Which tool steel do you prefer in a folder and why?

Oct 14, 1998
What tool steel would you use in a pocket folder if you could use any steel? Buck has seen the light (at least partially) in their Master Series (if you want stainless steel) but, I am thinking more along the lines of a Benchmade M-2 knife.

I am considering a knife in the 3 to 4 inch range in a clip point, drop point, or similar format that is not overly thin at the tip like the Benchmade AFCK or Leopard.

I am aware of one custom maker who uses 1095. While 1095 can be differentially heat treated, it seems that something like A2 would be a better choice. A2 has good toughness and is a proven steel. M2 was chosen by Benchmade for a reason over the others but, at this point I'm not sure why. Have I just been swayed by A2's performance in fixed blades so, I am now missing the virtues of another good steel. Please share your thoughts!


p.s. If you have custom makers or websites in mind, please post the contact info! Thanks!
BG-42 or 440C are my FAVORITES!!!
Nothing bead blasted unless it is coated with clear-T.
ATS-34/154CM is OK if it is high or satin polished, or coated with clear or black-T.
Good question Sid.
There are lots of good tool steels. My choice for a folder right now, if I had a maker who would use whatever I requested, would be CPM420V, without a doubt. BG-42 would be my second choice, and A-2, or M-2, or O-1 would be good too. It is all good as long as it is heat treated well. The low alloy stuff is a little more work to keep clean.

Well, EDI has a Genesis coming out with A-2 tool steel. It'll be coated with chromium nitride. It's limited to 500 pieces (I think), so get one on order while you can. Howard at The KnifeCenter is taking orders.


Deo Vindice

WHAT? Did I hear you correctly?

I spent some time at the EDI booth at the SHOT SHOW and saw some nice things but, I don't remember an A-2 production folder. Is that a groan I hear from my wallet :)

I like A2, esp when it is clay tempered as per Sean Perkins(high 40's at spine 63-66! at edge). The CPM V series (3V, 10V...) sounds very enticing, but I haven't ever used one.
3V is designed to be very chip resistant, good for a tactical knife and the others have different levels of wear resistance and chip resistance. The one I want to see is CPM Rex 76, it is designed to be used at RC67-69!

Why did you stab that girl?
You won't believe this, but I had too much coffee!
-Edmond by David Mamet
The A-2 Version of the EDI knife will be offered right here at the BladeForums.com store since it is a limited run. We can not however offer the regular line. We will take advance orders on it soon after the store opens. They will be $174.95

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Mike Turber
BladeForums Site Owner and Administrator
Do it! Do it right! Do it right NOW!

Believe it or not in a folder I am sold on Spyderco's ATS-55. Have it in my C16 and without a doubt one of the nicest steels to sharpen and hold an edge. I have had folders in AUS-8(CS), 440C, what they use in buck and camillus folders, ATS-34, and some high carbon in older folders. ATS-55 wins hands down in my opinion. Shows good edge toughness, good flexability on the edge,(brass rod test), sharpens up very easily on my Lansky and holds the edge for a long time, and the edge depending on what you use to sharpen it up with can go to a high polish if you like or an edge with some bite.
Just litely hit the edge with my med. grit diamond when it starts to pop hair. Gives the edge a great bite for stainless. keep'em sharp
D2 is my favortie tool steel by far. Yes you can get a real edge on it and it will hold it.


Tom Carey
Well, this is a good question. Edgeholding, toughness, stainlessness, what do you want? In my folder, edge-holding is probably my top priority, providing I can get *enough* toughness and rust resistance.

420V would seem to provide unparalleled edgeholding with excellent rust resistance, and acceptable toughness. It's a fine choice.

D-2 is another great choice. It'll need a little more maintenance, but is easily tough enough for anything I'll use a folder for, and holds an edge like crazy.

If I'm going to look at steels that rust quickly (and so either need to be coated, or maintained more carefully), the steels named like M-2, A-2, and O-1 would all seem to be fine choices. Even 1095 left hard works. M-2's edgeholding over A-2 and O-1 probably give it the nod for me.

Another great choice would be 52100. Incredible edge holding, tough enough for a folder. Like the ones named above, it would need to be coated or maintained a bit more carefully than D-2 or the stainless steels. Rumor has it 52100 may come -- or already comes -- in a form other than ball bearings.

There are a few limited sources of 52100 in forms other than ball bearings. Sheffield's Knifemakers Supply carries it in bar stock, but the only size they have is 3/4" wide by about 3/32" thick in up to six foot lengths. It was part of a run that was split between them, and I think Steve Schwarzter. I think Wayne Goddard is also taking orders currenty for a batch of 52100, but don't know how long it will take to be produced, or who will get it. I think sheffields said that in order to purchase it in bar form, they had to order several thousand pounds of it, since otherwise the steel mills won't consider an order.

The only drawback I see to it is that it takes a fairly complicated heat treating process to work well, and it takes more care than a tool steel. I don't want to argue semantics, but I don't consider 440C, BG-42, ATS-55, etc. to be tool steels either.

