A medium bounds for performance : chopping

[Jerry Hossom]

That's the ABS competition which excludes stock removal (nonforged) knives. The Professional Cutting Competition is open to all knives and all knifemakers. ABS members also compete in the PCC.

 

[hardheart]

my bad. are the tests different in the other competitions?

 

[Cliff Stamp]

Clearly, you are claiming greater skill and understanding of edges than the best of the knifemakers who are competing in these competitions.

No, I said the cutting requires great skill, mainly precision, cutting moving ping pong balls and such is no test of a knife, just of the maker. I chopped almost a thousand times with the very inexpensive axe noted here before it would stop shaving and there was no deformation of the edge. The edge angle is also as noted very acute, so cutting one 2x4 does not impress me as a test of durability.

If you want to do something which is demanding on a blade then limb out a tree which died in a low light area and cut the limbs in sweeping cuts towards the root. That is the most stressful wood cutting which can be done and is many times more demanding that cutting a thick piece of production lumber. And yes I do that all the time with the knives noted and there are lots of pictures of it in the reviews.

Tai Goo is a wonderful bladesmith. He does not make competition cutting blades.

I fail to see the point of this, only the people who make those blades have knives that can perform? Do the edges on Goo's knives roll and deform readily? He makes a large number of large bush knives, those are work pieces correct? What about all the people working with 5160 and other similar steels, all of their edges are fragile?

If you can do that 3V bending task with something else, do so and take photos.

That is really silly for the reason I noted, all I have to do is find a soft stump and the wood will just bend and the knife will not even flex. I will keep an eye out for one.

52100 has 1.0-1.1% Carbon. 12C27M has 0.52% Carbon. 12C27M has 14.5% Chromium. 52100 has 1.5% Chromium. Don't look much alike to me.

In solution in austenite both have the same amount of carbon thus they have similar hardening responce. They have a similar carbide structure, very fine carbides with a very low volume. They are both low alloy, very low carbide steels, among the highest edge stability steels. Read Landes book for more information on how to compare steels on the basis of carbide volume and how this relates to edge stability which is the ability to resist chipping under loading on the scale of the edge width (microns). You will note that when he classifies steels it is not on the basis of stainless vs nonstainless but on hardness and carbide volume.

Verhoeven compared and found the Sandvik steel had better wear resistance that similar low alloy carbon steels because at similar hardness the Sandivk steel has a bit more fine chromium carbides. Verhoeven classed 12C27M/12C27/13C26 as all pretty much the same (ideal steels for knifemakers) and included other steels in there as well like AUS-4 as they all have similar properties; enough hardness to resist deformation, a very fine carbide structure to prevent tear out, and enough free chromium to give high stain resistance.

Of course if you do not need corrosion resistance you are better off without all that chroimum and if you want more wear resistance then you look at high tungsten versions of W1 and similar steels. You lose edge stability then though and have to thicken the edges to keep them sharp so they are more for either lower cutting ability or to hold a blunter edge for longer.

That's the ABS competition which excludes stock removal (nonforged) knives.

Is the ABS cutting competition so much less demanding on the edges? They also cut cans, ropes, chop 2x4, etc.

-Cliff

 

[HoB]

Hardheard, I don't think the difference in the tests is the point here. The point is more that the use of CPM-3V, CPM-M4, etc. is precluded in the ABS championships, as they can not be forged (well, not really, that is).

It is like claiming that the Mini Cooper has won all races and not to mention that Ferrari's, Lamborgini's, F1 cars etc. weren't allowed to compete.....(not the best example, but I think it makes the point).

 

[Jerry Hossom]

Cliff, I think you're blowing smoke and at the same time belittling the accomplishments of highly competent knifemakers and knife users. Hitting a rolling ping pong ball may require user skill, but cutting it rather than just deflecting it requires a very fine edge as does the paper towel ring cut among other tasks. I never said cutting 2 x 4's was particularly demanding (unless you do it in under 5 seconds which is what high performance edges in the right hands are capable of) A hardwood dowel is a challenge for edges that can also do the fine cuts in the contest. You say it is not. The top competitors in the PCC think it is. Who should I (or anyone else) believe?

