Why are blades rarely slicey?

[Gaston444]

I’m most puzzled at bevel angles. Decades of super steels and I haven’t seen a folder with an aggressive bevel angle... ever. I know why a manufacturer would err on the side of thick but come on, plain edge knives with more acute angles start cuts so much better.

This is because a tradition has developed of testing steels by doing non-knife like tasks (materials harder than wood). The most prominent example of this is INFI (which is better than many CPMs at true knife-like tasks, again nothing harder than maple wood): This is what happens to INFI when it is ground to a convex 32-34 degrees inclusive final, and you lightly chop some maple (below is a comparable -slightly thinner- edge in 5160):

Like many newer steels, they do not tolerate reasonably thin angles (15 dps or less), so that is why they are ground thicker, as the tests that developed them seem to favour edge holding at blunt angles (but often non-impact tasks, though INFI did well at not rolling, even if it warped easily): So gradual abrasion tests and that kind of thing.

This below is how many CPMs typically behave under chopping impact (CPM 3V here being the best, taking 20 plus hits for the apex "lip" seen here). S30V, the worst I have seen, will do this merely slicing 1/8" cardboard (Gerber 70th Mark II), or in single chops in maple(!).

Note how the cheap low-end Chinese 420J is completely indifferent to wood impact, the one short lip area being the result of an accidental twisting motion. Angles were similarly thick: Near 20 dps.

On the other hand, using the same 420J and hitting metal will yield severe edge damage as the apex compresses, while other higher-end steels will fare better... The only problem is that this superior high end steel performance appears while doing completely knife-irrelevant tasks, like cutting into metal, or maybe high abrasion tasks...

So yes, strangely enough, something that holds up better against harder (or in knife-unrelated industrial tests) will do worse, relatively, on more realistically soft mediums, at thinner edge angles, especially if chopping (the apex "lip" appearing easily under nail rubbing). The only way to disguise this is to stay safer on the side of thicker edges: Hence the non-aggressive above 15 dps (30 inclusive) edges, usually an amazing 20-25 dps, that you observed.

Gaston

 

[CoryMc]

In all reality, knife consumers are probably mostly to blame. Knife folk tend to expect any issues to be warrantied and fixed by the maker whether or not you have thrown, battoned or chopped through your car door.

If they call you an idiot for your gross negligence, the masses run right to the forums and Facebook to proclaim what a POS knife they purchased and (insert brand here) wouldn’t back their “faulty” product.

I’d make them idiot proof too...

 

[Gaston444]

I think the term survival knives started in the 70's and 80's and were so popular that so many knives were produced using 1/4" stock. Every kid and knife aficionado had to own one or a few. I feel sure that the fighting knives such as produced by Randall always used 1/4" stock and they were never slicey knives nor intended to be so. Knives just became more diversified and many lost the thin cutting performance associated with slicing.... .

Randalls come edge-dull, but are practically the only large "tactical" fixed blades to have edges as thin as 0.020" from the box. Everything else I had to have REK re-grind thinner.

Most competitors are twice as thick: 0.040" is typical. RJ Martin, Lile... Especially things by Cold Steel like the Trailmaster, or most stuff contract-made in Seki City...

Unbelievable the stuff you have to read sometimes...

Gaston

 

[91bravo]

My blades slice quite well, thank you.

 

[Gaston444]

Jeez, what counts as an "aggressive" bevel angle to you? I've seen and sharpened plenty of Spydercos ground damn near or at 30 inclusive. Seems pretty aggressive by most people's standards. Admittedly they are better than most, ."

30 inclusive is aggressive.

 

[dkb45]

This is because a tradition has developed of testing steels by doing non-knife like tasks (materials harder than wood). The most prominent example of this is INFI (which is better than many CPMs at true knife-like tasks, again nothing harder than maple wood): This is what happens to INFI when it is ground to a convex 32-34 degrees inclusive final, and you lightly chop some maple (below is a comparable -slightly thinner- edge in 5160):

Like many newer steels, they do not tolerate reasonably thin angles (15 dps or less), so that is why they are ground thicker, as the tests that developed them seem to favour edge holding at blunt angles (but often non-impact tasks, though INFI did well at not rolling, even if it warped easily): So gradual abrasion tests and that kind of thing.

