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Can You Even Tell the Difference?

I have seen a common comment on knife forums and on my YouTube videos. It seems to be one of those statements that different people unintentionally copy from someone else. Everyone seems to think they thought of it on their own. It has a lot of variations but boils down to one statement: “People can’t tell the difference between knife steels anyway.”

The reason why the variations matter is because people are making different points when saying it. I believe that these kinds of statements started out as a criticism of certain knife buyers: “You never use your knives so you wouldn’t know what knife steel was even used.”

Another variation is to say that “premium” knife steels are all good and the differences between them are so small that nitpicking about which one is used is unimportant.

But I have seen people take this statement to the extreme and claim that there actually is no real difference between steels at all.

Edge Retention

This discussion can go a lot of different ways so let’s start with one of knife enthusiasts favorite topics – edge retention. If we look at the CATRA chart for different steels, for example:

Those tests were all done with identical edge geometry. You can also see the approximate effect of hardness by looking at the dashed diagonal lines (some steels were also tested at multiple hardness levels). You will notice that there are steels that tested under 300 mm of cardstock cut, all the way up to 1150 mm. That is a huge range. If we compared 8670 and Rex 121 in virtually any side by side slicing test with identical edge geometry I find it hard to believe that someone wouldn’t see the difference.

The Car Analogy – Commuter vs Soccer Parent

But most knife users are not doing side by side tests to compare steels. And that’s fine. When we cut random things, a random amount per day (or week, or month) it is very difficult to know how much cutting one knife did vs another. It’s like if I was comparing the gas mileage of two cars. If I was a commuter making the same drive to and from work five days a week and not driving my car at any other time, the comparison would be obvious. I may not even need to run any numbers to know if one car had only 20% better gas mileage, much less 100% better. However, if it is a family car, being driven around for different kids activities, sometimes going to the store, sometimes sitting for two days, etc. it would be very difficult to be able to tell if one car had 20% better gas mileage than another. The usage would be too variable. That doesn’t mean that I’m not actually getting better gas mileage out of one of the cars. It just means that I would have to look at some numbers to find out. (Where this analogy partially falls down is that our cars do show us the average MPG where the knife does not have a record of how much it cuts in between resharpening).

The point I am making is that just because someone couldn’t tell that there was a difference doesn’t mean that there wasn’t a difference. A knife can be cutting longer even if you didn’t notice. That also doesn’t mean that you have to buy a new knife any time there is a new knife steel. Just like you don’t need to buy a new Honda Accord just because they redesigned it for 2026. Engineers make improvements to products, and progress will continue.

Differences within Category

However, I can also agree that there is a level of nitpicking that can be unproductive among knife enthusiasts. This is especially true when people are arguing about minute differences between steels within the same “category.” For example, comparing the edge retention of S30V and M390. The differences are going to be small. There would be little difference to select one knife over another if the main goal was to achieve a small percentage increase in edge retention by selecting M390. That is partially ignoring other tradeoffs between them, of course. But they are both powder metallurgy stainless steels with 4% vanadium with similar edge retention. They are in the same “category.” Sometimes there are improvements with new steels within a given category, or at least a different set of tradeoffs that could be more desirable for different applications. But usually we are not talking about massive differences.

If, however, we are talking about 8670 vs S125V, yes, these steels are massively different. Simple low alloy steels used by forging bladesmiths vs a high wear resistance stainless steel by a stock removal maker would not be the same. These are totally different categories and will behave very differently in many ways. Calling these differences indecipherable would be nonsensical.

Edge Geometry

Steel is only one part of the equation. Every knife buyer knows that different knives can perform very differently even in the same steel. Even if they had identical heat treatments. Because edge geometry is the most important factor for knife performance.

When pure cutting performance is desired, thin, acute edges are king. It makes an even bigger difference than the steel or heat treatment. You can see that the “cheap” AUS-6 with low wear resistance can cut just as long as the high wear resistance S110V. That is if the AUS-6 is at 12.5 dps (25 total degrees) and the S110V is over 20 dps.