Cliff, I believe you are cutting conifers. Unless it is yellow pine heartwood that is not challenging. Certainly, Spruce isn't very hard. Hickory or Osage Orange are challenging. Your claim that what you do is many times more stressful than what other people do to test their knives, especially in light of nobody being able to test the same wood as you test, makes for a hollow claim. Test something that everybody else can test, so they can assess and confirm your findings. That is what both the ABS and PCC competitions are all about, comparing the cutting ability of blade and user with others in the same tasks.

The person who broke the CPM-3V knife wasn't trying to bend a knife to 90 degrees; he was trying to break the knife and wanted to see what it would take to do that. So finding a rotten stump wasn't his goal. Breaking the knife was. He did, but it wasn't easy. Your assertion that was merely a ruse by using an appropriate stump is cynical at best.

I didn't say Tai Goo's knives weren't high performance knives, but neither you nor I have a measure of how good they are compared with the PCC knives. We know the ABS competition knives are quite competitive because of the ABS members competing in PCC events.

Landes' book is in German, so I'll not likely be reading it. Being in German does make it a handy reference source for you though, since there is no easy means of confirming your quotations of what he's written. Even so, you'll still need to produce some serious independent testing (performed in a place other than Newfoundland and reported in English) to sell the notion that steels in the 0.4 - 0.6% carbon range make superior knives.

 

[hardheart]

Hardheard, I don't think the difference in the tests is the point here. The point is more that the use of CPM-3V, CPM-M4, etc. is precluded in the ABS championships, as they can not be forged (well, not really, that is).

It is like claiming that the Mini Cooper has won all races and not to mention that Ferrari's, Lamborgini's, F1 cars etc. weren't allowed to compete.....(not the best example, but I think it makes the point).

I can't find specific results with knife data to see if there was a difference in performance. Even then, it's kinda hard to compare because the same pesron isn't using the same profile knife in different steels, even if the tests are the same.

I understand the car example, but it's kinda hard to see if it fits. If the Mini tripped the quarter in 14.2 seconds (completely fabricated, have no idea) on Friday, and a Ferrari ran it at 14 flat on Saturday, at two different owner enthusiast events, does it show clear superiority of the Ferrari or the driver?

I don't think you can just look at the winner's spot and say M4 is better. I'm not saying it isn't, but to me the validation of that would be edge angles and thickness numbers for the M4 blades to be shown, and that they are thinner than the winning blades of other steels. If you then take the other winning steels and thin them to the same point, they fail. Then you show you can use less M4 to do the same job, which is definitely better, to me. And imo, user skill does play quite a large role, so lots and lots of testing would probably be necessary to show just how much better the CPM M4 is.

 

[Jerry Hossom]

Hardheart, not all steels should use the same geometry. Each uses the geometry which best suits its structure and strengths. The whole purpose of the competition is that whatever steel you choose to use, you optimize the geometry of your edge to perform the cuts, and the cuts are sufficiently diverse to challenge any steel.

On the matter of user skill. It is true that results are biased by the skill of the user. (That is always true, no matter what knife you test.) That said, can you fairly evaluate a knife if it's not used by the most competent user you can find? I have always used expert filipino martial arts practitioners to test my tactical knives because they can push them to their maximum potential. All I would be able to do myself is a poor reflection of the cuts they can perform. Which best tests the knife? IMO, it's the user who can perform the most challenging cuts. That challenges the limits of the knife, not the limits of the knife user.

By contrast, how can you reasonably judge the evaluation that Cliff performed above? You don't know anything about the physical nature of the wood that was chopped or the skill and strength he possesses relative to others who might do the same cutting tasks.

I think HoB was referring to road racing, and the solution is to have the same driver operate all the cars or have all the cars driven by expert operators who will minimize the limitations of each car (i.e. get the most they have to offer).

Actually you can analyse this to death, OR you can just grab another nail and find out.

 

[Cliff Stamp]

Hitting a rolling ping pong ball may require user skill, but cutting it rather than just deflecting it requires a very fine edge as does the paper towel ring cut among other tasks.

