Let's hear your Thoughts & Experiences on CPM 3V

Daniel Koster

Daniel Koster

www.kosterknives.com
Knifemaker / Craftsman / Service Provider
Joined
Oct 18, 2001
Messages
20,978
Let's have an open discussion on CPM 3V.


All experiences....good or bad.


All I ask is that if you share something that is hearsay...please tell us so. If you can share a first-hand experience...please tell us so as well.


All Comments Welcome!!!







I'll start us off by posting the Data Sheet for CPM 3V



CPM3V-1.gif




CPM3V-2.gif



The important things to note from the above:

Page 1

First things first - note the pictures demonstrating the difference in grain structure with the crucible process vs. standard smelting.


The chart showing 3V relative to other steels in terms of impact strength (toughness) and wear resistance. As you can see, CPM 3V is actually more wear resistant than D2. BUT...it's not as hard to sharpen because it does not have the super-hard large carbides that D2 has.

Only S7 is tougher than 3V...but wear-resistance is practically nill...




Also take note of the composition in the upper right corner. 3V has 0.8% carbon...less than A2 (1%), O1 (1%) and 1095 (.95%)....but more than 5160 (0.60%) - all of which are good tough carbon steels. What this means is that 3V doesn't get as "hard" as those steels (A1, O1, 1095)...but it also means, of course, that it is less brittle. ;)


Look at the chromium content as well (7.5%) and compare to A2 (5.25%), 5160 (0.8%), O1 (0.5%) and 1095 (zero). None of these steels is stainless....but 7.5% is a significant amount of chromium...enough that 3V does not really tarnish...it will rust/pit if left in water, though.


Lastly, look at the vanadium (2.75%) and compare to O1 (0.3%), A2 (0.25%) and 1095/5160 (zero). Also compare to S30V (4.0%). Which means that wear-resistance/edge-holding is going to be much higher than the other carbon steels, but nowhere near as hard to sharpen as S30V.



Page 2


Look at the temper information....tempers at 1000F. Which means this steel can take quite a bit of heat before its temper is affected.

:thumbup:







So, now that we've got the dry, raw data out of the way....let's hear you guys' experiences with the stuff.


Thanks!

:thumbup:



Dan
 
It's my one of my favourite steels for a do-it-all-knife (bushcraft-utility-survival). Why? Because it can handle huge impacts on the edge without chipping or deforming too much (relative!), and still keep a keen edge. Besides that, it's easy too sharpen, takes and keeps a great edge, and is very rustproof for a carbon steel. If you choose carbon, CPM 3V is in my experience on par with steels like Swamprats SR-101 and it sits secure in the top league of carbon knife steels.
I can only compare to A2, D2, 01, SR-101, SK-5, Carbon V and I have no experience with INFI :o. I have 2 blades in CPM 3V, the Bushcraft by Dan and the Shadow Scout by Fehrman.

This is not scientific off course. The edges I used had different geometries, and different materials to cut using different techniques etc..

The fact that Koster does CPM 3V alone (and Paul Bos the treat) made me want to buy A knife from him.. That said.. I wonder who does the treating on the Fehrmans, cause that one is the best edgeholder I ever experienced.


my 2 eurocts..
Have a Nice Day!
martin
 
Dan,
I got one of the first run K-9 Dingos, and it is the first knife in my collection made with CPM 3V. All I can say is that after several good chopping sessions, I can readily agree with Martin. I was amazed to find the edge in what I would call perfect condition after chopping on some green limbs, aged oak firewood, redwood fence boards, etc. I tried to not go easy on it, and it stood up to the test brilliantly:thumbup: I was impressed.

I haven't had my Dingo long enough to comment on corrosion resistance, but I keep a decent layer of Tuf Glide on all of my knives and give them regular maintainance, so I'm not too concerned about that.

I would definitely buy another knife made with this steel based on my experience so far.

