Steels: Extreme Edge Strength

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Steels: Extreme Edge Strength

Postby The Meat man » Tue Nov 06, 2018 10:04 am

Question: what steel currently used by Spyderco has the highest degree of edge strength or stability? I'm not necessarily talking about "toughness", or the chipping-vs-rolling debate. I'm talking about the ability of an edge to resist any and all forms of deformation, even under extreme abuse.

Since heat treat and geometry play such a big role in this equation, let's stick to Spyderco models.

My question is especially directed to those who have rigorously tested similar models side by side, but anyone with real world experience is welcome to chime in as well.
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Re: Steels: Extreme Edge Strength

Postby tvenuto » Tue Nov 06, 2018 10:14 am

Search “edge stability” and read Larrins article. This question isn’t easily answered, if it was all makers would be using the same steel with the same geometry. Also subjective terms like “extreme abuse” aren’t rigorous enough to comment on. No metal is indestructible, so there is some point where no steel or geometry or heat treat will save you.

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Re: Steels: Extreme Edge Strength

Postby Bodog » Tue Nov 06, 2018 10:28 am

The Meat man wrote:
Tue Nov 06, 2018 10:04 am
Question: what steel currently used by Spyderco has the highest degree of edge strength or stability? I'm not necessarily talking about "toughness", or the chipping-vs-rolling debate. I'm talking about the ability of an edge to resist any and all forms of deformation, even under extreme abuse.

Since heat treat and geometry play such a big role in this equation, let's stick to Spyderco models.

My question is especially directed to those who have rigorously tested similar models side by side, but anyone with real world experience is welcome to chime in as well.
Strength and edge stability are not the same thing. Edge stability is a combination of strength (hardness) and toughness. To have the longest lasting edge, ideally you want the highest toughness and hardness with the highest amount of carbide volume that doesn't detract from the toughness. The highest amount of edge stability doesn't necessarily mean the longest lasting edge, same with having the highest amount of carbide volume.

The two basic competing camps can really be summed up by looking at the two biggest proponents of the camps: Cliff Stamp and Jim Ankerson. One is a huge proponent for edge stability alone, but that denies people the ability to saw cut soft abrasive materials for a long time. The other is a huge proponent of raw carbide volume with high strength, but that denies people the ability of the tool to withstand some abuse.

For everyday use, I'm a proponent of the third camp that marries both of the other two camps, and that (at risk of beating the same tired drum) leads me to enjoy steels like Vanadis 4E and M4, which have high toughness at high hardness with a more than reasonable amount of carbide volume. This idea gives the ability to do both, do some abusive work and saw cut nasty materials for long periods of time without needing to continuously resharpen throughout the task. Other people have competing interests, like corrosion resistance or raw wear resistance or raw toughness. But for me, i like the highest achievable hardness with the highest achievable toughness with the highest achievable amount of wear resistance, as balanced as possible. I carry M4, but would rather carry Vanadis 4E, though rex 45 looks promising if used in a readily available platform that i like. They're all capable of high toughness at high strength with a good amount of hard carbides. There's a reason that most bladesports competitors/makers use either M4 or Vanadis 4E. That's one of the best tests for overall edge retention. I do wish they'd add in long term saw cutting through rope to the competition, but that takes away from the quick excitement they want to generate.

All of that is negated if the wrong profile is used. That's why spyderco tops my list of manufacturers. They do a stellar job of balancing the blade profile to the intended use. It's not always the way I'd personally want it, but compared to other manufacturers, they're way ahead in that category. It is what leads people to believe spyderco nails heat treatments vs others. It's, IMO, not really the heat treatment that people are so impressed with, though spyderco does a great job in that department. It's that the blade profile and steel selection matches their expectations. Other makers routinely fail in that department.
Last edited by Bodog on Tue Nov 06, 2018 10:46 am, edited 1 time in total.
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Re: Steels: Extreme Edge Strength

Postby ferider » Tue Nov 06, 2018 10:45 am

Thanks for putting it like this, Bodog. Being still fairly new to this, I'm learning that I am a proponent of the third camp too.

However, even if restricting the discussion to Spyderco, and to the same Spyderco knife name, geometry can still make a big difference: I feel the edge strength leader in my rotation is the CPM 4V hollow ground Manix 2, followed by the plain Rex M4 Manix 2. Both are supposed to have HRC around 64 (?), but the two different grinds (and in particular the tip) feel different in use.

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Re: Steels: Extreme Edge Strength

Postby Bodog » Tue Nov 06, 2018 11:33 am

.
Last edited by Bodog on Tue Nov 06, 2018 10:35 pm, edited 1 time in total.
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Re: Steels: Extreme Edge Strength

Postby The Meat man » Tue Nov 06, 2018 3:40 pm

tvenuto wrote:
Tue Nov 06, 2018 10:14 am
Search “edge stability” and read Larrins article. This question isn’t easily answered, if it was all makers would be using the same steel with the same geometry. Also subjective terms like “extreme abuse” aren’t rigorous enough to comment on. No metal is indestructible, so there is some point where no steel or geometry or heat treat will save you.

