How tough CPM-3V really is?

Status
Not open for further replies.
D3V from Carothers Performance Knives is great steel. The 'D' stands for their Delta Protocol heat treat. I use my DEK1 in D3V steel all the time and I haven't seen any chipping. I've even smacked the edge against a steel bar accidently and there was no chip or roll on the edge. I held my breathe while I looked at it but breathed easy when all I could see was a flake of black paint from the steel bar.

CPK Pix-7a.jpg
 
000Robert said:
D3V from Carothers Performance Knives is great steel. The 'D' stands for their Delta Protocol heat treat. I use my DEK1 in D3V steel all the time and I haven't seen any chipping. I've even smacked the edge against a steel bar accidently and there was no chip or roll on the edge. I held my breathe while I looked at it but breathed easy when all I could see was a flake of black paint from the steel bar.

View attachment 2073902
Click to expand...
In my part of the world CPK is unavaliable and if you want to import it - it's crazy expensive.

So, here if you want crazy toughness options are these, from cheapest to most expensive:
Hultafors Heavy Duty
Mora Robust
Terava - their 80CrV2 is crazy tough
ESEE
ANV - apparently does Sleipner good
TOPS

None of these will quite match the combination that delta 3V has (stain resistance, edge retention and toughness). But, that is what we have.

European makers are mostly making knives that are very balanced. Meaning covering edge retention, stain resistance and toughness without any of it being extreme. So they use steels like Sleipner, Niolox and so on. And when it comes to carbon steels - 80CrV2 sees more use lately. And the Elmax of so called "super steels" - TRC is using it a lot, Fallkniven started to use it too.
 
shane45-1911 said:
Not necessarily.

That's like saying that a scalpel that chipped should have had a more thickness behind the edge. I'm pretty sure the surgeon doesn't want a sharpened pry bar.

Some people want the thinnest grind possible (while not losing significant edge retention) for slicing. Yes, you have to be careful what you are slicing into (hidden dangers), but I would rarely if ever sacrifice slicing ability for more robust edge retention achieved by a more obtuse edge bevel ("survival" knives being the notable exception).

Yes, it's a compromise but some like their knives slicey and I would rather lose a point or two of HRC to gain some toughness in order to have a durable thin edge, rather than changing my edge geometry and compromise slicing ability.

YMMV.
Click to expand...
Too often, folks neglect to keep things simple, if you chip and roll your edge for any steel, the edge is too thin for what its being used for. If it isn't cutting the way one likes they can go thinner. It's an inverse relationship and there is no one size fits all.

Geometry is number one, can't compare steels and heat treatments till geometry is ruled out.
 
DeadboxHero said:
Geometry is number one, can't compare steels and heat treatments till geometry is ruled out.
Click to expand...

We'll agree to disagree.

I can do things with an optimal heat treatment and less-than-ideal edge geometry, that I cannot do if the HT is crap.

Proper heat treatment allows far more forgiveness, than edge geometry. Example, I could cut down a tree (theoretically, and quite slowly) with a scalpel, if the heat treatment was good. I could NOT cut down a tree even with the most optimal edge geometry (with any knife) if the HT fails on me and my blade edge falls apart, however.

By your statement, we all should be perfectly equipped with Pakistani knives with their non-existent heat treatment, as long as the edge geometry is suitable for the task. And that's simply not the way it works....

I do concede that the equation does include a proper balance of good HT and edge geometry to suit the task at hand.

However, in my 40 years of knife usage, I still maintain that:
Proper heat treatment > edge geometry > steel type
 
Last edited:
shane45-1911 said:
We'll agree to disagree.

I can do things with an optimal heat treatment and less-than-ideal edge geometry, that I cannot do if the HT is crap.

Proper heat treatment allows far more forgiveness, than edge geometry. Example, I could cut down a tree (theoretically, and quite slowly) with a scalpel, if the heat treatment was good. I could NOT cut down a tree even with the most optimal edge geometry if the HT fails on me and my blade edge falls apart, however.

By your statement, we all should be perfectly equipped with non-existent heat treatment Pakistani knives as long as the edge geometry is good. And that's simply not the way it works....

I concede that the equation does include a proper balance of HT and edge geometry to suit the task at hand.
Click to expand...
I concur. Case in point, Spyderco Gayle Bradley. CPM-M4, hollow ground fairly thin. Yet in 8.5 years of ownership, it has never chipped. I've hit staples in cardboard, cut all sorts of stuff.

There are just so many factors that go into it. What you are doing, heat treatment, edge geometry etc. I have a Demko ad20.5 in CPM-3V, and while I haven't done much heavy duty or extensive cutting with it (too new and I'm not doing as much as I once did) but it has seen no issues. The heat treatment seems good as edge retention has been good, but it also is a bit of a thickboy (for me at least I'm not into medford overbuilt type stuff) but still.

Anyway, as Shane said above, optimal heat treatment is going to be a big factor. This is why stuff like chinese d2 often doesn't have the same qualities as American made d2.
 
hugofeynman said:
Once, Fredrik Haakonsen told me something like this: “if there where a pm steel tougher than A8mod (heat treated by him) or other clean cold work steel optimized for toughness, I would be using it”. Until today, he still uses A8mod in his survival/hard use knives. From that moment, I stopped looking at pm steels (I’m obsessed with toughness, don’t care for “wear resistance” or stainless).
Click to expand...
Ah come on. You know ztuff beats A8 and it’s pm steel! 😁
 
Carothers heat treat is the best on 3v, but Buck has done a decent job with it on their knives in 3v....
 
