Tough Enough?

[WilliamMunny]

Edge retention and toughness are a trade offs in steels. I was cutting off the plastic of some chicken wire today, running my S30V steel down the plastic bouncing into off the wire… and I thought is S30V tough enough for this? Would using it like this chip my knife? Would it chip S110V? Should only Cruwear be used for this type of task? Is this knife abuse and the authorities at Spyderco need to be called?

How do you know your knife is tough enough for a job and your not abusing it looking for trouble?

[Evil D]

This almost depends as much on the edge angle you sharpen at as it does the steel. You can tweak the inclusive edge angle to make it more resilient, and even the toughest steel will see damage from this if the edge is made too thin.

So, it may not be the toughest steel but it can work if you'll work with it.

[Ranger_Ike]

Was their any damage to the blade?

[WilliamMunny]

Was their any damage to the blade?

No not at all and if there was I would just sharpen it out. I generally want a knife I can use (not abuse) and not worry about.

It just made me wonder how tough does a folding blade need to be? Maybe my use case needs a tougher steel. There is just no simple chart on how tough of a steel you need.

Something like below would be great based Larian’s toughness numbers:

1 - Paper
2 - Cardboard
3 - Rope
4 - leather
5 - soft wood
6 - xxxxx
7 - xxxxx
8 - Hard Wood
9 - xxxxx
10 - Light Wire

But while cutting tough material is it better to have a tough blade that won’t chip or a blade with good edge retention so it won’t dull?

I mean what’s the point of having a super steel that will cut paper all day long but will chip on a zip tie? Am I missing something….

[Steeltoez83]

S45vn held up much better in my latest testing than s30v. I was using a mixture of gravel, sand and potting soil underneath builder paper for the testing at 1k edge finish. Cruwear, H1. and s90v I got double the performance than s30v. Now that's controlled testing with no lateral force used in cutting. And I tested s30v 3 separate times.

[WilliamMunny]

S45vn held up much better in my latest testing than s30v. I was using a mixture of gravel, sand and potting soil underneath builder paper for the testing at 1k edge finish. Cruwear, H1. and s90v I got double the performance than s30v. Now that's controlled testing with no lateral force used in cutting. And I tested s30v 3 separate times.

How would you compare Cruwear to S90V? You have a very tough steel vs one with a high edge retention.

[Steeltoez83]

S45vn held up much better in my latest testing than s30v. I was using a mixture of gravel, sand and potting soil underneath builder paper for the testing at 1k edge finish. Cruwear, H1. and s90v I got double the performance than s30v. Now that's controlled testing with no lateral force used in cutting. And I tested s30v 3 separate times.

How would you compare Cruwear to S90V? You have a very tough steel vs one with a high edge retention.

I can only speak to my own testing and the samples im using. S90v and even s110v seem to barely pass early stages, having barely passed my sharpness standards to continue testing. Then it goes 4 more runs without any hiccups. And cutting cleaner at 14 cuts over 4 which was strange but repeating on 3 knives and 2 waves of testing. Cruwear didnt have that anomaly, and gradually dulled what i would call normal. Now im testing around 13 degrees per side and with a 1k edge finish. Now s30v i prefer at a coarse 400 or less finish for general use nothing too taxing. Geometry, edge angle, stones used, cutting parameters, cutting style, cutting conditions, blade shape, even the cutting media all factor into real world perspective.

[Wandering_About]

Geometry matters massively for edge durability. It can equalize steels of greatly different toughness. Of course the way the different edges cut will be quite different. Hardness (aka strength) also matters.

The balance between geometry, hardness, and toughness is what determines how an edge holds up. And, of course how that edge is actually used.

Just looking at toughness won't tell you exactly how an edge will behave.

[Enactive]

For comparing steels, outcomes are only relevant if the geometry, apex, and edge finish are as close to identical as possible.

As pointed out earlier-- geometry and edge finish can sometimes have much bigger influences on cutting characteristics than alloy and heat treat.

[Vaugith]

The balance between geometry, hardness, and toughness is what determines how an edge holds up. [...]
Just looking at toughness won't tell you exactly how an edge will behave.

Exactly this. I was quite surprised to find that rex45, despite it's shockingly low toughness, when I freehand sharpen it and allow a slightly convex bevel can stand up to gouging large chips out of copper and aluminum wire better than many other steels. The hardness difference between rex45s 67hrc and that copper and aluminum is very important! Quite tough yet soft 14c28n and aebl did not pass this same test at all! Hardness + toughness = strength, which is a better measure of overall durability. Quantifying strength is a bit abstract at this point, though.

