Talking Steel: CPM-M4 

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Good information. I am guessing the balance of harder and softer carbides is how the manufacturer controls chipping and breaking. All hard vanadium will yield great edge retention but the trade off is chipping. Some steels are designed for harder use (greater toughness for abuse) and others for long extended periods of use (greater hardness for edge retention). The right steel, geometry, thickness, and heat treat when paired with a good design truly is an engineering masterpiece

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Glad you liked it and are getting into pocket knives! You definitely started with a great one. M4 is a great steel for a blade and honestly absolutely one of my favorites! Keep in mind that the particle metallurgy process is a really big part of what has allowed M4 to stay so relevant. A combination of old and new!

@@EngineersPerspective701 Yep, particle metallurgy has definitely enhanced M4’s performance. Of course, comparable steels use PM technology and techniques as well, to achieve their performance. 😉

Very good note! I had forgotten all about it so I had to look it up again. Love how companies put out crap soft s35vn hiding behind toughness or some other bs. Just makes it clear that they never did the testing to maximize the toughness.

Generally 3V isn’t run hard enough or have enough carbide to make it into my enjoyable steel category although it’s super easy to move on the stones and takes a fine edge. Elmax doesn’t seem like anything special to me. Rather go S45VN or Magancut

@@EngineersPerspective701 - Roger that. I think Spyderco does 3V about as well as anyone has. In the Schemp TUFF, anyway. Mine performs well. And my 9500 series ZT 0561 in Elmax performs very well once I took about 1 mm of burned steel off the edge.

@@EngineersPerspective701 - why not do a video series on the processes of making various steels? CPM, CTS etc etc vs conventional ingot steels. There's much about the powder metal processes I'm still confused about. I'm sure others are as well.

@@holdernewtshesrearin5471 Larrin Thomas has some incredible articles on his Website “Knife Steel Nerds” Here is the magnacut article but there’s definitely one on different steel manufacturing. knifesteelnerds.com/2021/03/25/cpm-magnacut/

@@EngineersPerspective701 - thanks brother.

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Not a collector either! Most of my knives look like hell from use or experimentation of some kind! It may be worth keeping the PM2 just for M4 but I'm sure you can make some money on the one you have while still picking up another M4 blade for less. I really started having the same appreciation for smaller blades once I got into the Para 3s and native 5s. I fully prefer that size and it becomes more apparent as working knives. The precision and ease of use totally trumps the extra blades length most people put as a qualifier for a "work knife". A K390 dragon fly would be absolutely awesome. Probably the most cutting in that size package that has ever been produced by man! It won't feel as stout or refined as the lil' native but it's a sweet little blade.

@@EngineersPerspective701 I assumed I would sell the M4 PM2, but they must be making more of these exclusives, because the Ebay selling prices have been close to what I paid. I still may sell it... I think I'd be happier having my money in a Brouwer (and they're already disappearing). I like the idea of putting a liner-delete copper scale on a Brouwer, without it getting crazy heavy like most copper knives. The Brouwer would probably be an ok recycling knife as well... less length, but pretty thin behind the edge. It's hard to justify keeping the PM2 just so I can cut cardboard slightly faster, lol. It looks like you've got bigger hands, so I can see why you'd prefer the full-sized Native 5. The attraction of the Dragonfly is also that it will basically disappear in the bottom of the pocket (just like my Victorinox Compact, which I mostly just carry for scissors), so I can always carry it as a secondary.

Thanks man! Accidentally let it go live 😂Rerelease on Fri

Email is now sent, @@EngineersPerspective701.

@@SteveKluver appreciate it, I’ll take a look!

I just turned it into a Google Doc, and sent you a link, @@EngineersPerspective701. So the formatting on your device, will be less of an issue : - )

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You’re welcome!

The Ritter Hogues are extremely special knives. I currently own 4 and just ordered a jade automatic Ritter Hogue. By far my favorite knives in my massive collection.

Emailed you back, thank you!

I put these pages together. I can't speak for collectors but really it's a good steel for anyone who isn't concerned about corrosion. Can take relatively low angles, holds front end sharpness and has enough carbides volume to break down into a very solid working edge. All good stuff

How can you not go on a K390 kick? It's freakin awesome! I've been using Maxamet and 4V mostly right now but K390 is soo good.

@@EngineersPerspective701 Yeah bro ! I hear that with Maxamet! I've only tried 3V so far. No 4V for me. How do you like 4V ?

@@doejon9424 definitely still forming my thoughts on 4V still but it’s a lot like a M4 honestly. Probably will have more edge stability but I haven’t pushed it too hard yet other than hitting a staple when cutting out our old carpet. No damage but blunted.

@@EngineersPerspective701 I've experienced micro chipping with 3V before. Not so much on M4. I still remember my first experience with M4 on a Spyderco "Air" and it was excellent. I immediately wanted the steel in a bigger knife. M4 used to pretty rare on folders

My first M4 was the PM2 and it was a next level of performance. Great up front sharpness like I'd never experienced at that time and solid working edge that cut forever. Sharpened better than most of the steels I had too! We definitely live in an age of luxury where M4 is readily available along with K390 and Maxamet.

Pretty low, in the realm of Cruwear or Hap40. Possibly slightly worse but it depends on the heat treatments. Notably better than a 1095, 52100 type of basic carbon steel

Substantial differences. Two cases to look at because I also have 10V that is a lower hardness than the K390 I have and they perform extremely similar. Note that I do really like M4 and find it to be a steel that I can comfortably use without feeling like I'm giving up anything. If I had to grade their performance it would go like this. M4 (62-64HRc) = B 10V (63-64HRc) = B+ K390 (>65HRc) = A+ 1) 10V at same hardness as M4 (63-64HRc): In short, 10V/K390 at the same hardness feels exactly like M4 but on steroids and takes longer to apex with the same abrasive. Every property is either equal or better essentially. They both hold the same up front sharpness but 10V comes up WAY stickier in sharpening. Even if over polished it quickly develops into a sticky edge after a bit of use as those VCs are exposed. M4 holds onto whatever the original edge you put onto it until it dulls enough to form a working edge. The quality of the 10V working edge is superior and is able to cut things that M4 will struggle with for longer. 2) K390 as higher hardness (>=65HRc): Not even a close comparison. It's a totally different class of performance. Much higher edge stability. Longer up front sharpness, same working edge as 10V.

@@EngineersPerspective701 No wonder they put in the production model for the Seki model line-up. I wonder why more manufacturers haven’t picked it up versus M4.

@@nandayane the seki K390 is amazing! And they’re geometry tends to be better than 80-90% of what’s out there too, delica came at 0.015” BTE at 17dps plus the super thin spine and distal taper

@@nandayane my guess is M4 is more known and easier to machine

@@EngineersPerspective701 Gotta give Sal respect for putting it in the seki line of knives. Spyderco really is run by a steel nerd! I guess that is one way to justify the “spyder tax” put the best steel you can find in your main line-up.

“Mostly and impurity” maybe better said as a functional impurity? It has specific functions in the production process dealing with oxygen I think but it being leftover at the end isn’t necessarily positive I’d say. Possibly helps a little with machinability. Diamonds/cbn definitely make M4 a sweetie. Very good overall steel. Like you though I’ve also “graduated” to a little higher tier of steel for my personal preferences