What is the thickness and edge angle on the cutters? Is it significantly more acute than the profile I noted in the above?

Certainly, Spruce isn't very hard.

Not when it is live no, when it is dead and seasoned for 5-10 years and it splinters leaving actual sharp edges it is different.

Your claim that what you do is many times more stressful than what other people do to test their knives...

I noted that wood cutting described is more stressful than a static cut of a hardwood dowel because I have done both and know what edges are required for stability. This is not a claim, it is a statement of fact. I was also cutting dowels years ago so this is not something new.

It is also fairly basic physics because the dowel is much larger so the stress is lower and is a much more static cut whereas in the limb cutting the branches will bend and snap around the edge and after the first cut the edge will hit them off center.

To simulate that with a dowel cut, stick a bunch of dowels into a 4x4 at odd angles and then sweep them all off with one cut of the knife. It isn't clear to you that is much more stressful? Have you actually ever done the limbing work I described?

Your assertion that was merely a ruse by using an appropriate stump is cynical at best.

My assertion is that it is impossible to note how much the knife bent because part of the bend is of the wood. Therefore it can be done with any knife if you find the correct stump.

I didn't say Tai Goo's knives weren't high performance knives, but neither you nor I have a measure of how good they are compared with the PCC knives.

Why would you even assert that non-PCC knives are inferior anyway? Again, do you assert that the edges on his knives would easily roll and impact in use, yes or no? He uses the exact steels which you claim have that performance and he is known for very high performance cutting and sharpness.

Being in German does make it a handy reference source for you though, since there is no easy means of confirming your quotations of what he's written.

Landes speaks english, ask him. He is even on Skype so it will not cost you anything to talk to him. You can just email him either. Verhoeven's work is also in english and he supports the 12C27M steels as superior for knives for the reasons I noted. Of course all the guys forging using very low carbide steels whose knives run lathe martensite (which requires a low carbon content as plate will form otherwise) also make the same statement.

I don't think you can just look at the winner's spot and say M4 is better.

All that means is that it is popular. Would anyone even argue with 100% confidence that the winner would even change if you switched knives. It is also not the case that all follow the high carbide = superior line, Thom has noted outspoken makers who prefer low alloy steels such as one rather well known one who is collaborating with Spyderco (Schempp).

-Cliff

 

[Jerry Hossom]

What is the thickness and edge angle on the cutters? Is it significantly more acute than the profile I noted in the above?

Ask one of the participants. Are your edges convex?

Not when it is live no, when it is dead and seasoned for 5-10 years and it splinters leaving actual sharp edges it is different.

"Sharp edges" on wood has what to do with how hard it is to cut?

I noted that wood cutting described is more stressful than a static cut of a hardwood dowel because I have done both and know what edges are required for stability. This is not a claim, it is a statement of fact. I was also cutting dowels years ago so this is not something new.

No that is a claim. When it is witness by others who attest it actually happened it becomes a statement of fact.

It is also fairly basic physics because the dowel is much larger so the stress is lower and is a much more static cut whereas in the limb cutting the branches will bend and snap around the edge and after the first cut the edge will hit them off center.

You're comparing a hardwood dowel with spruce, and even then the edge has to also prove it can perform the fine cuts in the contest. Not an apt comparison.

To simulate that with a dowel cut, stick a bunch of dowels into a 4x4 at odd angles and then sweep them all off with one cut of the knife. It isn't clear to you that is much more stressful? Have you actually ever done the limbing work I described?

We need pics

Why would you even assert that non-PCC knives are inferior anyway? Again, do you assert that the edges on his knives would easily roll and impact in use, yes or no? He uses the exact steels which you claim have that performance and he is known for very high performance cutting and sharpness.

I did not assert anything of the sort. I simply said we don't know. His blades may be better than the competition blades. I and YOU don't know.

Of course all the guys forging using very low carbide steels whose knives run lathe martensite (which requires a low carbon content as plate will form otherwise) also make the same statement

.

"All of the guys forging"? Hardly. I also note that you have slipped from "low carbon" to "low carbide". Which is it? Is O1 Low Carbon/Low Carbide? Which is 52100 REALLY? How about CPM-3V? 0.8% Carbon?

