How much does toughness matter?

[rooster81]

I've heard/read people say that if you're not using a knife for high impact (heavy chopping) that toughness doesn't really matter that much. And there's no reason to worry about "low toughness" steels, like maxemet, in a pocket knife.

Then I've read other people say that toughness plays an important role in knife stability and wouldn't even consider steels in the "low toughness" curve because of perceived issues with the edge rolling out or shipping to easily.

What are everyone's thoughts and experiences?

Best.

[Danke]

I'm kinda clumsy. High toughness is prized due to that.

[jwbnyc]

Didn’t TripleB (Deadboxhero) do a video on this?

He totally abused a Maxamet knife.

His conclusion was that it’s still steel, so maybe it’s not as tough but it is still, you know, steel.

I’ll see if I can find the link.

Here is one:

https://youtu.be/q5o532fjdec

Actually, he’s done a bunch of them:

https://youtu.be/KZPKIC8oCbE

And..

https://youtu.be/h9GEjCwQ5B8

One more:

https://youtu.be/AZrmZFCmIAY

Okay, just this one more:

https://youtu.be/WZgOWRgS9xQ

[TkoK83Spy]

I honestly don't pay attention to that aspect in a steel. I've got my Maxamet PM2 on me today, and I would use this knife exactly the same as I would use any of my other knives in 11 other steels I have from Spyderco. I think some people get a little too gassed up on the nerdy side of things, instead of thinking logically about what they actually use the knife for. If you're cutting some cardboard and slicing apples, toughness really doesn't play a factor!

[z1r]

Great question, I know that I value toughness, yet, I don't use my knives as prybars. My EDC consists of a K390 Endela and a ZDP DF2. not sure either are high on the toughness scale but they work for me. I did roll the edge badly on the K390 when I had to improvise and use it as a Kitchen knife on a glass cutting board. It performed like a champ but, as I say, did roll the edge from impacting the glass repeatedly. The Brown Sharpmaker rods quickly took care of the roll but did produce one small chip. that was eliminated after a few sessions on the sharpmaker.

So, while I admit to asking for tougher steels (MagnaCut) I'm not honestly certain I would benefit much from them. I do want the N5 Salt in Magnacut, it would become the knife I'd abuse. Ok, use hard, not necessarily abuse.

[sethwm]

Ok here's my dumb question about this. If I roll my edge, I'm not just going to unroll it. I have to sharpen the roll away just like sharpening a chip away. So why is a roll better than a chip?

[JSumm]

I wonder what people think of when they hear toughness in a knife steel? Strength when prying? Chipping? Rolling?
I think (just guessing) they may be thinking of edge stability. In that case, a steel like LC200N has a very high toughness rating (ability to absorb energy without fracturing), but will roll faster than other steels at the edge because of its lower hardness. A steel like K390 that may not be in the same league of toughness as LC200N, but will hold its edge under stress better than LC200N due to its higher hardness. At least in my experience. The steel composition allows for K390 to achieve a higher HRC. I think toughness plays into edge stability, but it is only one piece of the puzzle. Steel composition, grain structure, HRC are others that play into it.

Anyone interested should really watch Shawn' Houston (Triple Bs) videos. He has some awesome real life testing on some of these steels that shows how far the edge can go.

[JSumm]

Ok here's my dumb question about this. If I roll my edge, I'm not just going to unroll it. I have to sharpen the roll away just like sharpening a chip away. So why is a roll better than a chip?

I have heard this before. I guess on a roll, it is easier to sharpen off in my mind. Think of a thin piece of metal hanging off that you are going to directly apply to the sharpener and grind off. Where as a chip, you will need to sharpen the entire edge and get it back to the deepest part of the chip to have a uniform apex.

Also, if the edge rolls, the steel may be a softer steel that is easier to sharpen away. I don't know if that makes sense, but that is how I see that situation in my head.

[jwbnyc]

Small chips aren’t too big a deal. A chip that goes all the way past the grind line is something else.

[wrdwrght]

I think the answer to the question hinges on what kind of edge-deformation you’re willing to accept. I hate chips, so give me toughness without giving up too much wear-resistance.

[Josh Crutchley]

For what I use a knife for high toughness isn't beneficial.

[Giygas]

For what I use a knife for high toughness isn't beneficial.

This may be true, but it's been my experience that high toughness contributes to significantly less edge damage that can't be removed just by stropping.

I have to assume that would be beneficial in your knife uses.

