Heat treat of CPM 3v: Bark River, Fehrman, Koster

G

glubse

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Aug 21, 2011
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First, let me say that I'm not a knifemaker myself, just an interested layman, therefore I'm not familiar with the in depth processes.
My question is this: the heat treat for CPM 3v seems pretty straight forward, at least according to the Crucible data sheet, meaning there isn't much space to experiment (I don't know about the difficulty level of the heat treat with this steel).
However, I read very different feedbacks for the makers specializing in 3v.
For example, I barely hear complaints about Fehrman knives and if there are (for example virtuvice on youtube), they say there's some difficulties to resharpen them.
On Bark River I read good feedbacks as well as bad ones (micro chipping being the problem with the not so good feedbacks). So, I'd like to know: what are your experiences with the 3v of the different makers and which parts in the heat treat do they do differently?

Btw: I don't own a Koster knife (I plan to), I just threw in the name because he does a lot with 3v.
 
I have several Bark Rivers in 3v but I have not experienced any chipping although I have not used them on deer as virtuvoice does
 
I have used two 3V knives, both made by Bark River.

The first is the Lil' C and it came with a very rough edge.
I had to reprofile it on my 1"*30" beltsander.
After this it performs as expected, among the top edgeholders I use.
At HRC 58 it has the maximum focus on toughness and the resistance against abrasion is lower than my harder stainless powdersteel blades in SGPS.

The second is the Liten Bror and it came with a fully usable edge.
I have only needed to hone this edge, no need so far to sharpen the knife.

It's a great steel and I would like to see it in a larger knife around 8" blade at HRC 58.


Regards
Mikael
 
From what I have read on the forums, I am pretty sure that Koster is adamant that 60 is the only hardness that he will use on CPM-3V.
Bark River uses 58-59.
I haven't read about what Fehrman uses.
 
Well I just recently got back from an elk hunt here in new mexico. I got to use my new bark river bravo 1 3v on 1 elk and my fehrman peacemaker on another. Full size bull elk, both. Both blades did wonderfully. I didnt have to sharpen either in the middle of field dressing. Just a strop after was all that was needed. 3V is one of the best steels I have used. I did use some infi on the first bull for a while. But didnt care for the edge it held. I know fehrman runs theirs at around 57-59 rc. But this peacemaker held an awesome edge. These are my go to knives for all my hunts from now on. Hopefully this weekend they will be put to use on our deer hunt. No micro chipping as far as I could tell, and the skin was full of mud from wallowing.
 
There are two separate issues here.

1) Matching the proper hardness to 3V (or any other steel), given the geometry and proposed use of the knife. In the case of 3V, the key characteristics are its extreme toughness within a hardness range that also has excellent wear resistance. But a lot depends on the hardness you select. At 62 HRc, 3V is just a little tougher than M4, but has a lot less wear resistance. At 58 HRc, 3V is much tougher than M4 at HRc 62, but M4 at that hardness has much better wear resistance.

So part of your question is not which maker has the better heat treat, but which heat treat produces the hardness that best fits with your particular knife and what you intend to do with it. In a chopping contest where you are cutting 2X4s in half and slicing and dicing straws, you want a steel that is tough enough to avoid damage while holding a fine edge as long as possible.

2) The art and science of tweaking the heat treat that a the knifesmith brings to his craft. Bob Dozier is known for wringing the best out of D2. Ed Fowler does the same with 52100. I've read where Phil Wilson runs an oven with multiple temperature sensors so that the entire blade gets an even heat treat. Others differentially heat treat the blade, but whether that kind of heat treat is better depends on your knife and what you use it for.
 
Cliff stamp has some great data points on 3v and on how the fehrman knife he tested probably had the edge put on to fast, thus leaving the edge weak, it's was interesting to hear how 3v was not even meant to be used for blades.
 
1) Most steel was not originally designed/intended intended for knife or hand-tool applications.

2) There are contract Heat-treatment organizations which perform the HT on the knives of many producers. AFAIK Bark River does NOT do their own HT. Survive! uses Peter's HT. I don't know about Fehrman or Koster. Phil Wilson does all his own heat-treatments. For those who outsource the HT, they just decide upon a final hardness and leave the rest to the HT-folks. A few points of hardness can affect performance in a variety of ways. HOWEVER, there is speculation that final GRINDING can also affect the steel matrix along the very thin edge of a knife. Over-heating an edge can temper it too soft such that it rolls and deforms easily, and over-heating followed by fast quench can make an edge brittle, more susceptible to chipping that would normally be the case. Both of these issues are referred to as "burnt edge". There is also the matter of manufacturers leaving a micro-burr along the edge which can tear-out or fold-over and dull an edge that way.

When comparing a steel between companies/makers, consider these factors.

Also, my experience with CPM-3V in my Survive! GSO-10 is quite positive - holds an excellent edge and resists chipping even on metal-to-metal impacts. I can't remember the hardness though...
 
The Koster knives I've used (Bushmaster and several Bushcrafters) all held up well to the woodworking I do. I've used a variety of North American wood from the northeast (both softwood like pine, hemlock and cedar and hardwood including cherry, soft maple, walnut and other "softer" hardwoods) and I have not had any problems with chipping. Dan seems to grind his scandi blades uniformly and the flat-ground Bushcrafter I have is rather wide behind the edge so it's not anywhere near filet knife thinness. It may have something to do with the edge stability. All I can say is that if he heat treats to 60, it works for me without babying it.
 
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