All that means is that it is popular. Would anyone even argue with 100% confidence that the winner would even change if you switched knives. It is also not the case that all follow the high carbide = superior line, Thom has noted outspoken makers who prefer low alloy steels such as one rather well known one who is collaborating with Spyderco (Schempp).

That's complete nonsense! Since when is CPM-M4 "popular"?

There is absolutely NOTHING wrong with low alloy steels. There are some not so outspoken knifemakers who have proven low alloy steels are GREAT. There are GREAT low alloy steels, by anyone's measure. There just aren't any GREAT low carbon stainless steels. Stop switching terms, Cliff. It makes it look like you don't know the difference, and confuses others. Low alloy and low carbon are decidedly not the same things. Stainless steels are not low alloy steels. 52100 and O1 are not low carbon steels.

Does anyone know what steel is used in a Fiskars hatchet? Also, do they make knives?

 

[Knife_Geek]

Does anyone know what steel is used in a Fiskars hatchet? Also, do they make knives?

Fiskars as a brand doesn't I don't think But they own gerber so maybe in a sort of making by association type thing.

 

[Cliff Stamp]

Ask one of the participants.

I thought I did. I asked Ray Kirk awhile back, his edges are similar to what I use for my wood cutting knives though he used at that time a more complex triple bevel.

Are your edges convex?

They have the specific geometry I noted. They are sharpened flat at 8/10 degrees, the very edge is then sharpened at a slightly more obtuse angle 12/14 degrees as otherwise it will turn on sloppy cuts. This is all hand sharpening on waterstones. This last bit is thinner than the edge on most production folders, with the exception of the the Calypso Jr. and other such knives from Spyderco.

"Sharp edges" on wood has what to do with how hard it is to cut?

When spruce has become that seasoned that it violently splinters when it is cut, yes, it indicates it is significantly harder than live wood. Because it breaks violently it also makes it directly harder to cut because the blade moves through it an in fairly uncontrolled manner.

When it is witness by others who attest it actually happened it becomes a statement of fact.

It has been witnessed by dozens of people. I cleared a lot last year for a friend of mine and members of both are families were there on occasion and there are multiple pictures before and after of the cutting. My brother usually works with 4-8 other people, I can give you his cell number and you can call him at work and speak to his crew and verify that he and I actually do the work that is pictured in the reviews.

You're comparing a hardwood dowel with spruce, and even then the edge has to also prove it can perform the fine cuts in the contest. Not an apt comparison.

I am comparing wood I cut, which is more than spruce, there is also oak, maple, juniper, of various seasoning and I have cut many hardwood dowels statically and they are much easier to cut for reasons I noted. The lateral loads are much higher in limbing, this is why in the Axe Book, Cook even notes that you need a special axe to do it because it is so difficult. Anyone who cuts wood will tell you that is the most demanding thing and what I described (inverted shearing) will be called by many as outright abusive because it is so stressful as the limbs will bend and snap around the edge. The edge I described in the above will however still do that and it is so acute it can be easily sharpened on the low angle on the Sharpmaker. This is because all the knives I have for such use are low alloy steels with very high strength/toughness ratios.

Hardly. I also note that you have slipped from "low carbon" to "low carbide". Which is it? Is O1 Low Carbon/Low Carbide? Which is 52100 REALLY? How about CPM-3V? 0.8% Carbon?

They are low carbide/high edge stability steels. In general I would not consider carbon independently of the other elements for reasons noted. You can for example just increase the vanadium in the steel which will soak up the carbon rapidly and make a 1% C steel even unhardenable by conventional heat treatments so it will be high carbon and yet act like mild steel. I noted before, look at the carbon in solution, not what is the annealed steel.

Since when is CPM-M4 "popular"?

How many people use it in the competitions?

There are GREAT low alloy steels, by anyone's measure. There just aren't any GREAT low carbon stainless steels.

Ok, now why are the low alloy steels excellent aside from when they are also stainless? Why do you need lots of carbide in stainless but not in nonstainless? What is the flaw in Landes and Verhoevens methods and metallurgy which lead them to their conclusions which directly oppose yours?

