Knife Steel

Forget about the search for the "best" knife steel. It isn't about the best steel, but about understanding the strengths and weaknesses (pros and cons) of different steels. Every year there are several new "super steels" and there is no denying that it is interesting learning about them.

Also forget about finding the final answer here. This page is being constantly revised as I learn more about knife steels.

I am not a knife maker or a metallurgist. This is my own summary of what I have learned about knife steels. You can read about this topic at great length. Lots of people who don't know tell you what they have heard from other people who don't know.

At this point, I have two favorite steels. M4 is one, and M390 (aka CPM-20CV aka CTS-204P) is the other. This is continually changing as my tastes mature and as I gain more experience.

One thing is certain. Proper heat treating is as important as the steel itself. All that most folks can do is to select a manufacturer with a good reputation and trust that they have people who know how to get this done right. The design and manufacture of the knife is almost certainly more important than what steel the blade is made from.

The spyderco "edge steel" thread is worth reading. It names K390, Cruwear, and Maxamet as the writers favorite steels. A lot of excellent discussion follows.

What is the best knife steel? Why, S30V of course. I say this somewhat tongue in cheek, the real answer of course depends. S30V offers an excellent balance of toughness and edge holding hardness. it has also been around a long time, people know how to work with it and get the best out of it. It is well proven. But these days, I tend to view it as a somewhat lackluster knife steel.

This is not to say that S30V is bad in any way. S30V is so well known, that it is the steel to reference all others to. But there are other super steels that offer more, with various trade-offs For a folding knife, S30V is ideal, other steels are good and there are plenty of new steels that are better in one way or the other. I consider S30V as the first of the "super steels".

Note that the "super steels" with high vanadium content hold their edge very well, but are correspondingly a real task to sharpen. It is best with them (and with any knife) to keep them sharp rather than let them get dull and then try to get them sharp again. It has been said that S90V and S110V are almost impossible to sharpen.

I classify steels into the following categories.

Crappy steels

If you are spending decent money for a knife you won't see much in this category. 440 steel that is not explicitly labelled 440C could be considered in this realm. Any knife that doesn't designate the steel it is made of is almost certainly in this class.

Carbon steels

Steels like 1095 are non-stainless, but extremely tough and are ideal for chopping tools, machetes, tomahawks, and the like. If they are not used in a big chopping tool, you are probably looking at a cheap knife that will be easy to sharpen, but will rust and get dull quickly. I have two fixed blade knives with carbon steel. One is an Ontario Knife RD-6 "Bush" in 5160 steel. The other is an ESEE Izula-II in 1095 steel. These will rust, but are very tough. All part of the tradeoff game in steels. 5160 is used for vehicle leaf springs and is perhaps tougher and more rust resistant. But the differences are minor and qualities of 1095 depend greatly on the heat treatment.

OK steels

Here we have AUS-8, 440C, 8Cr13MoV, CTS BD1 and others. All good stainless steels. In general easy to sharpen and affordable. People say that AUS-8 and CTS BD1 and 8Cr13MoV are effectively the same steel. The claim is sometimes made that 8Cr13MoV is an "upgrade" to AUS-8. This is probably true and may have been a selling point when AUS-8 was in common use. These days, with steels like 154CM and S30V available, there is little excuse for using one of these steels unless the knife is offered at a low price. Steels in this class should be easy to sharpen and take a good edge. However they won't hold that edge as long as one of the super steels.

So you face a conundrum. Do you want an affordable steel that you can sharpen well (but need to sharpen more often). Or do you want a hard to sharpen steel that because you are unable to sharpen it, actually gives you a poorer but long lasting edge? The truth is that many people without advanced sharpening skills may actually be better served by a steel in this class than one of the super steels.

