Is everyone buying their knifes wrongly or i am getting something wrong?

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PlumasDePan

Joined
Jul 21, 2020
Messages
47
All over the internet, i see people buying knives in S30V, M390, M4...Etc
They buy them because I guess they expect better edge retention. But from what I have seen, without the propper abrasives and sharpening tools. You will get carbide tearout. Which I am starting to think that it affect the performance a lot more than what people give credit to.

Here is a video of this guy sharpening s30v in a edge pro and comparing the result to 8cr13mov
I understand that there are probably other factors going on on this result. Like for example that he is just seeing how long it cuts hair instead of how long it takes to dull.
But I think that it still shows a disappointing result under s30v which doesn't match with what other people have tested. However, all these other people like knifesteelnerds or cedric and ada have shown to use proper abrasives.

Where I am going on with all of this? I think that people should choose their knives in pair of what abrasives are you going to use to sharpen it. If you are going for something like a good ceramic stone you shouldn't go higher than cruwear(And i am not even sure of this). And if you don't want to spend in sharpening equipment maybe something that has less hard carbides would be more beneficial?

What do yu guys think?
 
Edge retention testing is all over the place. So you know what? I don't worry about it, and neither should you. Use whatever abrasives you want because carbide tear out is a myth, although some abrasives are more efficient than others (diamonds).

Why even worry? Buy a knife you like, sharpen it how you like, and use it. If it performs admirably then great! If not, sell it and try something else. The world of edge retention testing is interesting, but there are way too many variables and people are getting results that are all over the place. Two knives of the same steel are probably not going to have the same exact hrc numbers, and what about geometry?

Things like this can keep you up at night for no good reason. Or you can be up because your toddler decided not to sleep...
 
I think a lot of the issue has to do with trying to quantify something that is a personal qualification.

Some wont be happy unless they can polish an edge to a mirror that will slice free hanging tissue paper. Some simply require an edge just north of "butterknife" that can be pushed into service for years without touching it up.

My personal preference: I dont let my edges go dull...period. its just like I dont drive my car until the check engine light comes on. I can maintain any steel I purchase with ceramic rods and a loaded strop. If I happen to damage the edge beyond that, I have a couple of inexpensive diamond hones that will get it in good enough shape for me to finish up with rods and strops.

One of the traits I value on an outdoor/camping knife is that it be made from a traditional carbon steel over a super steel. In the event of an emergency, i want to be able to get a workable edge with an Arkansas stone.
 
In terms of 'rope cutting edge retention' test, I think the outdoors55(the youtuber) did a pretty good job explaining what he think could be the variables, and did try to control those variables as much as he could in his tests. And I tend to agree with his findings--that within those two samples, Spyderco did a fantastic job with that particular Tenacious, and his S30V was not bad either, since he did mention it was on par with other knives of his.
 
A good Ceramic / SiC / Aluminum Oxide stone can be harder than you think.
 
I think testing like this is inherently unscientific as there are massive uncontrolled variables at work. One of the very first issues is that his end point 'it won't cut paper' itself relies on a significant number of variables. To be perfectly frank, I think an unexpected result like poor performance of S30V vs 8cr13mov in testing like this calls into question the validity of the testing much more than the edge retention properties of the steel or what media should be used to sharpen.

For an example of a much, much better (though exponentially more expensive) edge retention test, you can refer to the CATRA testing done by our own @Larrin here. https://www.bladeforums.com/threads/i-tested-the-edge-retention-of-48-steels.1726279/
 
Insipid Moniker said:
'it won't cut paper' itself relies on a significant number of variables
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Not to mention bias, intentional or not. I didn't watch the video, but if he set out with the hypothesis that 8Cr13MoV is "just as good" as S30V, He's more likely to look for results that confirm that. Paper cutting is subjective enough that I'm sure I could push "dull" 8Cr through paper, and have issues cutting with "sharp" S30V.
 
Silent H said:
Not to mention bias, intentional or not. I didn't watch the video, but if he set out with the hypothesis that 8Cr13MoV is "just as good" as S30V, He's more likely to look for results that confirm that. Paper cutting is subjective enough that I'm sure I could push "dull" 8Cr through paper, and have issues cutting with "sharp" S30V.
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I watched his tests, and there is no bias. He tries to control all the variables he can. Watch the videos, see what his methods were, see how the knives perform. Personally, I thought he did an excellent job with the tests, explaining his methods, controlling variables. Any of these youtube tests should be taken with a grain of salt, but his results do call into question if we can trust any of the tests at all, including his own.
 
soc_monki said:
I watched his tests, and there is no bias. He tries to control all the variables he can. Watch the videos, see what his methods were, see how the knives perform. Personally, I thought he did an excellent job with the tests, explaining his methods, controlling variables. Any of these youtube tests should be taken with a grain of salt, but his results do call into question if we can trust any of the tests at all, including his own.
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I watched it and strongly disagree with literally everything you've said. His end point (cutting paper) is poorly defined and not a good or accurate measure of edge deterioration. Cutting by hand is a massive variable as the angle of cut and force behind the cut can vary significantly, as can the portion of the blade being used in cutting. Saying, "there's no bias," is both unhelpful and untrue. Bias is unavoidable, good testing protocols aren't about limiting the bias of the testers, they're about eliminating ways in which bias could affect the results of the test. The idea that this would call into question something like the CATRA testing I linked to just doesn't seem sound in the least, given that testing has removed many, many more variables and is much more tightly controlled.
 