Does anyone know what steel is used in a Fiskars hatchet?

I have asked, even phoned awhile back, still do not know. It is really soft though, 50-56 HRC, forged. The VTAC from ATC is having similar performance now. I have one run done will do another later, that is a low alloy steel, also very soft. The edge on that is more obtuse than the two axes previously noted, 15/20. I would take it down further but it is just way too much grinding.

-Cliff

 

[Broos]

OK, I'm getting a little dizzy over the repeated references to edge stability, and from my understanding it seems like it is overdone.

I can understand "edge stability" as an idea, as indicated here:

http://www.bladeforums.com/forums/showpost.php?p=4485405&postcount=39

Or here, with a graphical aid:

http://www.bladeforums.com/forums/showthread.php?t=344902&highlight=Roman+Landes
Even though there is not one mention of "edge stability" in the above post.

Seems pretty straight forward - that a very "scary" sharp, thin, polished edge (1 micron edge width) is much more obtainable with small carbide steels, and that they will maintain that edge better under PUSH CUTTING when the steel is small grained. It also seems there is something there that a high percentage of carbides will lower edge stability.

I take this to understand that any technical definition of edge stability would be the same as push cutting (only) edge retention - it will be defined by the test that measures it. Further qualified as push cutting edge retention at very sharp levels, so test only thin or acute edges that are capable of getting really sharp and then stop the testing relatively quick (at still high sharpnesses). Does Landes dimension or quantify "edge stability" in his book? If yes, can anyone explain how he does?

No reference is made in regards to how this would affect slicing, though Landes mentions that he would still use a large carbide steel if he wanted an aggressive slicer. So is the mention of edge stability warranted when slicing edge retention is the issue at hand? I assume not.

And does all that stand up to reason when looking at any steel? Does FFD2 contradict any of the assertions made? Very high carbide content, you know, and when pressed in the FFD2 thread the most Landes would say is that he thought AEB-L would be a better razor blade steel than FFD2. He did not contend it was a better knife steel.

And I know I'm stretching it with all the references to Landes, but if Cliff can, dagnabit so can I. And since he never corrects Cliff, maybe he won't correct me! And if he does, that's OK, too! I'm not trying to minimize his work, but it seems to me that this term may be being extrapolated beyond its intended meaning.

My point is, could not references to grain size, carbide size & percentage, and push cutting edge retention be better understood by more readers everywhere, than the obscure term of edge stability? Is the use of all these redundant or obscure terms meant to further understanding, or to mystify and dazzle? I really wonder sometimes.

And does a superior razor blade steel make a superior competition cutter?

Feel free to correct me if you think I'm all wet. And I really do not think this discussion will move forward until we can arrange a cutting contest between Jerry & Cliff. I'd love to see Hossom's fine grained high fine carbides go up against cliff's low carbide fine grained steel (and I will certainly attest to how well my Raker 52100 bolo chops through brush). And let the winner take on an FFD2 competition cutter!

 

[Elen]

Fiskars as a brand doesn't I don't think But they own gerber so maybe in a sort of making by association type thing.

Fiskars does make some knives, like cheapo Mora-type construction workers' knives and those small craft knives for cutting paper and stuff. (And did way before they ever bought Gerber).

 

[hardheart]

My point is, could not references to grain size, carbide size & percentage, and push cutting edge retention be better understood by more readers everywhere, than the obscure term of edge stability? Is the use of all these redundant or obscure terms meant to

I think that about covers it, haven't read anything by Landes which would seem to say more. If that is the case, I don't see how referencing grain size, carbide size, percentage is better, though. Who knows wood grain is not the same, that steel doesn't have molecules, or what a carbide is? From a lot of posts in these arguments, people seem pissed that Cliff uses a relatively new term, but I find it more descriptive. If you believe Landes' work & that finer grain, fine carbide steels are better for low angles and high polish, because that edge is more stable, then wouldn't it be easier for more readers to understand what 'edge stability references' rather than' grain' and 'carbide'? Do the readers remember any high school physics, are they engineers, do they have several hundred or more dollars worth of sharpening equipment, buy knives based on steel and not looks, read any texts about steel or heat treatment, etc?