[RustyIron]

is it better to have a tough blade that won’t chip or a blade with good edge retention so it won’t dull?

That's the burning question that keeps all of us knife users awake at night.
And the burning question that keeps Steel Chefs awake at night is how to cook a batch that does both.

[VooDooChild]

I chipped (deformed) the edge on my saber grind endura 4 the other week by twisting it against the corner of a thick mirror.

[Abyss_Fish]

I avoid metal like the plague, and always triple check what I'm going through before I start stabbin'. Measure twice cut once yeah? otherwise don't think about it much.

For steel preferences in general I preffer steels that are particularly tough or pliable (chip resistance and ease of sharpening) , which is why lc200n is a favorite. When I used to work in a kitchen I cut mountains of cardboard daily, plus the occasional fryer filter sheet removal. And when I bought a wharny s30v delica to replace my vg10 wharny Dfly, I had to re-sharpen it 3x as much because it chipped so easily. Not only that it barely kept a fine edge at all. Since then I won't go near s30v for serious use.

[akapennypincher]

How I decided task v/s tool, is to think on task, v/s tool available. Had I need remove the plastic from Chicken Wise a cheap razor blade, cheap Unility knife would be my choice. Single Edge, so if I hit wire, the razor could be tossed, or the Unility blanced could be snapped off having fresh sharp edge.

People would do good to go to Harbor Fredigt for supply of Single Edge blades, and a few utility knives.

Would rather destroy, bend, brake something under $5.00 v/s Spyderco anything.

[Scandi Grind]

The two above replies reflect my thoughts largely. I don't use a knife for anything that is not knife-like function, and I avoid cutting near anything that can't be, or shouldn't be cut with a knife, glass, metal, stone, etc. If I should need to do anything abusive, I use a disposable blade like a box cutter.

That being said, I have heard of some legitimate use cases where people have to use there knives for borderline abusive tasks for their work, and sometimes a box cutter is not the best tool. Those people need something tough, (and good sharpening skills) and have to balance the many factors involved with an edge to get optimal performance, but that is really all of us, we just all have different use cases, and therefore, different optimal solutions. Unfortunately, each users needs are not pre-definable and each knife's performance is not pre-discernable, so much trial and error is involved to discover the best results for each of us. Course we wouldn't have so much fun perfecting our knives if every knife did exactly what we wanted right out of the box, now would we?

[rooster81]

I can only speak to my own testing and the samples im using. S90v and even s110v seem to barely pass early stages, having barely passed my sharpness standards to continue testing. Then it goes 4 more runs without any hiccups. And cutting cleaner at 14 cuts over 4 which was strange but repeating on 3 knives and 2 waves of testing.

It's possible you had a sharpened burr on the knife that was cutting, then was damaged (resulting in barely passing), then getting knocked off which led to the knife cutting cleaner again.

This type of behavior was documented on the "science of sharp" website.

[Steeltoez83]

I can only speak to my own testing and the samples im using. S90v and even s110v seem to barely pass early stages, having barely passed my sharpness standards to continue testing. Then it goes 4 more runs without any hiccups. And cutting cleaner at 14 cuts over 4 which was strange but repeating on 3 knives and 2 waves of testing.

It's possible you had a sharpened burr on the knife that was cutting, then was damaged (resulting in barely passing), then getting knocked off which led to the knife cutting cleaner again.

This type of behavior was documented on the "science of sharp" website.

I don't do burr based sharpening for testing. I alternate strokes to a specified number. And I would clean the knife everytime the same way before taking cutting measurements. I measure only the apex and its ability to grab and cut an index card against the grain to rule out geometry as much as possible. And if the knife fails first test it wasn't apexed but all 24 samples on this test, 28 samples on previous testing all passed that threshold. I do plan on repeating this test wave in the future but with angle guides to ensure the playing field is even. I have several different test waves I plan on doing with these 24 knives first I know my setup has more holes than swiss cheese in it, but I'm trying to be different from other types of testing we see.

[Doc Dan]

Even a more primitive or "lesser" steel can out perform super steels with the right edge geometry. Of course, all things being equal the super steel will out perform the lesser steel in cutting. Still, it is surprising how much edge geometry matters.

Watch this video: https://youtu.be/peO0akVMNbg