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The Composition of Infi and What it Means

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I have many AUS8 knives and have had two IIRC made of AUS8 mod and INFI is definitely more rust prone. Is that because of heat treat or an effect of small amounts of other elements?
I see now the err of my thought haven't been myself including reading comprehension.
A8 as in A2 not AUS8...
 
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OP, I like reading your posts but I stopped this time before reaching the end. I am a simple consumer, I could care less if Infi was made from ground up unicorn horn and quenched with mermaid tears from the Bermuda Triangle. What I do like is the guarantee on the Bussecombat website. Not too many companies or custom makers would encourage you to use the knife as hard as you like and post it on their website for all to see.

“All Busse Knife Group blades are guaranteed for life against any and all unintentional MAJOR damage......Busse Knife Group encourages extreme usage of our blades as they are without question "The Toughest Knives in the World". We have no rivals. You can use a Busse Knife Group blade as hard as you like and our warranty has you covered.”

It’s a nice warrantee and there will always be a better steel in the future or even right now. Interesting designs but most are not for me. I only have a park ranger and it is good to go for my purposes.

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Valid point. For you, warranty is what is important. So for you all this talk about slight differences in steel is irrelevant, and that is OK. Larrin and his site are more for steel nerds who like to agonize about minute details of steels and heat treats and that is OK too. I like what Larrin does, I think it enlightens all of us and makes the community more knowledgeable. I find religious like following of some members silly. There is no magic in steels or heat treats, all can and should be explained. After all you wouldn't attribute any magical qualities to a phone or TV, but knives, swords and the like somehow get this mistique.....
 
It is very difficult to get two exactly same blades in different steels. This is why testing is done with specific pieces in a controlled environment. A custom maker can ofcourse make two knives that are close, but Infi is not available.

There are many custom makers on this forum, I am sure if you really want it you can find someone to make you a custom out of A8 Mod or any other steel that is available to them.
 
ace said:
Valid point. For you, warranty is what is important. So for you all this talk about slight differences in steel is irrelevant, and that is OK. Larrin and his site are more for steel nerds who like to agonize about minute details of steels and heat treats and that is OK too. I like what Larrin does, I think it enlightens all of us and makes the community more knowledgeable. I find religious like following of some members silly. There is no magic in steels or heat treats, all can and should be explained. After all you wouldn't attribute any magical qualities to a phone or TV, but knives, swords and the like somehow get this mistique.....
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In this particular case (INFI), I don't think it's "mystique" at all. I've personally carved a refrigerator up with it. I've seen a car literally cut in half with it, seen it pounded into asphalt "just because", etc. All with no more damage than a few spots of slightly rolled edge.

Busse doesn't just put that type of warranty out there for no reason. No, the knives are not magic. They are not infused with unicorn horn and quenched in dragon tears (to my knowledge).

But, INFI IS damn tough, and it holds an edge cutting common materials for a long, long time. It holds an edge cutting uncommon materials too. ;)

Waaaaaaaaay back in the day Mike Turber and Jerry Busse traded off cutting small sections of rope with a Basic 9 and a Trailmaster. The Basic 9 seemed to them to be getting more polished and sharper as they kept cutting. To my recollection, they only stopped because they ran out of rope.


ace said:
It is very difficult to get two exactly same blades in different steels. This is why testing is done with specific pieces in a controlled environment. A custom maker can ofcourse make two knives that are close, but Infi is not available.

There are many custom makers on this forum, I am sure if you really want it you can find someone to make you a custom out of A8 Mod or any other steel that is available to them.
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I have never seen any knifemaker on here producing knives in A8-Mod. It doesn't seem to be all that popular for some reason, or maybe not readily available to them.
 
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Larrin was not discussing knives, or comparing knives. He is testing, analyzing and explaining steels and metallurgy. It sounds like some people don’t see the difference.

I am not doubting what you saw and did, but most of these are not what a regular knife should do. Knives should cut well and depending on what you were cutting you would design a knife accordingly.
 
“All Busse Knife Group blades are guaranteed for life against any and all unintentional MAJOR damage......Busse Knife Group encourages extreme usage of our blades as they are without question "The Toughest Knives in the World". We have no rivals. You can use a Busse Knife Group blade as hard as you like and our warranty has you covered.”

Warranties are paid for by the buyer of the knife. Busse is no exception.

"The Basic 9 seemed to them to be getting more polished and sharper as they kept cutting"

I like Busse knives too but do you think Infi doesn't act like steel? I can see it to a point as it abrades the steel from where it was sharpened but this is hyperbole and not some new or unusual super technology. It's a knife edge and works like other knife edges.

I've seen this same A8(mod) = Infi subject here on the forums turn out bad numerous times in the past and go on and on. Is there something unpalatable about Infi being A8(mod) ? It's obviously a good steel for what it does well. It's not the toughest or most wear resistant but it's a great steel well balanced for knives meant for hard use. I'vesaid before that the best thing about Busse isn't "Infi" but the great lengths they go to seeing the knives are consistently heat treated and built very very well from batch to batch. That doesn't come by accident nor cheaply. So it's A8 (mod). :)

Joe
 
Here we go. To start out, a meaningful metallurgical difference and a technical classification difference are not the same thing. Metallurgists and steel companies carefully tune their steel compositions both within and without grade classifications and that is different than determining what classification it fits in. When I say that Infi is A8 mod I am not making any claims about whether or not a 0.1% Mo difference is meaningful in terms of properties.
1050 and A8 mod are not equivalent classifications. The category of steel is not 1050, it's 10XX. The 10 refers to a carbon steel which can have intentional additions of only carbon, manganese, and silicon. There are many different 10XX designations for several reasons:
1) Carbon has the biggest effect on steel properties
2) The simpler the steel the more the carbon matters. If 10V has 2.55% carbon instead of 2.45% it matters less than comparing 1045 to 1055.
3) There are historically agreed upon manganese contents for different 10XX grades despite only specifying carbon content. Which means that some small changes in the carbon designation are not actually because the carbon needed to be different.
4) Tradition