To me, 'edge stability' is no worse than 'push cutting ability.' There was a thread asking what the heck push cutting was, and we got different answers.

 

[Jerry Hossom]

Whatever you decide to take away from this discussion, Roman Landes notwithstanding, please apply the test of reason to your decision making. Ask, "do I really believe 440A and 420HC steels will outperform CPM-154 and S30V?" In other words, "will my $5 import outperform your $100 high end version?"

You really need to think about this, because if the answer to the above questions is "yes", then you can save yourself a WHOLE lot of money and we can probably eliminate the need for this forum.

What's propping up this whole idea is that the ideal knife has an included edge angle of <20 degrees and a perfect 1 micron edge and edge durability (not edge stability) is defined as what size cabides are best supported by that geometry.

I've already admitted I haven't read Landes' book, and probably won't until it comes out in English as the definitive treatise on steel edges. From what I have read as extracts here in the forums however suggests there is a fundamental presumption that knives are intended to act like razor blades, experiencing the same demands and cutting in the same manner.

Half the argument in this thread is the assertion that this isn't so. Knife edges encounter very different and highly varied forces, especially those used for chopping things, and most of us don't use our knives for push cutting or shaving whiskers. In fact, when we pick up an average knife our next act is usally a slicing motion. If we're in the woods and are using a large knife, we may well be chopping something, maybe even something hard, harder even than chicken bones which we would never cut with our $200 European chefs knife because we already know it will roll the edge. The edge being what steel? A drop-forgeable stainless, like 12C27M perhaps? Perhaps. Truth is I don't know what steel my Henckels is made of but it certainly acts like a fairly soft, low carbide stainless. I straighten the edge with a sharpening steel everytime I use it and I resharpen the edge entirely about once a month. I use it to cut chicken bones and it rolls everytime. If I used it to chop hickory, it would roll everytime. It doesn't hold an edge worth a damn, BUT I guess it has wonderful "edge stability". .

It's interesting that the Japanese have gone in an different direction and actually apply those Japanese water stones to high carbon steels. Their best stainless knives use high carbide steels, e.g. VG-10.

Interestingly too, the Swedish knife company Fallkniven has their knives produced in Japan of VG-10, rather than a steel that might be more equivalent to 12C27M such as AUS4 or AUS6. Sweden is where 12C27M is produced of course. It's also interesting that Fallkniven takes particular pride in their knives' durability since they are intended for woods tasks like chopping.

So what does "edge stability" really mean and does it directly relate to a knife I am likely to use or is it an interesting academic exercise that defines conditions I'm not likely to encounter or care about. Is Landes really saying that his knife in 12C27M will outperform my knife in S30V over the course of the next year, given a wide range of tasks that include push cutting, slicing and chopping?

Don't counter that by saying, "well yes, if the edges are the same geometry 12C27M will outlast S30V in push cutting.... something." The edges won't be the same. You can put your 10 degree, 1 micron edge on your 12C27M blade, but my S30V blade will have a convex edge that approximates 15-20 degrees per side and I'm not really too concerned if it's 1 micron or 3 microns. It will shave hair and still be shaving hair after some very heavy duty, and even when it stops shaving hair it will STILL outcut most other knives in any task you want to throw at it because the edge is still an edge and not a rolled up piece of paper.

That ability to keep cutting is the hallmark of good steel. It's why D2 has always been such a great knife steel. It's been said many times that "D2 takes a terrible edge and keeps it forever." Talonite, a Cobalt alloy, loses its hair popping edge quickly but keeps on cutting and cutting for months.

Nothing I say here will change Cliff's mind. My concern, and only reason for posting in this thread apart from responding to the gratuitous remarks about my "sideshow" cutting tricks, is to ensure that the facts and reality of knife steels and knife edges aren't lost in the new religion of "edge stability".

If someone wants to test "edge stability" they should create a knife in 12C27M steel and use it in a head to head, refereed competition like the PCC that includes a range of tasks demanding both sharpness and durability. Witnesses may not include immediate family. Anything else is theory or an interesting laboratory experiment, nothing more.

