, you never want a thick edge for cutting. The point for any knife steel is to take it as thin as it will go with as low an edge angle as you can work with. The point of super steels is increased wear resistance, and they aren't cutlery steels. They have been adopted to our use by same makers/customers.

I have nearly 60 pages of CATRA test results and 16 test blades waiting metallurgical analysis, so don't back-talk me :D
 
hardheart said:
Anything with a thin edge with hold an edge longer with better performance
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I suspect you worded this wrong. 420HC with a 20 degree inclusive edge will not hold it as long as S30V with the same edge angle. It will perform better than S30V with a 40 degree angle, but it won't hold the edge longer.

Also, I don't think you understand the definition of "back-talk". ;)
 
hardheart said:
It is still important to get real world results and to understand the limits of testing. I have test results where 420HC outperforms BG-42. I have results where 154CM outperforms S125V. That's why I can believe damn near any results now, because the variable are entirely too overwhelming in their effects. That's why I posted earlier that two or three times the performance of one alloy over another seemed high. I haven't seen a difference between alloys greater than the difference between changing edge angle on identical blades. It's why people can say such and such company's AUS8, 420, 8Cr, etc are good - the geometry is good.
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I understand that, and I have nothing against real world results. However, geometry and other variables can not be used to determine steel A vs. B. In other words, all variables should be equal or very close to make the statement that steel A outperformed steel B, unless the steel can't support particular geometry. Otherwise, it's just a knife A doing better than knife B, in that particular test... I don't argue with that, there are tons of reasons why that could happen.
I argue that it is incorrect to make assumption about the steel using two vastly different knives used in one test, and I can argue that properly HTed and sharpened S30V will not dull in 2 cuts of the average rope either.



hardheart said:
The point of super steels is increased wear resistance, and they aren't cutlery steels. They have been adopted to our use by same makers/customers.
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They are also newer, made with better technologies and have higher working hardness and toughness (not uniformly but still). All that helps with what you said, attaining thin edges without excessive chipping.
 
Give me a knife made out of the liquid metal that the T-1000 was made of in Terminator 2.

I only care about super-steels for the sake of conversation and curiosity.
When it comes to actual use, I will use any good stainless steel.

Knife Club homework assignment:
You're gonna start an argument with a total stranger.
You're gonna start an argument, and you're gonna lose.
Now this is not as easy as it sounds.
Most people, normal people, do just about anything to avoid an argument.
(Fight Club reference. :tongue:)
 
Pseudonym said:
I suspect you worded this wrong. 420HC with a 20 degree inclusive edge will not hold it as long as S30V with the same edge angle. It will perform better than S30V with a 40 degree angle, but it won't hold the edge longer.

Also, I don't think you understand the definition of "back-talk". ;)
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I didn't word it wrong, but I don't know what you are trying to say. Reduce the edge angle, you increase initial sharpness and length of edge holding. Again, I have my own and other test results to corroborate this. 420HC at a lower angle held an edge longer than ATS-34 and BG-42 at more obtuse angles. This is how Buck developed Edge2K. When I say lower angles last longer, I mean 5, 6, 10 times longer for the same steel. And again, I don't see that level of difference between steels when the edge geometry is the same. Twice over is possible, but then all you have to do is lower the edge angle on the poorer performer and it takes the lead. Of course a more wear resistant steel is going to display that extra resistance, I am saying that for any steel you reduce the edge angle if you want the edge to last longer.

No matter what steel is in your knife, nearly every single factory edge is leaving tons of performance on the table.
 
hardheart said:
I didn't word it wrong, but I don't know what you are trying to say. Reduce the edge angle, you increase initial sharpness and length of edge holding. Again, I have my own and other test results to corroborate this. 420HC at a lower angle held an edge longer than ATS-34 and BG-42 at more obtuse angles. This is how Buck developed Edge2K. When I say lower angles last longer, I mean 5, 6, 10 times longer for the same steel. And again, I don't see that level of difference between steels when the edge geometry is the same. Twice over is possible, but then all you have to do is lower the edge angle on the poorer performer and it takes the lead. Of course a more wear resistant steel is going to display that extra resistance, I am saying that for any steel you reduce the edge angle if you want the edge to last longer.

