Cpm-m4

A

AngryFraggle

Joined
Dec 19, 2010
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19
Thoughts?

Any anecdotal experiences as to how it compares with CPM-D2, S30V, ZDP-189, CTS-XHP or Elmax (since that seems to be the hot steel of late)?

Any real-world observations would be most welcome.

Thanks!:thumbup:
 
I am not sure if that is a "new" steel or not. But I would really like to know what Elmax is. So I am looking forward to seeing all the info I can pick up on this thread.

Daniel
 
AngryFraggle said:
Thoughts?

Any anecdotal experiences as to how it compares with CPM-D2, S30V, ZDP-189, CTS-XHP or Elmax (since that seems to be the hot steel of late)?

Any real-world observations would be most welcome.

Thanks!:thumbup:
Click to expand...

http://www.bladeforums.com/forums/showthread.php?t=792540

bladesteel50Kview-1.jpg
 
Great post, knarfeng! But it was my understanding that ZDP-189 should hold an edge better than CPM-M4, since it's harder. CPM-M4 is tougher, though. Do you think your results may have been an abberation, or did it turn out as expected? Because I've been eyeing the Spyderco Gayle Bradley and Stretch 2 for a while now, and if that graph is accurate, I know for sure which one I'm getting.
 
Any thoughts?

Yes

Knife companies don't nearly use enough of this steel!

Tsuigiri, ZDP might have better edge retention at Rc 67 but your not typically going to find that on a production knife. Overall though, CPM-M4 is the better steel IMO.
 
knifenut1013 said:
Tsuigiri, ZDP might have better edge retention at Rc 67 but your not typically going to find that on a production knife. Overall though, CPM-M4 is the better steel IMO.
Click to expand...

Although it looks like he tested those two exact knives, so I'm surprised that the ZDP lost so badly to M4. Since CPM-M4 is tougher and doesn't have chipping issues, it's starting to look like it's better than ZDP-189 in every way except rust resistance.
 
He did but note the 62Rc of each, that will effect the performance of both steels.
 
I believe M4 should have better edge retention than M390 because of the combination of higher hardness and high carbide volume, though I guess that depends on the volume of chromium carbides in M390 given that it has more carbon.
 
On the job as a woodworker, CPM M4 (at least with a high hollow grind - Spydie GB) outperformed all of my other steels. Haven't tried CPM D2.
It's weird how good it is.
I drool at the thought of having CPM M4 chisels. A company or two are making 'em, but I can't justify the purchase since I have 40 billion chisels already.
It most definitely will rust. A small amount of love is required to keep it spiffy looking.
Great steel... sets a very high standard, IMHO.
It did slightly better than M390 on the job for me.
Straight cuts? Almost equal.
Weird, winding, laterally stressing cuts? CPM M4 required less touch up at the end of the day (lotta days testing the steels - CPM M4 did better every day for me).
Disclaimer - There was nothing scientific about my tests, just many hours on the job using many different steels doing the very same thing.

I talked to Mr. Gayle Bradley on the phone a while back. Don't quote me, and I don't want to speak for him, but he was saying something about how his
Spydie collab setup was almost a prybar (NO, please DON'T pry with your knife).
Wonder if the prybar statement could be made about M390...
 
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ankersons sisal tests put m4 between m390 & zdp. but both knarfeng & ankerson cutting 3/8s & 5/8s sisal gave the edge to m4. as knifenut 1013 mentioned the rockwell on zdp was'nt as high as it could go but knives with zdp in 67r.r. are rare. anyway i'll take the super charpy index advantage of m4 over zdp anytime. i do'nt think any cutting contests were done with zdp but m4 certainly is a favorite.
dennis
 
DennisStrickland said:
ankersons sisal tests put m4 between m390 & zdp. but both knarfeng & ankerson cutting 3/8s & 5/8s sisal gave the edge to m4. as knifenut 1013 mentioned the rockwell on zdp was'nt as high as it could go but knives with zdp in 67r.r. are rare. anyway i'll take the super charpy index advantage of m4 over zdp anytime. i do'nt think any cutting contests were done with zdp but m4 certainly is a favorite.
dennis
Click to expand...