Cliff, I'm curious about something. Why is it that when I or another knifemaker makes a claim, it isn't valid because we are selling something, our knives? On the other hand you constantly quote Landes and promote his work, even though he is also a knifemaker who sells knives and an author who is on here hawking his book with almost every post he makes. Would it help if I wrote with a German accent?

Roman, if you're reading this I want you to know I have complete respect for your work. I simply disagree with some of the conclusions as they apply to the practical application of knife edges. Admittedly, my understanding of your conclusions is somewhat influenced by Cliff's representations of them, but that is really much of what I and others here have to work with. My understanding is also biased by my own disagreements with what are apparently accepted metallurgical principles, namely that hardness alone defines yield strength. I believe I've demonstrated otherwise in the above photo. Similarly, I disagree that your premise that "edge stability" defines edge retention in the knives we carry, particularly in view of the diverse uses to which knives and edges are applied.

Ironically, I'm an almost rapid supporter of tough steel. It's one reason I think CPM-3V is the best. But, everything in moderation. Toughness can suck; take S7 for example. And other things are important too.

 

[the possum]

While I always find discussions of this nature interesting, for some reason I get the feeling I've already read most of this stuff recently... somewhere....

So, anyway, guys. What kind of performance would you expect out of a better blade as compared to what the cheap hatchet in the first post accomplished? What performance areas can be improved upon? Do they even have to be performance related? (I don't necessarily think so.)

Cliff-

The standard edge on my wood cutting knives is 8/10:0.030"-12/14:0.015". ....What is the thickness and edge angle on the cutters? Is it significantly more acute than the profile I noted in the above?

Warren Osborne also said "At 58 rockwell [M4] will bend and will not break" and that even with a primary bevel ending at 17 thousandths of an inch at 62.5Rc would not chip out.

By the way, I think it would only be fair to point out that several competitors were disqualified at the Blade Show (as I recall) because their edges took too much damage. They seem to be pushing the geometry so much, that perhaps steel choice wouldn't have mattered much (within reason). Also, Daniel Winkler has said he makes his comp cutters with an edge far sharper than what he would ever sell to a customer for real world use. This should also tell us something.

 

[Elen]

I can't claim to be an expert on the science of how steels perform in knives, but I have lots of experience of using knives. And I can definitely say that high carbide steels like VG-10 seem to perform better in field work than 12C27M: better edge-holding, higher sharpness.

Toughness can suck; take S7 for example.

Well... maybe we should tell Scrap Yard that. They use a whole lot of S7, or "modified" S7. Personally, for tough jobs, I rather much like S7.

 

[thombrogan]

S7 is awesome for big chopping knives. I have a Justin Gingrich custom in that steel and it's pure entertainment. A lot of folks love it in their Scrap Yard Knives knives, too, but I've only held those knives as opposed to chopping wood, steel, and stone with 'em.

Jerry,

Low carbide, very low edge angle, high hardness, high polish is what it takes to make 12C27 and 12C27M shine. Without all four of those ducks in a row, it's not all it's quacked up to be. There are exceptions, of course. AEB-L/13C26 is absolutely awesome for tactical folders in the RC57-61 range. I've got some folders from Kershaw with that steel and they're just great. Of course, chopping with most folders isn't so great so maybe that's not important. In fact, chopping with very thin edge angles and RC62+ steel is probably dumb even if the steel is S5, L6, AEB-L, 52100...

Your question about the knives is very good and gets better when the reader takes the time to find the answers. The folks using low-carbide martensitic stainless steels at a high enough hardness are few and far between (Kershaw, Bark River, and Eka all come to mind - so does Victorinox for their Forschner cooking knives) and they certainly aren't $5 gas station specials, so I doubt too much money would be saved (especially because Kershaw and Bark River keep coming up with new knives).

 

[Jerry Hossom]

Thom, this thread as with the previous thread that was closed deals/dealt with chopping tasks. Even discounting my contention these steels are not strong and will roll easily even at high hardness, they are not wear resistant steels and I have some difficultly understanding why you would use them in any application that might entail cutting hard or abrasive materials or would encounter hard impacts as in chopping.

