Cardboard cutting; Steel vs. Geometry

dkb45 said:
I think I should make it clear that I think Gaston and his points are not only unfounded, but also laughably incorrect. I've seen first hand how blood great super steels are. My Cru-wear Manix and K390 Urban have shown alone that there are steels that just make normal steels like even D2 look like garbage, which in their own right are not bad steels at all. I did some very unscientific testing with some cardboard cutting, and despite cutting around 50% more than S35VN, my Cru-wear Manix was just had the slightest diminish to edge sharpness.
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Oh really? You've seen it right...



gadgetgeek said:
I'll agree to that, what I'm disputing is this notion that seems to have flared up that there is no benefit at all to a higher end steel.
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There is a benefit to higher end steels: Well treated 440B/C, Japanese treated Aus-6/8, and to lesser extent, D-2, are high end steels. S30V, CPM 154 and CPM 3V are low end steels.

I don't know about the others, but call me skeptical. Healthily so.

gadgetgeek said:
I think its clear enough that a higher end steel can be pushed farther as far as geometry goes. .
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If "farther" means thinner, that is emphatically true. The problem is the "higher end steels" are not the ones you think they are... Also, thinner geometry can boost edge holding performance, so if you assume the wrong steel is "better", based on novelty, and give it a thinner edge geometry on that basis, then you are boosting the inferior steel at the expense of the better steel.

What is great about checking for micro-folding, after some light chopping, is that it is an entirely objective binary result: Either the apex grabs the nail material on one side, or it doesn't. There is little in between, except for the extent and continuity of the grabbing.

"Normal" paper-cutting sharpness tests by comparison are largely meaningless: Paper tells you little about the apex condition (except immediately after sharpening, de-burring and cleaning) and neither does it tell you much about the apex stability: An edge that degrades less, but to a rougher apex, will find the apex roughness more clogged with tiny particles, and so this clogged "lesser" apex will tear paper, even though it is both sharper and not leaning to one side like the "superior" CPM cutting edge is...

This probably explains why people are convinced they see large edge retention benefits with CPM steels...

I don't even see much in the way of careful edge-cleaning/wiping between "paper tests" on most videos, nor did I hear of it in any posts...: No verification of apex clogging. Pretty much says it all...

Gaston
 
I think you are wrong about paper cutting tests. If a knife will still cleanly cut paper, then it will cut just about anything else. Also, while on this topic, i did over 100 cuts through cardboard with m390 and would still slice paper towel without tearing, and over 1000 cuts through rope with s30v and their was no "micro folding" or "micro edge roll" and i do check for it with my thumb and fingers. If you are having problems with your s30v "micro folding", i would suggest getting in touch with the manufacturer because it shouldn't be doing that.
 
Gaston444 said:
Oh really? You've seen it right...





There is a benefit to higher end steels: Well treated 440B/C, Japanese treated Aus-6/8, and to lesser extent, D-2, are high end steels. S30V, CPM 154 and CPM 3V are low end steels.

I don't know about the others, but call me skeptical. Healthily so.



If "farther" means thinner, that is emphatically true. The problem is the "higher end steels" are not the ones you think they are... Also, thinner geometry can boost edge holding performance, so if you assume the wrong steel is "better", based on novelty, and give it a thinner edge geometry on that basis, then you are boosting the inferior steel at the expense of the better steel.

What is great about checking for micro-folding, after some light chopping, is that it is an entirely objective binary result: Either the apex grabs the nail material on one side, or it doesn't. There is little in between, except for the extent and continuity of the grabbing.

"Normal" paper-cutting sharpness tests by comparison are largely meaningless: Paper tells you little about the apex condition (except immediately after sharpening, de-burring and cleaning) and neither does it tell you much about the apex stability: An edge that degrades less, but to a rougher apex, will find the apex roughness more clogged with tiny particles, and so this clogged "lesser" apex will tear paper, even though it is both sharper and not leaning to one side like the "superior" CPM cutting edge is...

This probably explains why people are convinced they see large edge retention benefits with CPM steels...

I don't even see much in the way of careful edge-cleaning/wiping between "paper tests" on most videos, nor did I hear of it in any posts...: No verification of apex clogging. Pretty much says it all...

Gaston
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I am not one to blindly agree or disagree with anything. I can't agree with you about CPM steels, but I also can't say CPM steels are next to the best either, because I haven't experienced them. However, you should understand that saying a steel that almost everyone regards as ultra premium is actually worse than D2 or 440 means nothing alone.

I have no conclusions of my own, but I can offer some advice: words mean jack #@$& in general. The only way you will be able to convince people of your view is to have an extremely controlled scientific test comparing the steels. Leave no other variables to chance. Record a video of you performing the test, no edits.

Unless you do this, your posts will forever be meaningless.

I can appreciate your grammar and seemingly scientific approach. If you are a person of science and reason, then hopefully my post will come off as informative.
 
Enough with the insults. I do not care how much you disagree with a poster, you must address the issues and not insult one another.

Two posts moved offline.
Next one gets a warning with points.
 
Gaston444 said:
and neither does it tell you much about the apex stability: An edge that degrades less, but to a rougher apex, will find the apex roughness more clogged with tiny particles, and so this clogged "lesser" apex will tear paper, even though it is both sharper and not leaning to one side like the "superior" CPM cutting edge is...
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I'm not understanding this. For one, none of my CPM steel knives have shown signs of micro-rolling, where as its been more common in other steels I've used. Secondly I don't understand this idea of a clogged edge. The only thing I've ever encountered which could be similar is having adhesive on the edge and blade which added friction to the cut, but did not change the sharpness. I'm just not seeing how a steel that has a higher ability to resist abrasion, higher tensile strength at a given hardness, and is capable of greater flexibility at that hardness could be seen as inferior. I just don't get it.
 
