Knife Toolsteels... What Do We Really Know? An Earth-Returning Counterexample
- kaleokahu Jul 31, 2011 09:45 PM
Inspired by discussion in another knife thread about esoteric very hard toolsteels cladded with softer ones, and the history, uses, ramifications, and relative advantages and disadvantages of this, I've been thinking all weekend about this fancy steel business. How it is or isn't germane to good kitchen knives--at all pricepoints.
Much of the weekend I was waving a large chainsaw around. I had a truckload of mostly hardwood logs dumped (about 5 cords worth), and I needed to buzz it up into rounds for splitting. Although my Stihl saw had only a 28-inch bar, several of the logs were about 36 inches in diameter. A rough calculation Sunday night discloses that in cutting this load into rounds, I likely cut 250 times all the way through logs averaging 18 inches in diameter. By the time I was through, the chain was just barely noticeably duller than at the start, but the teeth (about 50 ittybitty L-shaped devils) were still cutting very precise chips and chaff. I could probably have made 500 cuts without the blade becoming dull. It remains sharp enough tonight to cut my fingers and chaps.
Now then, for comparison, the masters test for the American Bladesmith Society includes a cutting test through a *softwood* 2x4 with 15 inches of edge. Twice. That's one of the most rigorous edge-retention tests in all of knifedom--7 linear inches of cut. Compared with about 4,500 inches through mostly hardwood (actually, a lot more that that if you calculate the cross-sections).
I'm not 100% sure of the alloy in my Oregon Chain Co. chain, but I know it's not laminated VG10, or something like "SuperChrMog1550SVG". It must be cheap to produce, and I can testify it's easy to sharpen. If I had to bet, it's a steel called L6, or a variant of that steel. It's been around for a very long time, used in fine woodcarving knives, lathe tools, sawmill blades, chisels, you name it. I like many knifemakers have made knives from L6, because it's plentiful and cheap. And cuts and resharpens... like a chainsaw.
This got me thinking about what we (knife nerds and others here) REALLY know about the steels from which knives are made. Is it what we read? Is it what we've been offered to read by those in marketing of blades made of esoteric and proprietary steels? Is it in the anecdotal accounts by other users? Is it our own "hands on" experience with whatever steels are offered in retail blades at any given time? What rigors or systematic cutting tests have we really put our own blades to, and how many different steels/heat treats make up our experience base? What attempts--really--have we made to try the "lesser" steels like L6, or to canvas the field of mundane steels?
What I'm suggesting here is an open-eyed re-examination of the epistemology of sharp, and the role that "fancy" steels have to play, really.
Probably one place to start would be to look at the steel used by people who cut meat all day long -- butchers or workers in meat packing plants. I'd bet their knives are made of some pretty simple steel. I've seen some really old ones that were "worn" down to a fraction of the original width by years of sharpening.
As with most things, people are convinced that the more they pay for something the better it is.
As with many things, knives are a two sided coin, and sharpness, the ability to obtain and hold an edge is one side of the coin. I've talked in the past about my grandfather and his old butcher knives, how I remember as a kid watching him grind the edges on a manually operated tredel style stone that was probably 30" in diameter and 3" thick. How he honed the edge and then used the steel and a leather strop in the butcher shop to keep them sharp all day, while cutting meat. I don't recall how wide the blade was when they were new, but now they look like fellet knives from the repeated sharpening. I still have them, although they are never used. They are carbon steel, not stainless, and they are stamped not forged, I know one has Dexter on the wooden handle. These knives were tools of the trade back in a time when few could afford pretence. They were utilitarian, the best steel for the job at hand and the best price possible for the tradesman. A butcher couldn't afford a fancy forged knife with full bolsters and blackwood handles and nickel rivets. They needed knives that were sharp and easy to sharpen so they were always at their peak cutting performance. Can you imagine the plight of a butcher trying to cut a piece of meat with a dull knife as his customer is peering over the counter? I doubt my grandfather was much of a metalurgest, he just bought the most utilitarian knife available that he could afford.