Some manufacturers overheat their edges during the grind/sharpening. Yeah, the stock may feel cool to the touch, but the thin edge will heat up much quicker than your fingers on the spine can detect.

A garbage edge may turn into magic after you show it some love.

Also, i tend to see factory 1095 ran much softer than 3v
 
wulfns said:
Also, i tend to see factory 1095 ran much softer than 3v
Click to expand...
That is an important point. One of the advantages of modern steels is that they are tougher at higher hardnesses than the simple carbons, so a lot of makers leave them higher to get better wear resistance. The blade in your hand might not be particularly tougher than the one you bought 20 years ago, but other characteristics will be better.

The knife industry has been through this many times. It is and probably always will be possible to break knives no matter how much hype the steel they are made from has gotten. Somewhere someone probably broke a tank today. The key is asking yourself if you'll ever actually go that far with your knife, and balance that against all the stuff you'll actually do with it that will suffer if you chase ultimate toughness.
 
One thing I notice in the graphs is that many of the steels are given for a range of hardness and these some of these ranges are limited. For instance 3V is given down to Rc58 but 80CrV2 is only given down to Rc60. We would normally think of S3V in a big outdoors blade which would also be run at lower hardness, what other steels could have equal or better toughness at similar hardness?

When talking about edge chipping I wonder how much this is affected by hardness and how much this is affected by hardness. A harder steel will resist chipping even if that steel has lower toughness. Toughness doesn't enter into the comparison until stresses on the blade exceed the strength limit of the steel, and hard steels have higher strength limit than less hard steels.
 
shane45-1911 said:
We'll agree to disagree.

I can do things with an optimal heat treatment and less-than-ideal edge geometry, that I cannot do if the HT is crap.

Proper heat treatment allows far more forgiveness, than edge geometry. Example, I could cut down a tree (theoretically, and quite slowly) with a scalpel, if the heat treatment was good. I could NOT cut down a tree even with the most optimal edge geometry (with any knife) if the HT fails on me and my blade edge falls apart, however.

By your statement, we all should be perfectly equipped with Pakistani knives with their non-existent heat treatment, as long as the edge geometry is suitable for the task. And that's simply not the way it works....

I do concede that the equation does include a proper balance of good HT and edge geometry to suit the task at hand.

However, in my 40 years of knife usage, I still maintain that:
Proper heat treatment > edge geometry > steel type
Click to expand...
Well, we can't heat treat a wrench into a screwdriver any more than we can a scalpel to an axe.

I'm a big fan of heat treatment so I'm certainly playing devil's advocate here but when someone chips an edge or inversely its not cutting well, its not a direct sign of ht and steel until geometry and use is ruled out first.
 
A lot of people mistake rolling/denting for chipping. The former can often be a sign that the steel is just too soft.
 
chipping-resistance-vs-edge-angle.jpg

Some fantastic testing Larrin did on edge impact toughness.

Same steel, same HT and AEB-L is one of the toughest knife steels and here you can see the limits with impact toughness with different edge geometry.

A true, flat 15° per side without convex will be significantly more delicate than a flat 25° per side.


Yet, in a lot of testing and anecdotal accounts we see on the forums and other social media no one is talking about what edge angle they are using.
 
bdmicarta said:
One thing I notice in the graphs is that many of the steels are given for a range of hardness and these some of these ranges are limited. For instance 3V is given down to Rc58 but 80CrV2 is only given down to Rc60. We would normally think of S3V in a big outdoors blade which would also be run at lower hardness, what other steels could have equal or better toughness at similar hardness?

When talking about edge chipping I wonder how much this is affected by hardness and how much this is affected by hardness. A harder steel will resist chipping even if that steel has lower toughness. Toughness doesn't enter into the comparison until stresses on the blade exceed the strength limit of the steel, and hard steels have higher strength limit than less hard steels.
Click to expand...
The tables from Larrin shows only what he has personal data for. Each dot is a sample, hence some steel is only 1 dot, because he had only one sample to test on. His samples are made to the same dimensions then heat treated accordingly to the best of his knowledge to make the test to be the most indifference as possible.

By the way, do you account in the chipping due to brittleness? Toughness is more or less the everything up to the breaking point, unlike strength which is usually the permanent deforming point. Softer steels might still have the same toughness as harder steel, they deform before they break, like edge rolling, which is not a desired property for knife. At lower toughness, it means they will chip more often than they deform, as in brittle.

3V probably having the yield point close to the breaking point while withstanding long strain, which makes it feels more chippy. Also, the main selling point of 3V is not just toughness, but also wear resistance, which is quite high for its toughness.
 
shane45-1911 said:
Quality heat treatment > steel type.

Any steel with inconsistent/inferior heat treatment will under-perform.

3V is amazing when done correctly.
Click to expand...
100 X This. There are a lot of steels that I prefer buying depending more on who is doing the work than what the steel is.
 
I mean, kinda sad that 3V exists for so long and only few makers are able to heat treat it right.

So in a nutshell - if you aim for toughness you're getting tougher knife buying well done 1095 than "budget" 3V...
 
LostCause said:
So in a nutshell - if you aim for toughness you're getting tougher knife buying well done 1095 than "budget" 3V...
Click to expand...

Basically, yes. Although 1095 might not be the best example to use. :)

Said another way (and why I still maintain HT is more important than edge geometry), I can still cut with proper HT and less-than-ideal edge geometry - just not as efficiently.
 
Status
Not open for further replies.
Back
Top