Jon
 
Watch out on the Dingo corrosion-wise. I carried mine for the first time the other day, and while it is indeed humid as hell around here I was very surprised to see a reddish-brown powder coat all over the blade when I pulled it out of its sheath---I'd only been walking around about three hours. Bead blast seems to behave exactly like I'd expect it to---creates lots of little pockets where moisture can accumulate.

However, the good news is that the bead blast also creates a surface that rust preventatives will cling to better than they would on a high polish. I always do a coat of clear polyurethane on non-stainless exposed tangs and it works nicely keeping my hands from the steel. It'll wear off eventually, especially if you're wearing gloves, but it's easy to reapply when you get back home. Renwax holds onto bead blasted finishes very well, and I've put knives with that finish into tight, molded sheaths without wiping it off.

Okay, digression aside, 3V is an excellent overall steel in my experience as well. I have to say, though, and I know many disagree, at similar geometry I find it almost EXACTLY like L6 in terms of edge stability and retention in most types of cutting. Now, L6 is certainly the more aggressive ruster of the two, which would make it lag behind in edge retention in a marine or other highly corrosive environment, but beyond that I find their performance too close to call. Well done 5160 nips at their heels in the toughness department, although it lags a little farther behind in abrasive cutting/skinning.

And yes, I'll say it---INFI is tougher. ;) Mind you, this is kind of like saying that Ali is tougher than Foreman---may be true, but either one is/was more than a match for most of the rest of us mere mortals. As to edge retention in abrasive cutting, I don't know. I only have a couple Busses small enough to skin with, and have only used one for that purpose once, and on a very small little deer at that. Would be fun to do an INFI vs. 3V skinning challenge on a hog hunt... :)

I'll share one more anecdote since I've blathered on this long. I have a camp knife in 3V that Bill Siegle made me years ago, and once when I was using it on a ladder to clear away some branches from a bradford pear tree that were growing into the side of my house, I lost my balance, and had the choice of either riding the ladder down or jumping clear. I actually chose a third option by Murphy's Law, trying to jump clear but hooking the ladder with my left foot and pulling it after me in the direction I jumped. My surprise at this was kicked into second place in my train of thoughts, as the first place was occupied by the realization that the lanyard wrapped tight around my wrist wouldn't allow me to toss the knife aside. So before I hit, I stuck my hand way out and landed hard in my yard, slamming the edge down on the driveway beside me. Yes, when I mess up, I mess up big. Yes the edge had a bit of a serrated look where it hit along about 3/4" in the belly, but none of the chips were deeper than about 1/32", and have since all sharpened out with normal use. Took a nice deep bite into the concrete, about 3/16" deep in the center of the arc. Given the force of impact, the lack of damage is really quite impressive as the edge was between 25-30 degrees, included, and had hit a bit sideways.

So, the moral is, yes 3V is a great steel---and don't tie your knife to your wrist when the stability of your footing is questionable. :D
 
Dan - I had a Fehrman First Strike, and now I just got one of your Nessmuk's from the forums here in 3V. The First strike was a great knife, and it performed very well. Never had a problem in any way. I traded it for one of your Monster Nessie's in 5160. Your MN is a much better chopper. I haven't given your regular nessmuk in 3v a workout yet, but I will next week, and report back. I expect, based on the use I gave your Monster Nessie, that I will be all smiles. I will be putting a report on the Knife Review and testing forum in about 2 weeks, comparing one of your Monster Nessies in 5160, against a BRKT Golok, A Busse FBMLE, a Kanetsune Seki KB-117 Kiwami, and a BRKT Bay De Noc, trimming the jungle around my house. I would have it on already, but the pics I took are with my Eagle Scout son, who has the camera, and is with about 1000 other scouts in Bridger Teton national park, doing a service project for Arrow Corp 5. I hope he doesn't delete those pictures. You will be pleased with the results, but I do not want to give anything away here.
Martin - I have heard on the forums, that Fehrman does their own heat treat.
 