My idea was to compare steels used in Spyderco folding knives against each other.

Out of all the many steel options that Spyderco offers, which one would hold up best to, say, cutting open a tin can? Batoning through brass, aluminum, or even steel? How about twisting the edge in hard plastic?

Ankerson did tests in which he chopped through copper wires with an S110V Military.

Deadboxhero has done extensive testing with a Manix 2 Maxamet and Para 3 REX 45.

As mentioned in this thread, CPM M4 has a great reputation for resisting edge damage.

CPM Cru-wear is supposed to be very tough, but if you use it to cut open a can, would the edge fare better or worse than S110V, M4, etc.?

How about K390?

Again, I'm not looking for wear resistance, but edge strength. A ceramic knife is a lot more wear resistance than S110V but it certainly doesn't have the edge strength of S110V.
- Connor

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Re: Steels: Extreme Edge Strength

Postby 500Nitro » Tue Nov 06, 2018 4:51 pm

"Out of all the many steel options that Spyderco offers, which one would hold up best to, say, cutting open a tin can? Batoning through brass, aluminum, or even steel? How about twisting the edge in hard plastic?"

This is a genuine question

Of the above, only the last one (hard plastic) I would put in the normal use of a knife catergory.

The rest I would put in a knife is not designed fir that and better tools are available.

Yes, I know we all get it make our knives do more than they were designed for (in my case cutting heads off animals through the spine) but IMHO the above examples goes into the abuse level.

So, the genuine question is, why do people use (and IMO Abuse) their knives like this - cutting tin cans and steel being good examples ?

TIA
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Re: Steels: Extreme Edge Strength

Postby Surfingringo » Tue Nov 06, 2018 4:57 pm

Of all the steels I have used, I would say that M4 best meets your criteria.

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Re: Steels: Extreme Edge Strength

Postby The Meat man » Tue Nov 06, 2018 5:18 pm

500Nitro wrote:
Tue Nov 06, 2018 4:51 pm
"Out of all the many steel options that Spyderco offers, which one would hold up best to, say, cutting open a tin can? Batoning through brass, aluminum, or even steel? How about twisting the edge in hard plastic?"

This is a genuine question

Of the above, only the last one (hard plastic) I would put in the normal use of a knife catergory.

The rest I would put in a knife is not designed fir that and better tools are available.

Yes, I know we all get it make our knives do more than they were designed for (in my case cutting heads off animals through the spine) but IMHO the above examples goes into the abuse level.

So, the genuine question is, why do people use (and IMO Abuse) their knives like this - cutting tin cans and steel being good examples ?

TIA

I agree that it's abuse. I'm just interested in seeing how far these things can be pushed. :)
- Connor

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Re: Steels: Extreme Edge Strength

Postby 500Nitro » Tue Nov 06, 2018 5:23 pm

Meat man

One form of 'abuse' is the one I mentioned,
jamming the knife blade between 2 vertebrae of a large animal to pry them open enough to cut everything soft. I reckon Some of those bones are harder than steel.
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Re: Steels: Extreme Edge Strength

Postby Tdog » Tue Nov 06, 2018 5:37 pm

Surfingringo wrote:
Tue Nov 06, 2018 4:57 pm
Of all the steels I have used, I would say that M4 best meets your criteria.
My knives don't get a lot of "hard use" but I was going say M4 as well. Knowing Gayle Bradley uses this for competition cutting says a lot.

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Re: Steels: Extreme Edge Strength

Postby tvenuto » Tue Nov 06, 2018 6:48 pm

The Meat man wrote:
Tue Nov 06, 2018 3:40 pm

My idea was to compare steels used in Spyderco folding knives against each other.
I understood, I was just saying that if there was some sort of ultimate optimum steel which would resist all edge deformation, which would basically be blunting, then everyone would already be using it for knives, since it would hold the edge the best.
The Meat man wrote:
Tue Nov 06, 2018 3:40 pm
Out of all the many steel options that Spyderco offers, which one would hold up best to, say, cutting open a tin can? Batoning through brass, aluminum, or even steel? How about twisting the edge in hard plastic?

Ankerson did tests in which he chopped through copper wires with an S110V Military.

Deadboxhero has done extensive testing with a Manix 2 Maxamet and Para 3 REX 45.

As mentioned in this thread, CPM M4 has a great reputation for resisting edge damage.

CPM Cru-wear is supposed to be very tough, but if you use it to cut open a can, would the edge fare better or worse than S110V, M4, etc.?