I'm a big fan of D-2, not just in the edge holding and durability in a small, thin blade, but in its ability to stay fairly straight during heat treatment, which is a blessing if you're trying to fit a folder together. You can grind a blade pretty close to finish size, and not have to worry about it warping. Otherwise, its heat treat the blade, surface grind it to assure its flat again, then finish grinding the bevels.
I know one maker using stainless steels that has their folder blades profiled and drilled for the pivot, then heat treated before the final grinding, just to control warpage. Of course then you have to be careful not to heat the blade too much while grinding the bevels and destroy the temper in it.

Like someone else pointed out, the drawback to something like A-2 or M-2 is that you have to either really take care of it, or have the blade coated with something to keep it from rusting. D-2, while it will stain a bit, is about the most rust resistant tool steel out there, and will hold up with minimum maintenance.

madpoet -- I wasn't sticking with tool steels because no one else seemed to be either ...

Okay, so for my personal preferences, I'm seeing some choices emerge. I'd like to see some 420V when edge holding and stainlessness are top priority, and D-2 when edge holding is still a top priority, toughness is more important, and "semi-stainlessness" is good enough.

Here's the hard part -- what if we don't care at all about stainlessness? What's a good choice to balance exceptional edge holding with good (doesn't have to be great; this is a folder) toughness? There are plenty of good choices here, like M-2 or A-2, but from a knifemaker's point of view what would you choose (a steel that's easy to heat treat, etc.) M-2? L-6? Assume we're not going to let you differentially heat treat it.

Heck, lets assume you can differentially heat treat as one option and not in the other. A fair comparison may even be to differentially heat treated a blade of say 1095 and compare it to something along the lines of A-2 or M-2 which isn't.

As mentioned above, an A-2 differentially (clay) heat treated sounds mighty enticing.....hmm

As to the issue of stainless steel, blade maintanence, etc. I have had ATS-34 rust on me so, blade maintanence with a good coating seems to be mandatory, at least for me.

Edge holding and toughness seem to be the key here, to me at least. I have considered the 440v/420v steels but, toughness seems to be an issue when the blade tip gets thin. This is what led me back to the thought of tool steels. A BM AFCK is pretty thin at the tip but, M-2 seems to have answered the question of pure strength there so, this led me to thoughts of 1095 and A-2. It's also nice to be able to touch up the edge easily which seems to be a vote in favor of tool steels in general (and a vote against the 440v/420v sttel).

While I don't stab car hoods with my pocket knives, I have opened a can or two with them. This isn't as severe a use but, one that pocket knives do see in a more normal "uses". How many of us have cut wire and opened wooden crates with what ever we had in our pockets? I would feel better with a tool steel knife then a stainless one (assuming the same blade profiles) any day for uses like this. Now, I'm thinking over the options......

Sid I have. Its one of the reasons that I tend to always want to carry a knife that either has good edge toughness, or I don't really care about mangling the edge as its is so soft its easy to refit.

I would be interested to see which steel O1, D2, M2, 3V, or L6 has the highest impact toughness.

I believe that 3V was designed specifically to enchance resistance to chipping in very strenuous environments.

Why did you stab that girl?
You won't believe this, but I had too much coffee!
-Edmond by David Mamet
I don't think toughness is an issue with CPM420V. As I understand the specs, CPM440V is already tougher than ATS-34, and 420V is significantly tougher than 440V. I have hacked at PVC pipe with my thin-edged Krait without any edge damage. 420V is not all that easy to re-edge if you get it really dull, but touches up as easy as anything else if you are just maintaing the working edge.

I am thinking, since it is a folder, it will be getting slightly less forceful application than a fixed-blade might. For example, most folders aren't super choppers.

I still say they are all good though. M-2, A-2, D-2, CPM420V, differentially tempered O-1, its all choice stuff. Heat treated right, it is going to make a superb blade for cutting. If you want to be able to pound your blade through a bolt head, better find somebody to make you a blade of mildly tempered 1056 and not get it very sharp.

Steve, while I don't cut up bolts I do heavier/tougher work with my folders than hacking at plastic. Not everyone has the same performance requirements. Some people want ultra thin, highly polished, low ground, extreem RC knives (65+ RC). These cut paper, cardboard, whittle wood and do food preperation exceptionally well. Other people like more durable knives as their edges get more of a going over so impact toughness is important and 3V is much better in this respect than 420V. Other people carry both kinds.


[This message has been edited by Cliff Stamp (edited 09 March 1999).]

3V is a specialty steel, for applications where ultimate toughness is desired over edge holding.

Why would a person need ultimate toughness in a folder blade?

The pivot of any conventional folder that I know about, including the Sebenza, is going to be thrashed beyond usefullness by any regular abuse that would even begin to approach the capability of even an A-2 blade.

Same with chopping. It just doesn't make any sense to put 4" axe head in a folder. There is only so much chopping you can do with one.
The best tool steel for a folder is one that is tough enough for the moderate torquing and impact that the handle and pivot can regularly tolerate, and will take and hold an edge like crazy. CPM420V fits that description as well or better than any other steel I know about. If 420V is too abrasion resistant for a person, any one of the standard cutlery tool steels that are a little easier to sharpen will do fine if heat treated properly. 420V is tough. PVC is hard. Ever try to cut it?