No matter what steel is in your knife, nearly every single factory edge is leaving tons of performance on the table.
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Guess there's no point in using microbevels, then.

Anyway this is why your post makes no sense to me:

Joe Talmadge said:
The advantage of the better steel is that it is strong and tough enough to hold up with a small edge angle
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Only if there is an issue with edge durability at your relief angle. The least resistance to cutting forces would be with a blade less than a micron thick, like if you could get blade stock at 0.22 micron thick to match the edge radius of a stropped blade like in those of Verhoeven's Knife Sharpening Experiments.

But of course we cannot make a knife out of steels that thick, because there is no way they would hold up to any use. So we thicken the blade as it moves away from the cutting edge to add strength and rigidity. Every bit we add strengthens the blade overall and also makes it a less efficient cutter. The key is not to make the blade too thick for what we want to do. The thinnest stock, the lowest primary grind, and the lowest edge angle that the steel can handle for the given task will give the best performance in pure cutting tasks. If you want to chop or baton, different story. But blades with higher hardness have a greater resistance to plastic deformation, so can be taken to lower angles.
 
I understand what you're saying about performance, but the idea that it will increase edge holding/stability by making it thinner makes no sense to me. I was under the impression that the point of using a microbevel (besides sharpening convenience) was that the thicker angle increased edge stability while maintaining most of the performance benefits of the thinner main bevel.

Bah! Challenge my preconceived notions, will you?

I'm certainly no expert, but that's what I've been led to believe and everyday use seems to have confirmed it (or at least not disproved it). If you're interested, my everyday use has ranged from cutting tape to cutting boxes, plastic straps, and blister packs.
 
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You have to think at those small scales. A knife goes dull in the first few microns of edge. Again, any steel past that is getting in the way. For any given force applied by you in cutting, any that is used in wedging the bevel sides against the media is not used at the cutting edge to cut. By reducing the angles, we reduce the wedging forces and concentrate more on cutting forces. In that, for the same amount of effort we put into a thicker knife, a thinner knife does more cutting.

You can only get the final edge apex so small in radius, we can't sharpen to atomic levels. It is like airplanes, you get an engine with only so much thrust, just as you get an edge of only so small a radius. The plane that flies farther, faster, for given amount of stored energy in the fuel burned by that same engine is going to be the one that is more aerodynamic and encounters less resistance to cutting through the air.

The edge itself is going to wear, so every knife of every profile will dull. What happens while the edge is dulling is that it is taking more force to cut, while it is also taking those same wedging forces to move everything past the edge apex through the material. Reduce the overall forces and you cut longer.
 
Well the way you're describing it makes it sound like steel doesn't matter at all. Can someone else weigh in here and tell me if I'm being completely thick-skulled?

The only thing I can take from it is that a thin edge with a roll will still slice better than a thick edge with no roll. Does that sound right? Even if it is, that thin edge is still the one with the roll in it...
 
Steel matters in terms of properties like working hardness, wear resistance, toughness, corrosion resistance, etc. The higher the hardness and wear resistance, along with a fine carbide structure, will let you take the knife edge down to very thin levels and cut for a long time.

Steel doesn't matter in a certain envelope of performance. Like I said, there is a lot of overlap between alloys and edge profiles up to a certain amount of cutting. You need a level of abrasive wear and matrix strength to get beyond that, but a lot of knives can do the same amount of work depending on how they are sharpened.
 
So you're saying that better steel just increases the range of angles it can support? Cuz I'm pretty sure that's what I was saying, though maybe I oversimplified it a bit.
 
Sort of. It depends on what we want to call better. You can use 1095 at 64 Rc at low angles, now is that better than 440C at 58. Steel is going to be about the whole mix of properties, not just which has the best abrasive wear resistance, or highest attainable hardness, or highest impact toughness.
 
hardheart, I recognize you as a knowledgeable person; I think you know you stuff more than most here. Would you agree that there are simply too many variables in how a knife can be made to give broad generalizations as to which is the best?
 
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