How about K390?

Again, I'm not looking for wear resistance, but edge strength. A ceramic knife is a lot more wear resistance than S110V but it certainly doesn't have the edge strength of S110V.
In engineering, you have what we call "Factor of Safety." That is, how "overbuilt" is something? If it has a SF of 2, then the item in question is designed to actually withstand twice the designed load.

As an example, the little tool that comes with your IKEA furniture has a very low safety factor. If you slip once you're likely to damage it, but that's OK because you're probably going to only use it once. A standard screwdriver has a massive safety factor. The loads to put in screws are relatively low, but they don't want it breaking when used for prying or anything else.

So, if your tool has a high factor of safety, it'll be less likely to fail under loads that are higher than intended. However, not failing is not failing. If you cut through your can with S110V and M4, and K390, and none of them exhibit damage, then all you've learned is that they all have a safety factor higher than needed for that particular task (and the way it was done that particular time). You'd have to keep upping the test repeatedly until one or the other dropped away, but even then you'd still only have a very rough idea of which was stronger, since each experiment was fraught with potential errors (such as the person twisting more in one cut, or hitting harder with the baton).

The is the purpose of CATRA testing, but in the realm of wear resistance. It cuts while trying to eliminate sources of human error.

So, again: when the question is formulated this way it will be very difficult to arrive at an answer. This is especially true when the anecdotes you'll get are not from people who have inspected the edge closely after each "hard use incident." M4 has been mentioned as a top contender, but perhaps it just gets damaged/deformed in such a way that minimizes the reduction in cutting performance, as opposed to not being damaged/deformed at all (which was the criteria you put forth).

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Re: Steels: Extreme Edge Strength

Postby Chris_P_Bacon » Tue Nov 06, 2018 7:45 pm

M4 Vs Rex 45
Granted not a controlled environment that can be called scientific by any means. But, it's about as good as we're going to get until some propeller head does it in a lab and publishes the results.

Should we form opinions based off our own tests like this?
That's up to each person to decide. I'd say it's better than nothing.

Is it abuse? Once you own it, you can do what you like with it. As long as you aren't being a weasel and sending it back to the manufacturer seeking replacements.

BBB has often said buy your own and do your own testing/abusing. You can learn a lot that way.
If you do, please video and post. I dig watching people testing knives, especially like this. :D

https://www.youtube.com/watch?v=WOpu13O_OFE

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Re: Steels: Extreme Edge Strength

Postby Chumango » Tue Nov 06, 2018 8:25 pm

Video probably tests hardness more than toughness.

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Re: Steels: Extreme Edge Strength

Postby The Meat man » Tue Nov 06, 2018 8:31 pm

That video is a great example of what I'm talking about. The REX 45 edge seems to be a good deal stronger than the M4.
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Re: Steels: Extreme Edge Strength

Postby JackofAllBlades » Tue Nov 06, 2018 9:18 pm

Dying to see this type of testing with Cruwear. Even if it fairs worse than rex 45 or m4 in edge stability, id still love it for the balance of qualites like corrosion resistance and sharpenability. Also, Cruwear polishes VERY easy in my experience.

Bring on the Cru-wear tests!!!

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Re: Steels: Extreme Edge Strength

Postby tvenuto » Wed Nov 07, 2018 6:27 am

Bodog wrote:
Tue Nov 06, 2018 11:33 am
It's kind of funny. The steels that both Jim Ankerson and Cliff Stamp advocate for are basically the opposite of what spyderco tapped them for. Stamp wants high edge stability, yet Stamp said that Maxamet is a good choice for knives even though Maxamet is kind of contrary to his normal position. Spyderco went with Maxamet and people tend to love it even though it's basically the opposite of what Stamp generally advocates for.

Ankerson usually says that raw carbide volume coupled with high hardness is what he likes, though the knife with his name attached shows otherwise. Spyderco ran with 4V, regardless of Ankerson's previous statements that 10V or whatever would be more than adequate. I find that to be dishonest from him as he's never really advocated for 4V. Someone else, likely in the spyderco company, suggested they'd only go with his idea if it was something with 4V in it and Ankerson acquiesced. And now we have a knife with his name on it with a steel he's never really advocated for.

It's funny to me that both competing camps find equity in the steels the other has complained about. Spyderco has found a way to marry them whether they like it or not. I do find that quite humorous. It also impresses me that spyderco found a balance regardless if the competing camps like it or not, and that's by attaching their names to basically the opposite steels for which they normally advocate. I don't know if that was intentional by spyderco, but it sure seems like it. Regardless, it was a good move pitting the two camps against each other by producing knives with steels that are opposed to each other with the leaders of the two camps attached to steels opposed to their normal statements.