3v may not have the best edge retention, but a few passes on a strop gets it right back to hair popping.

[Giygas]

Accidental double post

[steelcity16]

I'm all for toughness in folders. Have been since day one. I might be the biggest (and loudest) advocate for 3V and Cruwear in folders on here. Still holding out hope for 3V! Notice the little "3V" on my avatar? It's been there for a few years and staying until we get a 3V folder (aside from the Tuff..)! Delta 3V would make a fantastic folder. A Micarta Endela (one leaf and one wharnie) in Delta 3V is my dream knife!

[metaphoricalsimile]

I want to mirror JSumm in that I think *most* people who talk about valuing toughness in a folder are actually valuing edge stability. Edge stability is a factor of toughness, hardness, and geometry, so you can have steels with great edge stability that are not very tough (many of the very hard tool steels fall into this category) and you can have steels with very poor edge stability that are very tough (think LC200N or H1).

One of the reasons why I dislike H1 is that it doesn't have great edge stability in my experience, even in SE blades. I don't particularly care that the knife will bend before it breaks or will roll before it chips, because a bent knife or a knife with a rolled edge is still a tool that will require significant repair before it is fully useable again, and I find that the H1 edge rolls really easily. I'd rather have an edge that doesn't roll *or* chip easily.

Then you have steels like Cru-wear, CPM-M4, Magnacut, etc. that can both be made quite hard *and* are very tough, and you can do ridiculous things like hammer the blade through a mild steel nail with minimal edge damage.

[Evil D]

I want to mirror JSumm in that I think *most* people who talk about valuing toughness in a folder are actually valuing edge stability. Edge stability is a factor of toughness, hardness, and geometry, so you can have steels with great edge stability that are not very tough (many of the very hard tool steels fall into this category) and you can have steels with very poor edge stability that are very tough (think LC200N or H1).

One of the reasons why I dislike H1 is that it doesn't have great edge stability in my experience, even in SE blades. I don't particularly care that the knife will bend before it breaks or will roll before it chips, because a bent knife or a knife with a rolled edge is still a tool that will require significant repair before it is fully useable again, and I find that the H1 edge rolls really easily. I'd rather have an edge that doesn't roll *or* chip easily.

Then you have steels like Cru-wear, CPM-M4, Magnacut, etc. that can both be made quite hard *and* are very tough, and you can do ridiculous things like hammer the blade through a mild steel nail with minimal edge damage.

This is my basic understanding. I also agree, I want a magical sweet spot between rolling and chipping where a steel just blunts as it dulls and doesn't roll or chip unless really beat on. Much of this can be fine tuned with edge angle changes but assuming I sharpen everything at the same angle, I want the Goldilocks steel that hits that sweet spot. So far this is exactly what I'm seeing from my MagnaCut Mule.

[metaphoricalsimile]

This is my basic understanding. I also agree, I want a magical sweet spot between rolling and chipping where a steel just blunts as it dulls and doesn't roll or chip unless really beat on. Much of this can be fine tuned with edge angle changes but assuming I sharpen everything at the same angle, I want the Goldilocks steel that hits that sweet spot. So far this is exactly what I'm seeing from my MagnaCut Mule.

Yeah it's also a reason why heat treat matters so much, because optimal edge performance isn't just a matter of heat treating for the highest toughness or highest hardness, but there's a balance point where you get the best *edge stability* and it feels like Spyderco has that down to a science.

I think that Spyderco's stainless steels like S30V and 20CV/M390/204P outperform most other brands with the same steel because of this. I've done ridiculous things with my M390 Manix with zero issues with my edge and it is *not* a steel that is known for great toughness.

[Matus]

Also agree with the above. Many seem to confuse toughness (ability to resist shock) with edge stability (basically ability to resist static force). In pocket knives I would take edge stability over toughness 9 times out of 10. In utility knives it depends in what the intended use is.

[skeeg11]

The edge stability of H1 is such that Spyderco doesn't make it in FFG to my recollection whereas even Spyderco 8Cr13Mov FFG is common.

[Evil D]

The edge stability of H1 is such that Spyderco doesn't make it in FFG to my recollection whereas even Spyderco 8Cr13Mov FFG is common.

I believe that's supposedly due to work hardening and the blade grinding process in production, or that's what I remember reading. On the other hand people have had no problem doing regrinds on belt sanders, but I'm sure that's not really the same as a mass production situation.