Insipid Moniker said:
I watched it and strongly disagree with literally everything you've said. His end point (cutting paper) is poorly defined and not a good or accurate measure of edge deterioration. Cutting by hand is a massive variable as the angle of cut and force behind the cut can vary significantly, as can the portion of the blade being used in cutting. Saying, "there's no bias," is both unhelpful and untrue. Bias is unavoidable, good testing protocols aren't about limiting the bias of the testers, they're about eliminating ways in which bias could affect the results of the test. The idea that this would call into question something like the CATRA testing I linked to just doesn't seem sound in the least, given that testing has removed many, many more variables and is much more tightly controlled.
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Which is why I said I take all tests on YouTube with a grain of salt. And he was even surprised at the results. 8cr13mov is crap steel, supposedly, yet it seemed to keep up with S30v cut for cut. He eliminated as many variables as possible, but even said he couldn't control them all. He tried to be as fair as possible. How is that being biased? He gains nothing from doing these tests.

It's kind of like the supersteel Steve tests where he debunked the carbide tear out myth. It was laid out for all to see yet people still don't believe it. Yes, there are still uncontrolled variables, and again take it with a grain of salt, but it still gives some data that says something a lot of people swear is true when it probably is not.

CATRA is honestly the only test that gives actual admissible results because of the controls in place. But not everyone has a CATRA machine either. I will take CATRA results over all others though.
 
soc_monki said:
Which is why I said I take all tests on YouTube with a grain of salt. And he was even surprised at the results. 8cr13mov is crap steel, supposedly, yet it seemed to keep up with S30v cut for cut. He eliminated as many variables as possible, but even said he couldn't control them all. He tried to be as fair as possible. How is that being biased? He gains nothing from doing these tests.

It's kind of like the supersteel Steve tests where he debunked the carbide tear out myth. It was laid out for all to see yet people still don't believe it. Yes, there are still uncontrolled variables, and again take it with a grain of salt, but it still gives some data that says something a lot of people swear is true when it probably is not.

CATRA is honestly the only test that gives actual admissible results because of the controls in place. But not everyone has a CATRA machine either. I will take CATRA results over all others though.
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Trying to be as fair as possible has little to do with bias, as it's often subconscious. Even your expectations of which steel will perform better can subtly influence how you perform the tests you're performing. Unless he was performing a blind test in which he didn't know which steel was which and was doing so with identical blades then we can't eliminate personal bias as a possible factor when someone is cutting by hand, especially when there were literally no parameters defined for the paper cut tests.

You stated that testing like his calls all other tests into question, and it very much does not. As per the article and thread I linked to, we have access to testing with vastly superior methodology. If those two tests seem to contradict each other the logical thing to do is to question the findings of the test with worse methodology, which is unquestionably the test presented in the video, rather than questioning the other testing data we have access to.
 
The problem with a lot of these tests is that they only test 1 blade (or very few) and then try to have them represent all knives in that steel. I've always been told that N=1 means N=None. The S30V knife he had could have been a lemon, could it not?

To be fair, this is just hobby work, and just a bit of fun (at least I hope so, it costs a lot of time!). And I do appreciate it as a data point. But thorough testing on multiple blades is probably too expensive and time consuming for most people. It does make you think, though. How do manufacturers test this? What is the basis of the claims for the newest 'super steel'?

In the end, a skilled maker will get you more use out of a lesser steel than an unskilled maker would get out of a 'super steel'. Be a discriminating customer and be critical in sourcing your knives first, then look at steel second.
 
Carbide tear out is not a myth. I will concede it is rare and not nearly the problem that people make it out to be, but SEM imaging has proven it does happen. Super Steel Steve has been wrong or over zealous on more than one thing.

The general rule of thumb is switch to diamond/CBN at 4%+ vanadium. Especially as the grit progresses. SiC and AlO are softer than the vanadium carbides. They will primarily sharpen the steel matrix around the carbides. At lower grits, it's not that big of a deal because the carbides are small enough that it doesn't have much affect. But, if you start moving up in grit, you start getting a very sharp steel matrix with burnished carbides protruding. The steel matrix, now not being well supported will roll (dull) faster.

You also put more wear and tear on your ceramic stones with higher vanadium carbide steels.

That said, the steel composition itself is only one line of the triangle. You need heat treat and geometry factored in as well.

If you're Michael Christy or Big Brown Bear (@DeadboxHero ) you can sharpen high vanadium carbide steels and then proceed to whittle 2x4's and split nails and still split hair. Those steels can hold exceptional edges if you have the proper triangle, tools, and skill.

But most people will notice that the fine edge on most of their knives disappears rather quickly, especially depending on the medium being cut. Sisal rope and cardboard are horrid on edges. But I can absolutely tell the difference in my Manix 2LW in S90V and BD1. The S90V will keep a cleaner edge longer. May not shave hair or make curly-q's in receipt paper but it will still be cleanly cutting cardboard longer than the BD1.

Which is all well and fine, but me, being like most general EDC folks, it will take a looooong time to notice this. The average EDC carrier can get by just fine on fairly basic steels. Especially considering how soft a lot of the high carbide steels are ran. People get googly eyed over the nomenclature and they shouldn't.

I cut down some very stout cardboard recently. I once again used my M2LW's as a side-by-side. The BD1 became more of a chore much faster than the S90V. I've seen this before. But, my hand hurt way before either one started giving up and both needed sharpening after.

Buy knives you like. Matching steels and HT to specific tasks is great. But beyond that, steel's performance should be down the list of cares.
 
But, but, it's The Final Word!




Even though at around 3:30 he states that it's ruled inconclusive:rolleyes:
 
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