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The tool steel designations, ie A2, D2, O1, etc are a little bit broader categories. For example, there are two standard carbon contents of M2: 0.8 and 1.0. They are both called M2. W2 can have a wide range of carbon, 0.7-1.3. It is all called W2. We don't have W270 and W295. If a company came out with an A2 steel with 1.1% carbon (outside of the specification), they would probably call it A2.
A8 mod or Chipper Knife steel also has some allowance for composition, Uddeholm targets 1.5% Mo and Latrobe targets 1.3% Mo. If the EDS measurement of Infi is accurate and the company is targeting 0.9% or 1.0% Mo that is still A8 mod. The difference may be important or meaningful but that does not mean that the classification changes.
In my post I said, "At the very least it is in the same 'family' of A8 mod-like steels," I didn't say that it isn't A8 mod. If the EDS measurement was somehow dead-on and the target carbon content of Infi is 0.6% instead of the typical 0.5%, or some significant alloy addition was missed, then a case could be made that it doesn't fit the A8 mod specification. That would be a stretch but the pedantic among us might make a case. I took this as an opportunity to talk about families or categories of steel, because adding 0.5% Ni to something doesn't change it from D2 to unobtanium. It may change the properties somewhat. But we don't have space alien technology. We have to understand what a meaningful difference is, how different it is, whether that matters for a grade classification, and whether that matters for people understanding what Infi is. If the EDS measurement was off by a significant amount and it is technically outside of some agreed upon specification of A8 mod, then we would say that it is in the same family but is not technically A8 mod. I'm not sure that it would matter, but it is unlikely anyway. The information we have says A8 mod. But there's a small chance it isn't.

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Megawatt308 said:
OP, I like reading your posts but I stopped this time before reaching the end. I am a simple consumer, I could care less if Infi was made from ground up unicorn horn and quenched with mermaid tears from the Bermuda Triangle. What I do like is the guarantee on the Bussecombat website. Not too many companies or custom makers would encourage you to use the knife as hard as you like and post it on their website for all to see.
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The design of the knife is much more important for performance than steel selection, so if we are going to argue about what’s important we should start there. I also think ending child trafficking is more important than deciding which $500 knife to buy. But I started this thread anyway.

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I'm far from a seasoned heavy knife user, but is there anyone else using A8 mod steel? I've not owned Infi before but I did order my first recently. I think "infi" a marketing thing but if the steel works, it works... for me at least. I think nerding out on stuff is fun as I like learning new things. I would prefer they call it A8 mod if it is but I don't think they're the first, like tru-sharp from case which is supposedly 420HC if I have my reading right, to call a known steel something else. Didn't cold steel do something similar with carbon V so they could swap in various steels of very similar composition, though different steels none-the-less, without changing their spec sheets? Maybe that's a lot of speculation, even more than the Infi discussion.

Seems busse does a great job HT'ing and maybe that's where the fancy name comes in. It makes it seems better than saying "we have the same steel as other premium knife makers but know how to HT it better and our designs are BA." I'm actually more fond of the SR101 which is supposed to be 52100... and I wish they would just call that 52100 also. Well known as a great steel if you can get the HT right.

What I have wondered and what doesn't seem to be the case is if busse is making some kind of proprietary metallurgical modifications like making/formulating steel in-house. Seems like he has the education to do it from some of the description of his academic life. Seems like some of the cost of the knives could have accounted for such a high cost of entry to infi but there is a lot of engineering going on with the knives we don't see elsewhere with the use of fullers in the blade flats and fullers in the bevel (think they're called fuller in kuhkri's, corrugated bevel tech for busse). Considering the added work, some of the price is justified with those added features, IMO. It's like a nice HI kuhkri (big hunk of steel) but with some nicer materials at a slightly increased price and more designs available.

Larrin, keep on bringing the science. We sure need more objective thought in the world.
 
A8 Mod is used industrially for chipper blades in tremendous quantities. The major manufacturer of those in the US is in Simpsonville, SC. They make 90% of the domestically manufactured blades for chippers. They have so much they added onto their facility to be able to store it all. The thinnest I saw was 3/8" thick, but it wouldn't surprise me to see 5/16" or even 1/4" there. It is out there, but not available from the usual sources knifemakers use. Whatever steel Busse uses, I'm sure they buy it in tonnage quantities, perhaps making steels available to them that most knifemakers aren't able to get.
 
me2 said:
A8 Mod is used industrially for chipper blades in tremendous quantities. The major manufacturer of those in the US is in Simpsonville, SC. They make 90% of the domestically manufactured blades for chippers. They have so much they added onto their facility to be able to store it all. The thinnest I saw was 3/8" thick, but it wouldn't surprise me to see 5/16" or even 1/4" there. It is out there, but not available from the usual sources knifemakers use. Whatever steel Busse uses, I'm sure they buy it in tonnage quantities, perhaps making steels available to them that most knifemakers aren't able to get.
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I think from my perspective it's just that I've never seen another knife using A8 mod, so even if that is what they are using it still makes it a bit unique. They could even call it A8 mod instead of infi and it would be unique in the knife world, I think. Just my opinion.

Thanks for the lesson on industrial use of the steel.
 
Larrin said:
The design of the knife is much more important for performance than steel selection, so if we are going to argue about what’s important we should start there. I also think ending child trafficking is more important than deciding which $500 knife to buy. But I started this thread anyway.

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Indeed
The old timer woodsmen had knives with good designs but crappy steel
They used their knives more than 99% of the people on this forum
 
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