The other side of this coin is Today's Kitchen, not my grandmother's kitchen, she got the butcher's knives after my grandfather couldn't use them anylonger. But today's upscale kitchen with granite counter tops and touchless faucets, multi thousand dollar ranges and french door refrigerators, Kitchenaid Pro mixers and oh yes, a block full of shiney stainless steel high end knives. I don't believe for the average cook the metalurgy of the blade plays much of a roll, it's just is it easy to maintian and does it look nice. It may also help if it has a mysteries of the Orient kind of name. I don't believe there are many who understand the metalurgy well enough to make a purchasing decision based on that information. Because of my other interests I may know a little but most of it does not apply to knife blades or at least I can't make that connection.
I probably won't be able to address every point you made in a single post. But here are a few of my thoughts.
- I know the steels I've used extensively reasonably well. A bunch of other steels, I know to some extent through sharpening. Then there's admittedly some hearsay (I try to make it clear when I'm just repeating what I've been told), some conjecture and extrapolation (for example, I've sharpened enough steels that use vanadium to know that it tends to make knives resistant to abrasives and thus harder to sharpen - so when I see a steel that is tempered high and uses a lot of vanadium, I can gather that it will be slow to sharpen even though I haven't used said steel before). This admittedly leads to an imperfect understanding of steel properties. But it's better than nothing.
- Some of the steels you are thinking of as esoteric may only be foreign. In other words, I may shoot the shat about powdered metal steels (e.g. zdp189, cowry x, sg-2), carbon steels that are allegedly difficult to work with (e.g 52100), and expensive new mystery steels (e.g. whatever the Konosuke HD is made of) - these steels are genuinely esoteric. But if you look at my own knives and many of the ones I recommend, the steels are hitachi white and blue carbon steels. AFAIK, these are more or less traditional carbon steels in Japan. What I love about Japanese knives really boils down to their geometry (though the steel has to support that geometry).... but it makes sense that if you're going to buy a Japanese knife, you might expect it to come in a steel that is less well-known to metal workers on this side of the world.
- I believe that test for the American Bladesmith society is a test of toughness - you are only allowed to chop, not whittle. Right? If so, that would be a very different test of a steel than sawing through the same block of wood. The challenge is to make a blade that can perform well at the other tests (often requiring a fairly fine edge) but also not chip or crumble with hard impact against wood.
- It is not only possible but nearly certain that there are tool steels out there that I've never heard of but can make a fine knife. Some of these tool steels may even be quite affordable. But, I'm not so certain that we can extrapolate how a steel will perform as a kitchen knife from how a steel performs as a chainsaw blade. For one, IIRC a chain saw's teeth are sharpened to fairly obtuse angles on one side only - like scissor blades, in a sense. An edge of that shape will tend to be pretty durable - I'm not surprised your chainsaw doesn't dull quickly. For a steel to perform the way I want it to on a knife's edge, it must be able to support an edge of under 30 degrees included and still have good edge retention without getting too chippy. Also has to have a fine grain structure so that it sharpens the way I want it to. Would L6 (or whatever your chainsaw blade is made of) meet these criteria? Truth is I don't know. Some steel qualities are more important for an obtuse edge cutting at high speed while others may be more important for an acute edge cutting at much lower speed. But there are also plenty of steel qualities that both types of edges have in common, ideally.
That's it for now. See yinz later.
Yeah, that's a lot to comment on. My little contribution is that custom kitchen knife makers are interesting to follow. Pierre Rodrigue uses a lot of different steels and they are often in a good position to evaluate what steels work better and make better knives for kitchen use. Harner and Rodrigue use cpm-154 a lot now, but in the past they probably used something else and decided to ditch it for some reason.
Devin and his son Larrin were long time advocates for AEB-L before anyone was making kitchen knives out of the Swedish razor steel. So I can see your point about path dependency and the need to look at things anew. Their advocacy has led to that steel becoming a favorite for some kitchen knife makers now -- but it took some time and someone willing to start making knives out of it that people could then comment on.
52100 (old ball bearing steel) isn't a fancy steel and is becoming a favorite it seems with custom knife makers too. Kramers carbon line is out of it, and I am getting two knives custom made out of it.