Do they in fact have higher tensile strength and greater flexibility @ the same hardness?
 
Yes, well, in the hopes that this discussion can be salvaged. I'm curious as to how these conclusions can be reached which are 180 degrees to the consensus.
 
I'm not disagreeing with you at all on that point. But to that end if someone is coming to the conclusion due to faulty data, resulting from faulty observation, I'd like to know how its possible so as to avoid it myself. Regardless of the externally available information, one would expect that this is the case.

me2 said:
Do they in fact have higher tensile strength and greater flexibility @ the same hardness?
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Not as a universal in every category, but if you are just going off the charts, typically I've found that the newer steels will at the very least be much better in at least one category, and if you look at what some of the custom knife-makers here are able to do, it would certainly seem to be the case. I can't find the chart I was thinking of, so I'll keep looking, but it had comparisons of exactly that.
 
Are these the same charts that list differences in wear resistance, but don't say if it's adhesive or abrasive? Let's just say I'm as skeptical of some charts as many are of the reported micro folding of edges.

Sometimes you have to dig deep to find the answer. It's easy to dismiss observations that are uncommon and/or unpopular. It's more difficult to figure out what's really going on.
 
So far all I've found are self comparative charts, nothing will much of a control, but there you go, the internet is a big place. As far as your comment of wear resistance, I think we can discount adhesive wear in most cases, I highly doubt it makes much of a difference from the point of view of the steel used, more the material being cut and surface finish.
Also don't go looking for a false equivalence between the two ideas, no one is disputing that the charts could be better. Also I'm not dismissing the observations, just trying to figure out how they could come about. But its gone on for a long time, and there is still no evidence to back up this claim that the steels in question preform so poorly.

But the burden of proof must be shared, you don't get to be a skeptic just by saying "I don't believe it" you have to come up with some work of your own, or at the very least some anecdotal observations.
 
Clogged apex? What?

I have not experienced micro folding with CPM steels and I always check for burs by dragging on a finger nail. I can only speculate but I assume that what you are calling microfolding is the result of insufficient bur removal. Possibly the result of straightening a bur out instead of fully removing it. This is something I have experienced in the past.
 
gadgetgeek said:
So far all I've found are self comparative charts, nothing will much of a control, but there you go, the internet is a big place. As far as your comment of wear resistance, I think we can discount adhesive wear in most cases, I highly doubt it makes much of a difference from the point of view of the steel used, more the material being cut and surface finish.
Also don't go looking for a false equivalence between the two ideas, no one is disputing that the charts could be better. Also I'm not dismissing the observations, just trying to figure out how they could come about. But its gone on for a long time, and there is still no evidence to back up this claim that the steels in question preform so poorly.

But the burden of proof must be shared, you don't get to be a skeptic just by saying "I don't believe it" you have to come up with some work of your own, or at the very least some anecdotal observations.
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Absolutely. I don't think adhesive wear is at work either. What I'm referring to is the use of adhesive wear to make charts that show large differences in wear resistance, when that is largely irrelevant for hand held knives. I haven't seen that done in years, but charts get thrown around and we sometimes don't know what they're actually saying.

That's what I'm talking about. I am not one to say these things aren't happening. I do think it's possibly a sharpening issue. I don't chop with steels of that nature, but I do have some S110V that is thoroughly dull after just one Costco box. I'll examine it more closely after work.
 
This has certainly been an interesting discussion.. In doing a bit more "research" with the Spyderco Military in 204P, I find that the initial sharpness of the steel contributes first and foremost and the geometry follows (and usually supersedes) very closely behind in cardboard cutting; while edge stability (steel and heat-treat) determines how long. However, the variables in heat-treat and differences in steel characteristics play a vital role within the mix. After this bit of testing, I'm finding those variables to cloud the subject, making things much more complex. I think another big factor is in how the user appreciates the cutting capabilities and characteristics applied through the heat-treat and blade geometry, rather than the scientific composition itself. I can appreciate the objective facts, however they seemingly grossly overshadow the subjective user at times. I observe a favorable difference in 204P as compared to S30V for thick cardboard cutting, omitting edge resistance and speaking specifically on how the steel cuts. For EDC cutting, I find the two less distinguishable. I believe if the bevels were ground to allow the super steels to operate at a more maximal geometry (which is debatable in and of itself), the average user would see a true difference in all of the steels offered and potentially be a turning point in seeing the commonly dismissed (and highly underappreciated) S30V take a back-seat in base models being released. That, however, skyrockets the cost; which is why S30V is favored for most standard/first release models to begin with.


I simply chose to bring cardboard cutting into the fold as a basis because many of us choose to use a knife over a box-cutter for this task. Given their exploratory nature as a company, especially when it comes to steel offerings, I'd like to see more super steels transition to the Japanese Spyderco models, since they're adding S30V to the mix and the Police 4 being in K390. The Delica and Endura seem to be a fine platform to start. :D
 
What is ignored in this thread is the user. How does he handle the knife when cutting the testing material? Is he a slicer or pusher or some combo? Lots of variables other than steel and shape of the blade. Is the material being cut identical? Lots of variables!



 
GatorFlash1 said:
What is ignored in this thread is the user. How does he handle the knife when cutting the testing material? Is he a slicer or pusher or some combo? Lots of variables other than steel and shape of the blade. Is the material being cut identical? Lots of variables!



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Technique combined with the toothiness of the edge preparation makes for a huge amount of variability in performance.
 
Our species survived for millennia using this. Carry on.

enlishknife.jpg
 
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