CPM M4 for a kitchen knife

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Barmoley

Barmoley

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I know steel is just one of many parts of a good kitchen knife, but what does the collective think of CPM M4. It seems to do really well in all sorts of cutting competitions. It is pretty tough even at high hardness levels, has relatively small grain size for an alloyed tool steel, and should be able to support thin edges. It is wear resistant and can be used at 64 HRC without being brittle. It is not stainless, but more so than 52100 and other usual carbons. Anyway, sounds like it should work....
 
I think that it will be tough to sharpen, otherwise I see no reason why it should not perform well.
 
Could be. But if the edge is held very thin, if the steel can support it, then it shouldn't be that bad. Especially using diamonds....
 
Barmoley said:
Could be. But if the edge is held very thin, if the steel can support it, then it shouldn't be that bad. Especially using diamonds....
Click to expand...

Yes, and that (the diamonds) is the reason why this steels are often used on pocket and outdoor knives - most users of which use some kind of sharpening device that gives them sharp edges in no time (I have one too - forgot the name). Those users do not need to thin their knives (mostly because they use them rather little) all that often (read - not at all).

Still - I am not saying that CPM M4 would be too tough to sharpen - one of the reasons we do not see it much around here is lack of the suitable stock material + price. I was actually looking for CPM D2 and failed to find some.
 
I agree with Matus, but only as a matter of looking at the composition versus actual personal experience using the steel. One of the great things about relatively simple carbon steel is how sharp it gets and how easily that super sharp edge is maintained. I'm guessing the higher alloying in M4 gives better wear resistance due to the carbides formed, especially the tough tungsten and vanadium carbides. But then you probably give up some of the easy sharpening you'd have in a low alloy simpler carbon steel.

Is there somebody out there making kitchen knives regularly from CPM M4? Or are you deciding on a custom?
 
I don't know if anyone is making CPM-M4 steel kitchen knives regularly. My question is academic, I just noticed that it is used a lot for many years now for cutting competitions. Lately, like Matus said it's been used a lot in pocket knives by Spyderco and Benchmade as well as some others. CPM process supposedly allows carbides to be smaller and well distributed, so this might help some in sharpening department.
 
I think Matus is right. The problem is thinning , sharpening would be ok but once you had to thin......

It would probably work well as core steel or for petties, sujis, etc, not so much for gyutos.
 
I think the guy from Houston Edge Works, or whatever its name, is uses it. I also think butch harner may have experience with it if my memory about steel discussions is correct
 
It should be a decent steel for KF, but it's a tough steel, kinda of an overkill for this purpose. But I would consider getting one from a good maker (read HT).
 
These actually look pretty good from the pictures. Has anyone ever used any of them? How are the grinds? I still think that it would be too difficult to deal with when thinning, but a petty or smaller utility knife could maybe work well.
 
Personally I think ZDP-189 steel is pretty close to M4 steel. You may get lots of choice from the former material.
 
Yeah, Hap40 is the closest of the "usual" suspects, even though it is still pretty different, but should act in similar matter given optimal heat treat for each.
 
Does anyone know of any EU makers selling knives in this stuff as of the moment? Or yanks that will ship to the UK?
 
One thing needs to be said - it would appear that CMP/PM steels are easier to grind than non-CPM steels. I have made a little knife from Damasteel (mix of two PM steels) and it was sooo easy to grind and to sand - bordering enjoyable ;) So the CPM M4 does not have to be so bad to sharpen after all. I would say this needs to be tested :)
 
I can get M4 readily available in many sizes. Send me a message on IG Matus if you want me to get ya some.
 
Well, it may take a while, but why not? Steel has already been located thanks to comet_sharp, but I expect it to reach me only in a few weeks and the I will work on the knife next to other projects.

Realistic start of the passaround would be end of the year. No need to sign up for it yet ;)
 
Natto, I will discuss the HT with Jürgen Schanz as he does all stainless and semi stainless HT for me.
Edit: thanks for the data. This steel is not going to be easy to HT I guesd
 
It would be great if you could put some light on this high alloyed pm steels, pros and cons and how to heat treat. In my head this is in a pretty dark corner. Thank you.
 
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