CTS-BD1 was made by Carpenter for Spyderco. Here is What Sal Glesser said about it:

Carpenter Steel created CTS-BD1 at Spyderco's request. We wanted an ingot steel that had good performance in edge retention, toughness and corrosion resistance, but was less to purchase and process than the powdered steels we've been using. Something we would use in our "basic" models to lower mfg cost (and retail price) and use in our kitchen knives. The closest chemistry to what we wanted was a steel produced by Hitachi called Gingami 1 (GIN-1, G2). We had much experience with the steel and have been importing it from Japan. I asked for something equivalent or better. They tweaked the forumla and game up with BD1, which was an even better performer than Gingami and was USA made. Carpenters metallurgists are first rate. BD1 has hi-powered trace elements in the formula ...

Great steels

Here we have S30V and 154CM. Both are wonderful steels. 154CM is essentially the same as ATS-34. ATS-34 is made in Japan (by Hitachi) and no longer exported out of the country. 154CM is used for some big blades where S30V is perhaps too brittle. Spyderco has offered a mule in RWL34, which is essentially a version of CPM 154 made by the Swedish firm "Damasteel"

VG10 is a japanese steel that is very similar to 154CM. You hear again and again how VG10 is easy to sharpen to a fine edge. You don't see VG10 as much as you used to though.

S35VN is S30V with some niobium added. This makes it easier to machine, but is not especially better than S30V for the end user.

The thing about S30V is that it has been around a long time, is well understood so you can feel confident that people know how to properly heat treat it. S30V seems to loose a fine edge quickly, then keep an excellent working edge forever.

Super Steels

Here we have S110V, S90V, M390, M4, CTS204P and others. Be the first on your block to collect them all!

Note that the numbers in the S-series indicate the percentage of vanadium. S30V has 3 percent. S90V has 9 percent. S110V has only 9 percent though.

Also note that S30V is tougher and easier to sharpen (but not easy) than S90V or S110V. What you get with S110V is superior edge holding. The concensus seems to be that S110V is a tiny bit better than S90V.


I have some kitchen knives by Wusthof and am told that they use X50CrMo14 at 56 HRC. X50CrMo14 is very similar to 425M. Note tha 425M is similar to 440A and in the above list would barely make it to the "OK steel" category. So this is an easy to sharpen stainless steel that will need frequent sharpening, but take a good edge. It is not in the same class as the pocket knife steels being discussed above. Buck used to use 425M in its knives, then moved up to 440C and 440HC.

Note also that many pocket knives get hardened to 60 HRC or so.


Spyderco offered this in one of their mules (now long gone). And 10-5-2017 they announced a PM2 with CF and 52100 as a limited edition. The 52100 steel has a strong following. It only has a few percent chromium, so it will rust, but it seems that all the best steels are non-stainless. 52100 was developed as a ball bearing steel. Compared to "ordinary" tool steels like O1 and such, it is much more consistent and refined. It is easy to sharpen to a superb edge, and though it doesn't get big points for edge retention, it is easy enough to sharpen that it just doesn't matter. Apparently Spyderco heat treats the 52100 to 62-63, which is much higher than the usual 57-58 used for other carbon steels (like 1095). Prior to Spyderco getting it in sheets and working with it, it was used by a handful of custom knife makers who forged blades from big pieces of it (large bearing balls?).

The 52100 Military was a sprint, the PM2 is/was a distributor exclusive.

Sal Glesser said:

It was a real PITA to find it rolled to the thickness wanted. It's also a bugger to work with in a production environment. Not too many production folders out there in 52100. I can see why.
Someone said:
52100 will start to patina and even form rust spots just from chilling in a pocket for a few hours. The tradeoff to this is excellent wear resistance and sharpenability. I swear you could probably pick up a rock and get it hair whittling sharp with little effort. Then you can beat it on it like you would M4 and it won't care. It doesn't hold a freakishly sharp edge as long as M4 will, but again it's so easy to sharpen up that I feel encouraged to use it more than my M4 knives.

52100 is just a fun steel. It invites you to use it and it pays dividends when you take care of it properly. A lot of popular steels nowadays you can just abuse and throw in a corner. ... a knife guy is missing out if he doesn't give 52100 a go.

People wish that the Nilakka would be made with 52100 instead of S30V. This is a unique folding knive with almost no edge bevel and a very thin blade. It is a folding rendition of a Puukko knife.
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Tom's Knife Info / tom@mmto.org