I say good on spyderco for their mythbusting/camp busting efforts.
I kind of took Cliff's original recommendation of Maxamet to be like saying: "well fine, if you're going to go super high carbide volume, then may as well try this one."

As I've mentioned to you previously, I've also noticed...inconsistencies...in Ankerson's statements/testing.

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Re: Steels: Extreme Edge Strength

Postby JD Spydo » Thu Nov 08, 2018 7:44 am

I've done a lot of thinking about this subject of "Edge Retention and overall Edge Strength". To me it's really a wide open subject that depends of many variables. First of all you have your heat treatment. Take D-2 blade steel for instance>> I've been told that there are very few bladesmiths out there that are really good at heat treating D-2. And I'm sure that D-2 isn't the only blade steel that is difficult to heat treat properly.

Also when you consider the maker of a certain steel. Take Crucible for instance. They make their own version of D-2. I'm quite confident that not all major steel producers are not the same with their quality control. Not to mention that every steel producer I'm sure has their own protocol on steel production.

I say all of that wondering if the steel producer themselves might play a more vital role than does a specific alloy :confused: ?? Personally I've had great luck with Crucible, Carpenter and Bohler Uddeholm. Now some steels like ZDP-189 has only one producer (Hitachi) whereas D-2 probably has a dozen producers. Just a few things to consider.

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Re: Steels: Extreme Edge Strength

Postby Baron Mind » Fri Nov 09, 2018 10:47 am

Bodog wrote:
Tue Nov 06, 2018 10:28 am
The Meat man wrote:
Tue Nov 06, 2018 10:04 am
Question: what steel currently used by Spyderco has the highest degree of edge strength or stability? I'm not necessarily talking about "toughness", or the chipping-vs-rolling debate. I'm talking about the ability of an edge to resist any and all forms of deformation, even under extreme abuse.

Since heat treat and geometry play such a big role in this equation, let's stick to Spyderco models.

My question is especially directed to those who have rigorously tested similar models side by side, but anyone with real world experience is welcome to chime in as well.
Strength and edge stability are not the same thing. Edge stability is a combination of strength (hardness) and toughness. To have the longest lasting edge, ideally you want the highest toughness and hardness with the highest amount of carbide volume that doesn't detract from the toughness. The highest amount of edge stability doesn't necessarily mean the longest lasting edge, same with having the highest amount of carbide volume.

The two basic competing camps can really be summed up by looking at the two biggest proponents of the camps: Cliff Stamp and Jim Ankerson. One is a huge proponent for edge stability alone, but that denies people the ability to saw cut soft abrasive materials for a long time. The other is a huge proponent of raw carbide volume with high strength, but that denies people the ability of the tool to withstand some abuse.

For everyday use, I'm a proponent of the third camp that marries both of the other two camps, and that (at risk of beating the same tired drum) leads me to enjoy steels like Vanadis 4E and M4, which have high toughness at high hardness with a more than reasonable amount of carbide volume. This idea gives the ability to do both, do some abusive work and saw cut nasty materials for long periods of time without needing to continuously resharpen throughout the task. Other people have competing interests, like corrosion resistance or raw wear resistance or raw toughness. But for me, i like the highest achievable hardness with the highest achievable toughness with the highest achievable amount of wear resistance, as balanced as possible. I carry M4, but would rather carry Vanadis 4E, though rex 45 looks promising if used in a readily available platform that i like. They're all capable of high toughness at high strength with a good amount of hard carbides. There's a reason that most bladesports competitors/makers use either M4 or Vanadis 4E. That's one of the best tests for overall edge retention. I do wish they'd add in long term saw cutting through rope to the competition, but that takes away from the quick excitement they want to generate.

All of that is negated if the wrong profile is used. That's why spyderco tops my list of manufacturers. They do a stellar job of balancing the blade profile to the intended use. It's not always the way I'd personally want it, but compared to other manufacturers, they're way ahead in that category. It is what leads people to believe spyderco nails heat treatments vs others. It's, IMO, not really the heat treatment that people are so impressed with, though spyderco does a great job in that department. It's that the blade profile and steel selection matches their expectations. Other makers routinely fail in that department.
Third camp is the best camp. High hardness, medium carbide volume. 3v, 4v, Cruwear... where you draw the line is debatable, but you get the idea. I believe Big Brown Bear calls this the Goldilocks Zone.

I was being tongue in cheek about them being "the best" I think 52100 and s110v are great steels as well, but if I could only have one it would be from the third category.

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Re: Steels: Extreme Edge Strength

Postby SpyderEdgeForever » Fri Nov 09, 2018 7:40 pm

There must be some way to make a steel that has the edge holding power of 52100 and the elastic power of a polymer, and the toughness and strength of H1 stainless nitrogen steel. There has to be. And that is self-healing. Spyderco can do this, I know they can.


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