This below is how many CPMs typically behave under chopping impact (CPM 3V here being the best, taking 20 plus hits for the apex "lip" seen here). S30V, the worst I have seen, will do this merely slicing 1/8" cardboard (Gerber 70th Mark II), or in single chops in maple(!).

Note how the cheap low-end Chinese 420J is completely indifferent to wood impact, the one short lip area being the result of an accidental twisting motion. Angles were similarly thick: Near 20 dps.

On the other hand, using the same 420J and hitting metal will yield severe edge damage as the apex compresses, while other higher-end steels will fare better... The only problem is that this superior high end steel performance appears while doing completely knife-irrelevant tasks, like cutting into metal, or maybe high abrasion tasks...

So yes, strangely enough, something that holds up better against harder (or in knife-unrelated industrial tests) will do worse, relatively, on more realistically soft mediums, at thinner edge angles, especially if chopping (the apex "lip" appearing easily under nail rubbing). The only way to disguise this is to stay safer on the side of thicker edges: Hence the non-aggressive above 15 dps (30 inclusive) edges, usually an amazing 20-25 dps, that you observed.

Gaston

Why do you insist on constantly repeating the same false information? INFI is literally one of the toughest stainless steels on the market. You can look up and of the dozens of videos of people absolutely thrashing their Busse knives in INFI and it takes the thrashing as well as a simple carbon steel.

As for S30V chipping on cardboard, I've cut an absurd about of cardboard at work over the year I've been here, and not a single time have I experienced any of my steels chip from cardboard. I've ran S30V from shaving to unable to slice paper, not a single chip. Simple ~30° inclusive edge. Mind you I cut extremely dirty cardboard, to the point that the dust and dirt cast off from cutting will make my allergies act up. If you are getting chipping from cardboard then it is either the heat treat on your knife or your sharpening that is causing it, it isn't the steel itself.

 

[Revolverrodger]

Why do you insist on constantly repeating the same false information? INFI is literally one of the toughest stainless steels on the market. You can look up and of the dozens of videos of people absolutely thrashing their Busse knives in INFI and it takes the thrashing as well as a simple carbon steel.

As for S30V chipping on cardboard, I've cut an absurd about of cardboard at work over the year I've been here, and not a single time have I experienced any of my steels chip from cardboard. I've ran S30V from shaving to unable to slice paper, not a single chip. Simple ~30° inclusive edge. Mind you I cut extremely dirty cardboard, to the point that the dust and dirt cast off from cutting will make my allergies act up. If you are getting chipping from cardboard then it is either the heat treat on your knife or your sharpening that is causing it, it isn't the steel itself.

I think the point he was making was that INFI with the factory edge is tough but if you grind it thinner it might not hold up as good

 

[Insipid Moniker]

I think the point he was making was that INFI with the factory edge is tough but if you grind it thinner it might not hold up as good

Rule 1, it's absolutely never worth it to try to decipher the point Gaston is trying to make as it's always based on pure fantasy.

 

[Pilsner]

Rule 1, it's absolutely never worth it to try to decipher the point Gaston is trying to make as it's always based on pure fantasy.

Yes, his posts should come with a [mental] health warning.

 

[ShannonSteelLabs]

Rule 1, it's absolutely never worth it to try to decipher the point Gaston is trying to make as it's always based on pure fantasy.

I second this.
Reading his posts is cringeworthy among other things.

 

[AF]

People are rough on knives.
Thick, hefty blades can have a cool factor.
I'm glad not all knives are pure slicers. That would be boring. Lots of options.

 

[91bravo]

This is because a tradition has developed of testing steels by doing non-knife like tasks (materials harder than wood). The most prominent example of this is INFI (which is better than many CPMs at true knife-like tasks, again nothing harder than maple wood): This is what happens to INFI when it is ground to a convex 32-34 degrees inclusive final, and you lightly chop some maple (below is a comparable -slightly thinner- edge in 5160):

Like many newer steels, they do not tolerate reasonably thin angles (15 dps or less), so that is why they are ground thicker, as the tests that developed them seem to favour edge holding at blunt angles (but often non-impact tasks, though INFI did well at not rolling, even if it warped easily): So gradual abrasion tests and that kind of thing.