Also, I'm having some trouble heaping 52100 and L6 in the same pile with 12C27M and 420hc. I certainly wouldn't give AEB-L higher marks than S30V in any application I know of, and I own Kershaw knives in both steels so I have some sense of what they offer. S7 might be OK for a beater/chopper, but it certainly doesn't offer much wear resistance and it is suscepible to deformation. I doubt you'd want to put a very fine edge on S7 and cut something hard.

Are Forschner Cooking knives substantially better than Henckels Professional Grade knives?

I sense there is a belief that steels like S7 are new discoveries in the knife world. Nobody used them as recently as 5 years ago, and that wasn't entirely an oversight. A good number of makers tried them and didn't think they brought much to the table, not enough to stop using O1 or 1084 anyway.

Chopping with thin steel edges at high Rc's is what they do in the PCC events. That's why I keep mentioning it.

Chop a nail! If what is said about these steels is true, you can't do worse than with the lousy old 154CM blade in the pic above.

 

[thombrogan]

Thom, this thread as with the previous thread that was closed deals/dealt with chopping tasks. Even discounting my contention these steels are not strong and will roll easily even at high hardness, they are not wear resistant steels and I have some difficultly understanding why you would use them in any application that might entail cutting hard or abrasive materials or would encounter hard impacts as in chopping.

I can see why one wouldn't care to chop with those steels, but for non-chopping, a blade made with Hitachi White Paper #2A with an 8 included degrees edge (a standard edge for cooking knives with that steel and a rare treat on neck knives with the same) will outcut steels with much higher wear resistance for longer periods of time when sharpened to the same angles.

Also, I'm having some trouble heaping 52100 and L6 in the same pile with 12C27M and 420hc.

There will be a higher shock resistance in 52100 and L6 and I think 52100 can be used to form plate martensite, but when it's used to form lath martensite, they're all kissing cousins are far as average carbide volume, size, and distribution (chromium carbides being much larger than cementite, so a lower carbon/high-chromium steel can match up with a higher carbon/low-chromium steel) in that respect.

I certainly wouldn't give AEB-L higher marks than S30V in any application I know of, and I own Kershaw knives in both steels so I have some sense of what they offer.

For me, it could just be the designs then, I guess.

S7 might be OK for a beater/chopper, but it certainly doesn't offer much wear resistance and it is suscepible to deformation. I doubt you'd want to put a very fine edge on S7 and cut something hard.

My favorite homemade test for impact toughness is to smack a used scratching post with an edge. The mixture of the hard plastic backing for the berber carpet and its flexibility around the pitch-covered pine make it harder on edges than the materials alone suggest. I've chipped 5160 bainite, S30V, and 52100 on that post, but S7 went through with flying colors. It also showed less blunting than 52100 when striking a galvanized steel pipe and dented less than INFI when chopping up a soft steel bedframe (though, to be fair, the S7 had a thicker edge). But, yes, the wear-resistance is much lower than steels like S30V, so when I used it to clear out some raspberry bushes, they cut back.

Are Forschner Cooking knives substantially better than Henckels Professional Grade knives?

Probably not, but from what you've said about yours, what my friend said about sharpening them for other people, and my Forschner's ability to hold a polished edge longer than expected, I'm assuming the steel is a little harder.

I sense there is a belief that steels like S7 are new discoveries in the knife world. Nobody used them as recently as 5 years ago, and that wasn't entirely an oversight. A good number of makers tried them and didn't think they brought much to the table, not enough to stop using O1 or 1084 anyway.

S7 is expensive, technically an air-hardening steel (though I think you can quench it in oil), and I doubt stupid thing anything I've done with my knife outdoes 5160 triple-tempered down RC58, so maybe not. I do remember reading that Loveless was fond of S5 for awhile.

Chopping with thin steel edges at high Rc's is what they do in the PCC events. That's why I keep mentioning it.

Chop a nail! If what is said about these steels is true, you can't do worse than with the lousy old 154CM blade in the pic above.

Sounds like a plan for an upcoming weekend! Thanks, Jerry! :thumbup: