Benchmade CPM-20CV vs S90V

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KingZee

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May 18, 2014
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Hi All,

I've generally used BladeHQ's "steel guide" as a quick reference guide for the different steel qualities. Over the years I've found it to be the most straight forward way to compare two steels when shopping for knives but now I'm questioning that reference.

What got me curious is that I've owned both steels in very different knives (20CV in ZTs and the Nakamura and 940-1 in S90V) and was under the impression, from personal use and the BladeHQ "steel guide" that 20CV is generally a MUCH tougher steel than S90V.

With this knowledge I recently purchased a Blade HQ exclusive Bugout in 20CV (my first bugout) assuming that a "toughness" rating of 6 would make it a better EDC than S90V.

Shortly after this, Benchmade released their 2021 catalog with a couple of pages of steel ratings as well and the strength/toughness rating for 20CV vs S90V are the polar opposite of how Blade HQ has them rated.

I've also pre-ordered the new 2021 carbon Bugout from Benchmade in S90V (I lost my 940-1 recently and purchased this as a replacement) so I'm now VERY curious as to what gives in regards to this difference in toughness rating between Benchmade and Blade HQ. Which do you guys think is the tougher steel in terms of chips on the cutting edge? I know I've chipped S90V and the toughest thing I've cut are regular zip ties. The 20CV blade on the bugout that I recently purchased does seem to me to be a tougher steel in the way that it feels during cutting.
 
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I've been a lurker here for so long that I did not realize I've never actually posted here. So with that, hi everyone! Thanks for all the knowledge here over the years.
 
Benchmade states that they heat treat all their steels "differently" but I don't know enough about that to understand if it would make that much of a difference in toughness vs another steel that they are also heat treating themselves.
 
I've always been very skeptical of Benchmade's steel comparison charts, and this year's seems really bad. I mean they show D2 as having equal edge retention to S90V and CPM154, and better edge retention than M390 and M4. Their chart also shows S45VN and Cru-Wear having the same qualities. If anything the S45VN chart should look a lot more like the S30V chart.

It's a long article, but Larrin did an amazing test comparing various steels. About halfway down, there's a chart comparing edge retention to Rockwell hardness, and below that are a few charts comparing toughness and hardness. Even if you don't read the whole article (definitely read the article at some point though), those charts should help you a lot. https://knifesteelnerds.com/2020/05/01/testing-the-edge-retention-of-48-knife-steels/
 
Those sort of steel ranking charts without any actual measured data points should always be taken with a grain of salt. The BladeHQ one is kinda "meh" in my opinion (I don't agree with all their rankings, but with no hardness data, sure, maybe XHP does have edge retention equal to M390 and S90V), and the Benchmade one is laughable. Ingot D2 has edge retention between M4 and 20CV, and CPM-D2 has massively increased corrosion resistance for the same chemistry? Come on.

A better source would be something like the knifesteelnerds site run by Larrin. There's empirical edge retention (wear resistance on Catra testing) and toughness test data, and even a little for corrosion resistance. If you like more real-world testing go find Ankerson's edge retention on rope tests. Coarse and polished edge results both!

As far as data comparing the two in toughness, Larrin has M390/204P/20CV at ~5 ft-lbs a little under 62 HRC. https://knifesteelnerds.com/2020/05/01/testing-the-edge-retention-of-48-knife-steels/

No data on S90V, unfortunately. The somewhat-similar S110V looks hair lower in toughness than 20CV at ~62.5 HRC. I wouldn't claim anything conclusive about S90V without actual data, but the S110V data does suggest that toughness-wise, it should be in the ballpark of 20CV.

As for why 20CV has seemed so much tougher than S90V for you, could be things other than the steel chemistry... If S90V has been getting chips where 20CV doesn't, maybe the 20CV blade is thicker behind the edge or the edge angle is more obtuse than on the S90V blade. Would they perform more similarly with the same geometry? Or is the S90V heat treated significantly harder?

Edit - Silent H and I are on the same page, but he apparently types faster. :)
 
I would second the suggestion to use the chart that Larrin produced. I would add that I did not see M390 and 20CV, but performance will be similar to CTS-204P.

JonesE
 
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20CV is no tougher than S90V. Edge geometry would make a bigger difference than which one you chose. Heat treatment can make some difference of course. Some people report micro-chipping in new knives before they are sharpened a few times due to overheating in grinding. I wish people wouldn’t trust these steel ranking articles but I have no power over that.
 
Thank you all for the great insight. And a response from the man himself Larrin Larrin . I've reviewed the articles and it makes sense. I guess it's tempting to go off of the simple online guides but they don't mean much in the end.
 
KingZee said:
I guess it's tempting to go off of the simple online guides but they don't mean much in the end.
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It is just difficult to get good accurate data. There is scatter in the test results, and there is some variation in the production. IOW the material composition, heat treat, blade geometry, how the blade is sharpened, all affect performance. I always thought that S90V was a few percent above CPM20 and M390 in edgeholding and similar in toughness, close enough that the average user probably couldn't tell the difference.
 
bdmicarta said:
It is just difficult to get good accurate data. There is scatter in the test results, and there is some variation in the production. IOW the material composition, heat treat, blade geometry, how the blade is sharpened, all affect performance. I always thought that S90V was a few percent above CPM20 and M390 in edgeholding and similar in toughness, close enough that the average user probably couldn't tell the difference.
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Those steel ratings articles aren’t based on any data. They’re completely made up based on perception. 20CV and M390 are hot steels right now so they have high scores regardless of reality.
 
I think someone was very confused putting that Benchmade steel chart together. The more you look at it, the more strange/questionable things you find about it. I wouldn't pay much attention to theirs or the one on BladeHQ. Look for actual testing of the steels, like Larrin does on KnifeSteelNerds.

That all being said, it appears to be a commonly held misconception that 20CV is tough stainless steel. It really isn't, and I think S90V is a better designed steel for balancing wear resistance/toughness while still being reasonably stainless.
 
I find these rankings by companies to be questionable. The profit motivation alone, especially for bigger companies is huge.

Most knife buyers likey don't know much about steels, HT, etc to be able to sniff the BS out, and steel like D2 does hold an edge quite well compared to a lot of steels found on cheap folders or soft kitchen knives...
so perception being reality....D2 looks awesome.

For knife/steel nerds, we know there's a lot more to it.

Steel cost, cost to grind, HT difficulty, different ideas on appropriate RC for desires results, etc. User desires (softer steels might be more desirable because it's easy to sharpen them to a very high degree in a short time....aus-8 being a good example).

I work with people who use edged tools frequently. Not one of them can tell you what steel their pocketknife is made from, even though the blade is marked. I've asked them. It isn't a concern they had when buying, yet they notice my knives stay sharp and theirs are barely sharp enough to cut skin even with significant pressure. One guy's knife was so dull it would need an entire new bevel set to get an edge....it could have been used as a trainer.
 
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