cpm3v versus infi

wnease

wnease

Joined
Apr 22, 2004
Messages
878
Hey, i'd like to hear experienced opinions on properly treated cpm3v versus infi, not a lot of metallurgical charts giving the charpy or abrasion resistance on infi
 
I've only been "fiddling" with CPM3V and INFI for about 2 years now ... hopefully folks will come by with more experience.

Frankly, I'm pretty happy with both. On the 3V side, I've used Fehrman knives and a number of customs (maybe 7 knives in all, from EDCs to two choppers). On the INFI side, I've got quite a few Busse knives.

Both are excellent performers for me, whether chopping or slicing. Both retain their edges for a long time. I am NOT the world's best sharpener, by a long shot! I find it easier to repair INFI edges than 3V edges, whether I'm steeling them back into place or re-sharpening. Haven't had much experience (yet) with completely re-creating an edge on either a 3V or an INFI knife ... it just hasn't come up yet.:)

Which edge lasts longer? For me, it's INFI, but the difference is not great.

I have more knives in INFI because I like the aesthetic, I like the handles, and I like the people.:)

The differences are not great. Go with a maker you trust and you'll be happy.
 
thanks oldphysics, i am a maker and have an analysis of infi, which is quite similar to the A8mod i use on some big blades. The 3v should be harder to sharpen with the vanadium so high, but should also stay sharp longer and being powder steel should have higher toughness for a given hardness and carbide content (though 3v will have a higher carbide content, infi is pretty low on carbon)

When i see 3v not performing better than just about anything i am suspicious of the heat treat

were the edge angles and thicknesses similar on the knives? Busse edges are thick compared to most of mine, significant effect on edge holding
 
i don't get to use search, but google helped me find some old stuff here on the forums...3v has had a very poor reputation, but the "secret and magical" heat treatments may be a major factor. many of the edge failures had 15 degrees per side edges, aren't busses a bit steeper?

Has anyone used it heat treated by paul bos?

has anyone tried S7 versus infi?
 
wnease said:
thanks oldphysics, i am a maker and have an analysis of infi, which is quite similar to the A8mod i use on some big blades. The 3v should be harder to sharpen with the vanadium so high, but should also stay sharp longer and being powder steel should have higher toughness for a given hardness and carbide content (though 3v will have a higher carbide content, infi is pretty low on carbon)

When i see 3v not performing better than just about anything i am suspicious of the heat treat

were the edge angles and thicknesses similar on the knives? Busse edges are thick compared to most of mine, significant effect on edge holding
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Agreed. My Busse choppers mostly have very thick edges ... and that's definitely an important contributor to its edge holding ability. I do have a number of thinner edged Busses, especially some EDCs, and I'm still very happy with their performance as EDCs.

I've moved my Fehrmans along, not because I don't like the knives, but because I just can't get comfortable with the grips. As I recall, the edges were pretty thick on those, as well.

I'd suggest corresponding with some of the makers around here who have worked with 3V. I recall Dan Koster doing work with that steel ... and I know others have (I just can't recall their names at the moment). I'd trust makers far more than us mere users -- they're the ones who really put the steel through its paces. Kevin Cashen would be an excellent person to talk to on such a subject, I'd guess. And of course, Jerry Busse when it comes to INFI.

As to your INFI analysis. Although I don't have the composition laying around my library, I know it is 'out there' and really no secret. When I first noticed INFI, I was going to take a blade in to some friends of mine so we could do analysis, until I noticed that the composition was public knowledge. It's a nitrogen-based steel, as I'm sure you know.

I actually am a physicist myself, a solid state physicist (and optics/lasers). Steel is a fascinating material ... no matter how much you THINK you know, there's always something new just waiting to be discovered. Small differences in composition, forming, heating treating, etc. can make remarkably large differences in behavior and performance. I wish you luck in your continued search for knowledge.:thumbup:
 
Busse makes knives also in S7 with his in-house heat treat. S7 is soft compared to Infi and Infi has similar if not greater ductility. Im also not sure if A8Mod is close to Infi. I think the "small"" differences are significant in Infi's case...
 
wnease said:
i don't get to use search, but google helped me find some old stuff here on the forums...3v has had a very poor reputation, but the "secret and magical" heat treatments may be a major factor. many of the edge failures had 15 degrees per side edges, aren't busses a bit steeper?

Has anyone used it heat treated by paul bos?

has anyone tried S7 versus infi?
Click to expand...