Yeah, I don't think I would want ZDP in a chopper either. Hard contact can make bad things happen :eek:

Picture1680.jpg
 
Tsujigiri said:
Great post, knarfeng! But it was my understanding that ZDP-189 should hold an edge better than CPM-M4, since it's harder. CPM-M4 is tougher, though. Do you think your results may have been an abberation, or did it turn out as expected? Because I've been eyeing the Spyderco Gayle Bradley and Stretch 2 for a while now, and if that graph is accurate, I know for sure which one I'm getting.
Click to expand...

All I can say from my own experience is that with the Spyderco knives I tested, the CPM M4 held an edge far longer. However, I know that Ankerson also tested both alloys. His edge retention results were similar to mine. The CPM M4 held an edge significantly longer.


Noctis3880 said:
I believe M4 should have better edge retention than M390 because of the combination of higher hardness and high carbide volume, though I guess that depends on the volume of chromium carbides in M390 given that it has more carbon.
Click to expand...

Ankerson and I both tested those two alloys. We got the same result. Neither of us could tell the difference between them when it came to edge retention.

PM alloys are so much more complex than melt alloys that I would hesitate to predict performance based on composition alone. Aside from hardness and composition, there are also differences possible from the complex PM process itself. One of those is the size of the powder particles.
 
knarfeng said:
Ankerson and I both tested those two alloys. We got the same result. Neither of us could tell the difference between them when it came to edge retention.

PM alloys are so much more complex than melt alloys that I would hesitate to predict performance based on composition alone. Aside from hardness and composition, there are also differences possible from the complex PM process itself. One of those is the size of the powder particles.
Click to expand...
That does sound promising indeed, though I wonder where 20CV falls in that scale. I did say before that a stainless version of CPM-M4 would be the perfect EDC steel. Probably not great for chopping or prying, but I believe those tasks require other tools than knives.
 
AngryFraggle said:
Thoughts?

Any anecdotal experiences as to how it compares with CPM-D2, S30V, ZDP-189, CTS-XHP or Elmax (since that seems to be the hot steel of late)?

Any real-world observations would be most welcome.

Thanks!:thumbup:
Click to expand...

Have you asked any Doozers for help? They should be reasonably knowledgeable given their focus on engineering and food processing.
 
Tsujigiri said:
Great post, knarfeng! But it was my understanding that ZDP-189 should hold an edge better than CPM-M4, since it's harder. CPM-M4 is tougher, though. Do you think your results may have been an abberation, or did it turn out as expected? Because I've been eyeing the Spyderco Gayle Bradley and Stretch 2 for a while now, and if that graph is accurate, I know for sure which one I'm getting.
Click to expand...

ive got both, get the gayle bradly. :thumbup:
 
knarfeng said:
All I can say from my own experience is that with the Spyderco knives I tested, the CPM M4 held an edge far longer.

However, I know that Ankerson also tested both alloys.

His edge retention results were similar to mine. The CPM M4 held an edge significantly longer.
Click to expand...



After testing two CPM M4 blades (a Spyderco Mule and a Custom),

...I too was excited about the edge retention of CPM M4. :thumbup: :cool: :thumbup:





Big Mike
 
Noctis3880 said:
That does sound promising indeed, though I wonder where 20CV falls in that scale. I did say before that a stainless version of CPM-M4 would be the perfect EDC steel. Probably not great for chopping or prying, but I believe those tasks require other tools than knives.
Click to expand...

I have heard that Latrobe buys Bohler M390 and calls it Duratech 20CV. At least they have identical compositions, except for silicon.

http://www.latrobesteel.com/assets/documents/datasheets/DuraTech_20CV.pdf

http://web.boehler.kunden.cmszwo.de/Info/M-Staehle/M390de.pdf


.
 
knarfeng said:
I have heard that Latrobe buys Bohler M390 and calls it Duratech 20CV. At least they have identical compositions, except for silicon.

http://www.latrobesteel.com/assets/documents/datasheets/DuraTech_20CV.pdf

http://web.boehler.kunden.cmszwo.de/Info/M-Staehle/M390de.pdf


.
Click to expand...
I sincerely doubt that Latrobe would do that and that Bohler would supply them with the steel if they knew it was used for that purpose. In any case, I cannot for the life of me figure out how Latrobe would remove 0.4% of the silicon content from the steel after it's already been melted.

Still, I feel the would be fairly different in terms of performance, again because IIRC only Bohler uses third generation powder metallurgy process as of yet.
 
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