I think it is nearly an ideal steel for a scandi grind blade. On almost all scandi grinds you get some chipping if your edge is fine enough. Not so on the 3v.

Now the downside is how slow it is to sharpen, although the diamond plates and stones etc sort of minimize that aspect.

But anyway, yeah 3v is really great:thumbup:
 
Daniel Koster said:
Interesting idea....


Anybody game?



Dan
Click to expand...

Well if you provide the knife :D:foot:

Seriously, I think it could work, but I'm not familiar with surface treatment for power steels.

And on the other hand, I don't know about passivating only a blade. I would probably be better if you treat the whole surface, wich is hard with glued handles. Maybe it should be tried on a pocket lightsaber first.
 
I'll provide the knife...if you'll provide the $$$. :D :p


Yes, I agree it would be better on a full-flat ground knife like the Pocket Light Sabers.
 
As to inducing patina or blueing - I've tried a number of ways to expedite an even patina on 3V. If the steel is sand blasted or blasted with glass beads and completely free of any oils or contaminates you can have pretty good sucess. We haven't blued any but have chemically blackened 3V.

Jay Fehrman
Jn 14:6
 
I would like to see a comparison with rusting after bluing and browning. I have a gut feeling that browning may be a better choice, By the by, you don't need a whole knife blade to do this with, a 1" X 1" flat would be good. Also, since this is a powder steel, you might get better protection from a teflon/polymer grease that with oil or wax. Personally, if I were going to carry a knife with a blade of CPM 3V in Georgia, I would seriously consider treating the steel surface with Brownell's Teflon/Moly Oven Cure Gun Finish and then coating with a teflon grease (allow to sit with grease for 1/2 hour before wiping off) to protect the sharpened edge. I have built a Mauser "truck gun" with this treatment, no rust or corrosion in 3 years of hunting; but, that's with different steel involved. Note: The baked on finish will chip if you don't do good prep work.

When I use a knife in the field I coat the inside of the leather sheath with grease, teflon or military spec. That way it gets extra protection in the sheath. I learned this when I was trying to profect my fast draw, dry leather can sometimes "grab" steel. My gun oxidized on only the part outside the holster. Another aspect is that if the outside of the shealth gets wet, the water wicks out of the uncoated side, not the side next to the blade.

Just MHO.

Jim
 
very interesting...

Jim - if I send you a blade blank - will you give it your "treatment" - and we can do some testing on it?

Would you prefer it glued-up and finished instead?


Dan
 
The only 3V stuff I have is from Fehrman. Using it mildy around the house and yard caused one of the 3 I have to patina a little. Not a good looking patina either.

Aside from that though, tough and good edge retention.
 
I'd rather just have the finished blade or a similar heat treated steel flat (1" X 1"); but, let me check when I get home to make sure I have some Teflon finish on hand (I should). It's harder to get good lines on a blade once its got a handle on it; but, it can be done as long as the grips don't warp. Also, the finish has to cure at an elevated temp. I usually use 120 F - 150 F for 24 to 36 hours, or shorter time at higher temp (better). I'm not sure what temperatures may affect the hardening/annealing process on this metal. I'll send you an email when I see how I'm doing on supplies.

jim
 
I don't think anything shy of 350F will affect the temper. It'll definitely be interesting to see how well this does.
 
just look at the pages Dan posted, six hours at a thousand degrees for the tempering process.
 
Yes - it won't affect the steel at all...

And actually, at that temperature, it won't affect micarta either.

:thumbup:

Dan
 
Good, the hotter I can keep the bake (within reason) the better. Also, I'd like to get metal with a holed drilled, or drill a hole to hang the piece from, if possible. I'll probably clean it in three stages, with alcohol, acetone and petroleum ether before spraying if it doesnt have polymers associated with it, Ethyl Alcohol, if it does.
 
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