This below is how many CPMs typically behave under chopping impact (CPM 3V here being the best, taking 20 plus hits for the apex "lip" seen here). S30V, the worst I have seen, will do this merely slicing 1/8" cardboard (Gerber 70th Mark II), or in single chops in maple(!).

Note how the cheap low-end Chinese 420J is completely indifferent to wood impact, the one short lip area being the result of an accidental twisting motion. Angles were similarly thick: Near 20 dps.

On the other hand, using the same 420J and hitting metal will yield severe edge damage as the apex compresses, while other higher-end steels will fare better... The only problem is that this superior high end steel performance appears while doing completely knife-irrelevant tasks, like cutting into metal, or maybe high abrasion tasks...

So yes, strangely enough, something that holds up better against harder (or in knife-unrelated industrial tests) will do worse, relatively, on more realistically soft mediums, at thinner edge angles, especially if chopping (the apex "lip" appearing easily under nail rubbing). The only way to disguise this is to stay safer on the side of thicker edges: Hence the non-aggressive above 15 dps (30 inclusive) edges, usually an amazing 20-25 dps, that you observed.

Gaston

Nothing harder than Maple wood? You have got to get out more, like a lot more. You say you send out blades to Josh to thin out, but then complain about how the edges roll when you chop into something. Well, there's your problem right there, you're taking the edge down way too thin for the couple of chops that you take on "hard" maple wood. Heaven forbid you chop into some seasoned Hickory, your knives above would break right in two...

 

[ShannonSteelLabs]

Nothing harder than Maple wood? You have got to get out more, like a lot more. You say you send out blades to Josh to thin out, but then complain about how the edges roll when you chop into something. Well, there's your problem right there, you're taking the edge down way too thin for the couple of chops that you take on "hard" maple wood. Heaven forbid you chop into some seasoned Hickory, your knives above would break right in two...

His logic is severely flawed. He is to be ignored.

 

[91bravo]

His logic is severely flawed. He is to be ignored.

Plus, this thread is about slicing, not chopping. Always regurgitating the same misinformation. Clone/Ganzo-biased, INFI rolls when you chop 3 times into Maple, CPM is bad, 420J is the best bull malarkey. I tell you what G Gaston444 , I can send a 3V blade out to a 3rd party tester and you send a 420J blade out to the same tester. Let's see what the results will yield at typical and non-typical knife tasks. Under some REAL knife use! Cardboard, wood, plastic, copper wire, corrugated plastic, etc. And testing beyond just 3 chops into wood.

 

[ShannonSteelLabs]

Plus, this thread is about slicing, not chopping. Always regurgitating the same misinformation. Clone/Ganzo-biased, INFI rolls when you chop 3 times into Maple, CPM is bad, 420J is the best bull malarkey. I tell you what G Gaston444 , I can send a 3V blade out to a 3rd party tester and you send a 420J blade out to the same tester. Let's see what the results will yield at typical and non-typical knife tasks. Under some REAL knife use! Cardboard, wood, plastic, copper wire, corrugated plastic, etc.

I'll make the knife in 3v lol

 

[91bravo]

I'll make the knife in 3v lol

Excellent! I got a round of drinks says that your 3V knife will still be slicing paper way longer than his choice knife. I mean for a whole weekend of testing in the woods, chopping, slicing, building camp fires, food prep, more chopping and more fire building. At the end of a 3 day camping trip, when the dust settles, we'll see which knife is still actually cutting. Have a drink on Gaston! lol

 

[ShannonSteelLabs]

I'll even send 2 identical knives with different HTs. One at max toughness (59-60HRC) and one in modified 61HRC (better edge holding and corrosion resistance, slightly less tough).

 

[dkb45]

I'll even send 2 identical knives with different HTs. One at max toughness (59-60HRC) and one in modified 61HRC (better edge holding and corrosion resistance, slightly less tough).

But how will it slice?

 

[ShannonSteelLabs]

But how will it slice?

Well depends on what we use them for. Should be FFG and have a 0.015- 0.020 thick edge. Or go full convex and go a bit thinner (0.010-0.012).
I typically grind my knives thin as i like them to cut well.

 

[91bravo]

Well depends on what we use them for. Should be FFG and have a 0.015- 0.020 thick edge. Or go full convex and go a bit thinner (0.010-0.012).
I typically grind my knives thin as i like them to cut well.

Will you be at Blade this year? Would love to check out some of your work in person!