The fancy powdered stuff seems to be the rage with big-name knives and SG-2 is all over the place. I bet that passes at some point and they move on to a new technology in 5+ years.
But aren't there other considerations? I read on zknives that 52100 wasn't available in bar stock, so it seems that other factors can limit how used they are for making knives. Now that it can be obtained in bar stock, people are using it more.
Just some rambling thoughts.
kaleo, are you deforesting one of the islands by yourself? That sounds like a lot of work, my friend! :-D
I think I understand the motivation behind your questions. I wish I had a better understanding of why people (& companies) choose to do what they do. Alas, my best realization is simply this:
People are SO WEIRD!!
A lot of the "why" behind product decisions comes down to familiarity. Ownership-type mentalities like stability. So you get resistance to new materials, or processes, or "features" if they deviate too far from what's been successful in the past. When new things start to become accepted, the old things are relabled as outdated & the new things become the familiar. Marketing-type mentalities like to make their item stand out, so you get things like less-than-ideal stainless steels being used where carbon steels excel. Or maybe a nice layered and/or hammered effect to stand apart from the crowd.
Then you start to have technological additions. New tempering methods to existing stainless. VG-10 (just one in a line of VG steels) to replace "high-carbon" stainless. Powdered metalurgy (PM) to replace smelted metals. Ceramics to replace steels all together.
I know that you are already aware of these cycles & tides of human nature & product development. I guess I'm just editorializing to your questions. Humans have always been fascinated by promise of more. Whether it's a 14th century charlatan selling religous "relics" that he dug up from a common gravesite, or a 19th century travelling barker selling herbed alcohol as a miracle "cure" in a bottle, or a 21st century infomercial promising longer life from a pill, people want to believe they're in on the secret. IMO, that's what drives the plethora of choices we face today in many product lines.
Not terribly helpful, I know....
Now, regarding your example of chainsaw vs knife blade to cut wood....
I think a better analogy might be taking a single itty-bitty L-shaped saw tooth & mounting it onto a steel bar, then taking that new tool & trying to cut thru two 2x4s by hand with it. When you gang up 50 of these teeth in an infinitely continuous line, then add 4-1/2 HP of motive force behind it & 28" of leverage, you've got a lot of little scoops each shaving a thin layer of material from a fresh surface. By comparison, a single narrow edge being swung by an arm may be only generating 0.1 HP (complete WAG here, based on a fit cyclist generating 0.5 HP using the largest muscle groups in the body), cutting across many fibers simultaneously rather than planing material, & hitting different areas of the wood each time. The lack of power & lack of a continual supply of new edges, along with the blunting force of burying the knife's edge with momentum-stopping blows, makes the comparison unbalanced. (Isn't the knife blade then supposed to cut paper? Would a used chainsaw tooth be able to?)
Do I have a better analogy or test to offer? Sadly, I do not. :-(
I can think of other scenarios, like using a tailpipe cutter wrapped around a limb. Those edges may not dull as fast, but then you have more edges sharing the cutting work.
I don't know....
Maybe I'm just thinking out loud again....
I like your insightful musings. I think the psychology of marketing explains a lot. I especially like your "ownership mentalities" reasoning. Thanks. We live in an age where most folks must have new, therefore lose touch with the old, and therefore lose the perspective to judge between the two.
But I will quibble a bit about the teeth and horsepower distinctions. If 50 teeth together cut 4,500 linear inches of log, I think it's fair to say that each cut 90. Because the teeth alternate L and R, if instead of 50 you had one of each on one chain, it would still cut a *lot* of wood.
Somewhere in my survivalist/woodsman junk I have a "manual chainsaw". It's a short length of chain with forward- *and* backward-facing teeth, strung up with parachute cord and toggle handles. Doesn't sink through wood like a Stihl running at 12K rpm. But it cuts up to 6" logs and branches surprisingly easy. In both the motorized an manual cases, each tooth is cutting across many fibers simultaneously.
I'll see if someone can spot-weld me up a one-tooth-knife and see if I can drag it through a 2x4. Should be good for a laugh.