So this is another case where knife buyers may be confused about what the real effect of steel is. They might have one knife in a “super” steel that doesn’t cut very well and doesn’t cut very long all because the knife has a thick edge. Then another knife in a common steel that cuts great and keeps cutting. They conclude that the steel type must be nothing but hype.

Toughness

Big chopping knives and axes generally require thicker, more obtuse edges to handle abuse. Below I have images of AEB-L knives that I tested with controlled impacts at 15 dps vs 25 dps. With the 15 dps edge it only took 0.31 ft-lbs to generate a good size chip, and 1.36 ft-lbs to completely blow out the edge. With 25 dps with the same 1.36 ft-lbs there was just a minor ripple.

So just like with edge retention, the edge geometry is going to be most important, before steel type or heat treatment. However, there are real differences in toughness between different steels. Some are more prone to chipping and breaking than others:

I have definitely seen more broken Spyderco knives in high hardness Maxamet and Rex 121 than I have in higher toughness steels. That is the tradeoff. Engineering is all about tradeoffs. If you want the ultimate in wear resistance you will no longer have the ultimate in toughness. Some steels will have a higher wear resistance for a given level of toughness, but there will never be a magic steel that is perfect in every category. This is another of the many reasons why you can’t just say that there is no difference between steels. The right steel should be chosen for the right knife and the right buyer/user.

Toughness is one of those properties where you have enough of it until you didn’t. Either the toughness was sufficient for the task and there was no chipping or breaking, or the knife failed. So there can always be a debate as to whether how much toughness is enough. Because that will change based on the edge geometry and how the knife is being used.

Hardness

Hardness is less a reflection of steel type than it is of heat treatment, but there are still ranges. Some steels can’t go any higher than 60 Rc or even lower. Some steels like the “super” high speed steels can go all the way up to 70 Rc. Hardness is another of the places where I see people misinterpret steel properties, especially when it comes to relatively soft steel. Knives with soft steel will almost always deform rather than chip. This is sometimes misinterpreted as the steel having high “toughness.” If a knife edge deformed it failed due to insufficient strength, not because it was high in toughness. For example, knifemaker Shawn Houston compared an ESEE in relatively soft 1095 and compared it with a MagnaCut knife with similar edge geometry but higher hardness. In the nail chop test the 1095 failed due to deformation while the MagnaCut did not. This was due to hardness, not toughness.

Corrosion Resistance

Stain resistance is one of the more obvious categories, I think, and is less debated. Stainless steels rust less than non-stainless steels. And there are some stainless steels that are better than others. For some buyers it is acceptable to keep their knives oiled and the environment and use isn’t a problem for corrosion. But in either case I think we can all agree that some steels (when heat treated properly) show better resistance to corrosion.

Sharpening

Another area where people generally tend to notice steel difference is in sharpening. However, even in this case it isn’t as simple as some people perceive. Edge geometry is also important for sharpening. Thin edges require very little material to be removed, so even high wear resistance steels aren’t much more work to sharpen. It also matters what abrasives are being used. I used very hard CBN abrasive in my CATRA knives when resharpening and there wasn’t much difference between 8670 and Rex 121 in terms of how much strokes were required to raise a burr. The mechanical removal of material was more the limiting factor. It also matters to what level of polish you are taking it to. Those CATRA knives were only being sharpened to 400 grit. Polishing to high grit levels, especially with softer abrasives, can take much longer with high wear resistance steels with hard vanadium carbides. Heat treatment is also a factor. I found that deburring and getting a crisp edge was challenging with steels that had high retained austenite. I don’t have the space to write about what retained austenite is here, but you can have high retained austenite in virtually any steel if it is heat treated improperly.

Summary

So there was my little rant about whether steels are all the same and no one can tell the difference. They are different. And even if you didn’t notice that doesn’t mean they weren’t different. There are a lot of factors that can control whether someone notices when one knife is outperforming another, with steel being only one of them. And the bigger factor might just be commenters trying to win points with their spicy opinions about steel choices.

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