If I understand your geometry-question, I believe most of my Busses are closer to 20 degrees per side. There have been recent cases where the edges of Busse knives were thinned to the point of uselessness, but it was tough to tell just how far the edges had been thinned (the poster was having trouble measuring and reporting the angles ... not a native english speaker).

I actually don't know if Mr. Bos has treated 3V.

Mr. Busse has experimented with S7 and has his own, modified version of that steel [INCORRECT: Busse uses standard S7 coupled with a proprietary heat treatment protocol]. He uses it to make knives in a sister-company (I think it's the SwampRat brand that uses his modified S7) [INCORRECT: these are ScrapYard knives.]. If I'm correct, you can check out the separate ScrapYard forum itself ... for answers to your question. The "general opinion" amongst Busse fanatics is that S7 is great, but not quite as good a performer as INFI (of course, one must always be careful when receiving the "general opinion"). I have a number of ScrapYard blades [doesn't everyone?], choppers and EDCs, and the edges don't stay sharp as long as my INFI blades.
 
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The S7 Busse uses is standard S7. He calls it SR-77 because of his heat treat. The knives are by Scrapyard Knives.
 
wnease said:
i don't get to use search, but google helped me find some old stuff here on the forums...3v has had a very poor reputation, but the "secret and magical" heat treatments may be a major factor.
Click to expand...

Sorry, should have also addressed this.

As Kevin Cashen will tell you, there's nothing "secret and magical" about steel or the process of making and forging it. However, some processes are more sensitive and complex than others. Heat treating is used to relieve or set stresses/strains in the steel, often by altering its crystalline structure or moving the grain boundaries. Manipulating the temperature in a sensitive way within a large piece of steel is just not as simple as people think it is. Also, there's no real incentive for someone who has spent many years developing new heat treating protocols to share it with everyone. These two facts, alone, explain the layman's belief that heat treating is "secret and magical.";)
 
regarding the secret heat treat... if a steel has the specs that crucible says it does, but makers find it below expected performance, i suspect the secret heat treat to be defective... crucible sends cpm steel with the melt # on it, very consistent products

some makers (and testers) have outstanding performance with thin hard 3v blades, some have poor performance with softer thicker edges in the same steel... i would think we blame heat treat in the latter case but still looking for hard facts
 
wnease said:
Has anyone used it heat treated by paul bos?
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I haven't. I beleive Jerry Hossom has made many knives out of 3V and had many of them heat treated by Paul Bos and had very good reported results.
 
Heat treat and the edge you put on the blade account for a lot. Although crucible provides their specs for heat treating 3V you will get variations in performance from the same steel heat treated by Paul Bos (better results I would think). Email me and I'll send you a link to read up on.
 
As mentioned, Jerry Hossom would be a good source of information about 3V. He has made a number of blades of 3V, and I believe he has Paul Bos do the heat treat. See him at the "other" forum.
 
I agree that 3V and infi are close. Heat treat obviously can make a big difference. I do find 3V harder to sharpen. One difference I've found in the field is corrosion resistance. CPM 3V doesn't stand up as well to corrosion as infi, at least in my experience.
 
I've had great results with both. I've only gotten INFI from Busse knives (obviously), and have only used 3V with Fehrman knives. I think 3V holds it's edge longer for cutting, I haven't yet been able to test the 2 for chopping. Using DMT diamond hones and ceramic stones, they are both easy to sharpen to me.
 
sodak said:
I've had great results with both. I've only gotten INFI from Busse knives (obviously), and have only used 3V with Fehrman knives. I think 3V holds it's edge longer for cutting, I haven't yet been able to test the 2 for chopping. Using DMT diamond hones and ceramic stones, they are both easy to sharpen to me.
Click to expand...

+1....... My Fehrman blades have held there edges longer then INFI but you really have to be paying attention. Both are amazing steels, cant go wrong with either.

I just chopped out an entire pepper tree with my Fehrman FJ, Probably 4 hrs of chopping, still could shave after:thumbup:
 
sodak said:
I've had great results with both. I've only gotten INFI from Busse knives (obviously), and have only used 3V with Fehrman knives. I think 3V holds it's edge longer for cutting, I haven't yet been able to test the 2 for chopping. Using DMT diamond hones and ceramic stones, they are both easy to sharpen to me.
Click to expand...

Same with me.

Thanks, Vassili.
 
Teh maker who goes by "Longrifle" on BF also makes knives in 3V, he might have some thoughts
 
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