CPM-20CV: Tough Enough?

Stephen W Huyssoon

Stephen W Huyssoon

Joined
May 31, 2018
Messages
227
So, I have a new knife, a very well made and strong folder in CPM-20CV, U.S.A. made, and I have been wondering whether I should have configured it with CPM-M4.

1. I am concerned that maybe the CPM-20CV blade will chip or even break. Does anyone have some experience with this issue, good or bad?

2. Coatings on a CPM-M4 blade: Effective? Wears off? Does M4 rust easily?

Thanks and happy turkey day.
 
I wouldn't worry about 20CV chipping on a folder. It's a great blade steel. M4 rusts like any other carbon steel, but if you don't want a patina, I've found it is easily kept at bay with the occasional oiling. You could always force a patina or let it form naturally. I think they look great that way. :thumbsup:
 
I've used M390 on some small/medium fixed blades without any problems, I like M4 as well, I don't oil it and haven't a any corrosion issues however, that's living in Utah/Arizona the last 8 years
 
Pretty much above. M4 is a supposed to be a lot tougher than 20CV at commonly used manufacturer harnesses but it will stain reasonably easy. Not as easy as a simple carbon steel but it's fairly low on the stain resistance. Edge retention of both is comparable for with toughness and stain resistance being the bigger differences. At least from a general perspective. You can go into benchmade's custom shop and in the knife steel selector for griptillian (because it allows for the most steel choices) there are the rough guidelines that they use for getting that info that should include comparison against those steels at the heat treats they use as the differences can vary from manufcaturers depending on the heat treat.

As far as coatings, they all wear but different coatings wear at different rates and all that. DLC is the best I've seen and then paint, powder coats, and the ruffle stuff from ontario and others isn't all that great. Really, most coatings last well unless you're chopping, from my experience. Maybe if you cut a lot of abrasive material like cardboard but most of my carbon steel blades that lose coating are big blades as I choose stainless for shorter blades, most of the time. Or keep them well oiled in the case of GEC's or the like.

I like patina so I prefer CPM M4 but 20CV/M390 (same thing from different manufacturers) is considered by many to be the perfect EDC steel, or right the heck up there anyway, if it fits into your budget.
 
I like the edge holding of m4 a lot, but working near the ocean, I developed rust spots on my blade , even with nightly rinsing and drying the blade and weekly oiling. A couple of rust spots are fairly deep because they have been hard to remove. I hate to work harder than that to prevent rust.Now I stick with stainless for outdoor work.
The 20 cv is very good with edge holding and corrosion resistance.
 
I thank all of you for your replies.

whp said:
I like the edge holding of m4 a lot, but working near the ocean, I developed rust spots on my blade , even with nightly rinsing and drying the blade and weekly oiling. A couple of rust spots are fairly deep because they have been hard to remove. I hate to work harder than that to prevent rust.Now I stick with stainless for outdoor work.
The 20 cv is very good with edge holding and corrosion resistance.
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Let me ask you, whp, does your M4 blade have a coating?

halden.doerge said:
What are you planning on doing with this folder that you are afraid will chip it out?
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Cutting things.

Dangerously said:
Tough enough for what? And if the geometry is chosen to match the steel and heat treat, then you don’t need to worry about chipping or breaking on lots of tasks.

My experience with 20cv is that it’s great. Easier to sharpen than I expected, and holds up well on wood.
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So, you have used 20CV and it hasn't chipped or broke and you had to alter the geometry of the edge?

BilboBaggins said:
I wouldn't worry about 20CV chipping on a folder. It's a great blade steel. M4 rusts like any other carbon steel, but if you don't want a patina, I've found it is easily kept at bay with the occasional oiling. You could always force a patina or let it form naturally. I think they look great that way. :thumbsup:
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This is what I want to hear. Because I have already ordered another excellent knife in 20CV.
 
Hinderer used it exclusively on his knives for many years and I don't remember any problems.
Mine certainly didn't have any
 
Given the following conditions:
- The knife isn't hardened to something like 64 HRC
- "Cutting things" doesn't include hacking your knife against bricks

Then you're set.

As a bit of useless anecdotal evidence, I was using a Spyderco Southard (CTS-204P, equivalent to M390 and 20CP) to cut a zip-tie that was affixed to a steel pipe fence, used too much force... and hit the fence hard enough to cause it to resonate loudly. After I worked up enough courage to inspect the blade of my nearly brand-new knife and face the shame of having ruined something I could barely afford, I found no damage to the edge. Not even a roll. You'll be okay.
 
I've had more chipping with M390/20CV than with lower alloy content stainless like 154cm/S30V, even while cutting cardboard. They're generally small chips, but frustrating to have to fix nonetheless.
 
marrenmiller said:
I've had more chipping with M390/20CV than with lower alloy content stainless like 154cm/S30V, even while cutting cardboard. They're generally small chips, but frustrating to have to fix nonetheless.
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... How did you chip M390 with cardboard?

Like, I understand that you legitimately might not have a better answer than just "I did", but... I've used a wide variety of steels on an immeasurable amount of cardboard and never had it chip aside from a couple cheap utility razor blades. Rolled edges, sure, but I'd only lost bits of proper folding knife edge to solid wood, poor sharpening, and hard flooring.

I assure you I'm not trying to question the validity of your statement. It's just so far out of sync with my own personal experiences that I can only assume you have cut magnitudes more cardboard than I have - and I worked retail for nearly a decade. Maybe I've just been super lucky?
 
Rykjeklut said:
A question for you older, more experienced gentlemen... what did you do 20-30-40 years ago before all the supersteels of today were around? Buy a new knife every time you made a cut?
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:rolleyes: Yes, yes we did. Naturally.

It’s a knife forum, we like to discuss steel. We could sit around discussing the merits of 420HC and denigrating all these new-fangled super steels if you like? :confused:
 
Rykjeklut said:
A question for you older, more experienced gentlemen... what did you do 20-30-40 years ago before all the supersteels of today were around? Buy a new knife every time you made a cut?
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1095 and 440c steels are pretty decent
 
Rykjeklut said:
A question for you older, more experienced gentlemen... what did you do 20-30-40 years ago before all the supersteels of today were around? Buy a new knife every time you made a cut?
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40 years ago would be 1978, the year I graduated high school. I might have owned a knife then, but maybe not. I didn't know how to sharpen. As you said, there was no 20CV then. Really, then, was chipping a problem then? What are you trying to say?
 
It was an attempt at humour and sarcasm, both of which are tricky via text, aimed at the question of whether 20CV was though enough for cutting things.

I don't know. There was no offense meant, just a bit jaded about all this steel talk and hyping.
 
Comeuppance said:
... How did you chip M390 with cardboard?

Like, I understand that you legitimately might not have a better answer than just "I did", but... I've used a wide variety of steels on an immeasurable amount of cardboard and never had it chip aside from a couple cheap utility razor blades. Rolled edges, sure, but I'd only lost bits of proper folding knife edge to solid wood, poor sharpening, and hard flooring.

I assure you I'm not trying to question the validity of your statement. It's just so far out of sync with my own personal experiences that I can only assume you have cut magnitudes more cardboard than I have - and I worked retail for nearly a decade. Maybe I've just been super lucky?
Click to expand...
I haven't experienced chipping from cardboard either, with any steel, much less these so called super steels.
 
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