Cpm m4 vs cpm 4v for a hunter

rodriguez7

rodriguez7

Gila wilderness knife works
Joined
Feb 1, 2009
Messages
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what are everyone’s thoughts on these steels? Uses could range from a 6 inch blade knife, used for camp, batonning, chopping and skinning, down to a 2 inch caping knife, run hard. The only downfalls I see to m4 is a higher austenizing temp. But overall it’s cheaper per bar of steel, and I’m guessing edge retention will be just a little better. From what I’m getting with blade sports, is 4v is a little tougher with better edge stability.
 
If memory serves, M4 responds well to powder metallurgy so the CPM version stays together (toughness) pretty decent, in real world scenarios. I don't remember the hardness of the data sheets I was looking at when spec'ing a 5" camp knife working with a forum knife maker who did his own heat treats. I know D2 is supposed to be weak, lack toughness, but I've batoned that without issue on several knives. I don't baton with a baseball bat though. I leave the "playful" batoning to the simpler carbon steels that are cheaper and tougher (5160 and 52100 being my favorites).

That said, I don't think I would choose CPM M4 as a long-term big chopper but some batoning shouldn't kill it and I really like in the 5 and under fixed blades. I wish more fixed blades came in CPM M4. I think an M4 puukko or similar sized fixed blade would be a sweet knife.
 
I’m leaning towards 4v. I’ve made one m4 blade, and a few in 4v. Trying to dial in the heat treat a little more. I’m thinking 4v! But I’m wondering what makes 4v tougher than m4? Is it the lack of tungsten? They’re pretty dam close in composition! A dash less vanadium, .20 less if even.
I know m4 at 64 rc cuts pretty dam good. But I’ve been running 4v 61-62 rc and I’m really impressed by it too.
 
Willie71 said:
Ive got some v4e here to heat treat a few coupons for Larrin. I seem to remember someone else offered to heat treat some M4 so we should see if there’s much difference.
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I’m anxiously waiting this too. I recently tested a v4e knife to destruction. It was a higher austenized piece, cryo, low temper. 61-62 rc. It tested very well, chopping antler caused no damage, 18 thousands behind the edge, convexed with a 20 degree micro bevel. Didn’t even chip hammering through concrete, just blunted the edge!!! Surprising. I ended breaking the knife cutting through mild steel with a 1.5 lb sledge hammer. I would place the toughness lower than 3v, but not by much! Maybe 30 percent lower. Guesstimate. It took 29 side impacts with the sledge to break the rest. 3v has taken 50 hits, and still not broken. But the v4e knife was .150 thick! Not an overbuilt knife.
 
kuraki said:
I've made hunters from both. Hell if I can tell the difference between them. They both suck to finish and cut for a long time.
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Totally agreed. They are very close to each other composition wise. I doubt many of us could distinguish the 2. I do believe CPM M4 has a slightly higher overall carbide volume, but not by much, thus making 4v "tougher", in theory.

IIRC, some of the guys in Bladesports who have been using CPM M4 in their competition choppers are leaning towards 4V now.
 
Larrin said:
Can't wait!
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I’ve had almost no shop time this year. I’ve got the next eight days off with only two appointments booked, so I’ll be getting some samples done this week! (Assuming no crisis happen, but this is the slow time of year in my field. People would rather go to the lake, a barbecue, or camping than go to therapy.) And a big W2 bowie!
 
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samuraistuart said:
Totally agreed. They are very close to each other composition wise. I doubt many of us could distinguish the 2. I do believe CPM M4 has a slightly higher overall carbide volume, but not by much, thus making 4v "tougher", in theory.

IIRC, some of the guys in Bladesports who have been using CPM M4 in their competition choppers are leaning towards 4V now.
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Once you get to z-wear/PD-1, 4V, V4E, M4 level of alloying, I think quality of heat treat, and how targeted the heat treat to the application is, plays a bigger roll. This matched with optimized geometry is what will allow one to shine over the others.

My personal z-wear knife needs another sharpening. It won’t shave anymore, and it took a year of daily use to get this dull. I don’t know how much more we need from a knife than that level of performance.
 
Willie71 said:
You have access to some pretty cool steel!
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Thank you!
It helps comissioning Knives from great European makers. My guy Kornalski can get me almost any steel from Bohler and Uddeholm. Achim Wirtz can get me Ultrafort and others (big list).:)
 
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Kevin Cox said:
K890 is a good Steel ,I’ve use it in a chopper before it took a lot of crap before it died. But these days I stick with Z wear.
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How do you compare k890 with Zwear regarding toughness? Edge retention I assume is more or less the same, but I could be wrong.;) I wouldn’t use k890 in a chopper, but I’m glad to know it took some punishment. Out of curiosity, how did that k890 chopper died?
 
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