Sterling454 wrote: ↑Tue Sep 16, 2025 11:24 pm
Mage7 wrote: ↑Tue Sep 16, 2025 1:08 am
Sterling454 wrote: ↑Mon Sep 15, 2025 9:31 pm
I'm trying to figure out why I would bother with S90V steel when MagnaMax provides similar (if not superior) edge retention, and improved toughness & corrosion resistance. Can anyone offer a well founded argument for why S90V won't be fully obsolesced? Testing data and/or empirical data are most welcome, I'd prefer to stay away from purely anecdotal/opinion based information.
Well you're kind of asking two different things.
Firstly, why would you bother with it?
Well, because it will be in less demand, so probably cheaper. Though, even the supply vs demand aspect of that will be difficult to anticipate. Since Niagara Specialty Metals is going to rebrand and produce it as NSM 90PM, there will undoubtedly be some confusion and FUD related to that. People may end up unaware that Niagara's S90V is the same, and there will likely be small amounts of CPM S90V around for a while. It will probably create a situation where some people will end up mistakenly believing NSM 90PM to be a new and improved formulation, and ify course the opposite will happen where some will suggest that the older stock is superior. That will end up skewing the demand between the two higher or lower than each other, but it's still unlikely that either will have nearly the same demand as MagnaMax. In the meantime they will both likely be far more available than MagnaMax is for a long time before it becomes ubiquitous, but even afterwards there still might be a likelihood that S90V might be more available, and if will turn into the same old dynamic where yester-year's supersteel is today's economic/value option--see S30V and D2 for examples.
Secondly is the question of why S90V won't be obsolete, or rather whether anyone can produce an argument for why it won't be obsolete.
According to the KSN Patreon, MagnaMax will have a 5, 8.5 - 9, and 9 - 9.5 score in toughness, edge retention and corrosion resistance. Only the first heat was actually CATRA tested, and it never surpassed S90V, but approached it at the highest levels of hardness. It might still surpass S90V that's not heat treated particularly hard, such as 58 HRC S90V vs 65 HRC MagnaMax, but even then would do so by a small margin in CATRA "edge retention". However with higher toughness and hardness, it will have better edge stability and probably maintain "sharpness" as related to the width of apex radius better. I wouldn't doubt that something like Cedric and Ada's tests have already shown it surpassing S90V, but I consider such testing to be anecdotal even if the logic that edge stability facilitated it is sound--just because it makes sense, doesn't mean it's actually what happ. So whether you can empirically say that it meets or surpasses S90V's edge holding is very questionable and/or circumstantial, and there's more supporting a subjective assessment that they'll be equal in edge holding. However in terms of toughness and corrosion resistance, MagnaMax is clearly superior
So, in summation... No, no one can offer an argument, with the parameters you defined, for why it won't be made obsolete, but there's still likely to be food reason to choose it for a while. Something can be obsolete, but remain a viable commodity. Conventional oil is thoroughly obsolete, but still sells alongside synthetic. VHS tapes and VCRs were still available long after DVDs replaced them as the defacto standard, and now DVDs have their place in the bargain bins after BluRay supplanted them.
A well thought out reply, very much appreciated.
You raise an interesting point about a potential bump in interest in S90V when it gets rebranded which I hadn't considered. Also, there will always be steel collectors - I consider myself one of them! The fact that my Mule Team in MagnaMax won't be the more readily available production melt makes it more of a collectors item to me. It would be super fun to have a CPM Proto-X version too, but those are incredibly exclusive.
Some of your other points about real-world applications are valid - edge geometry, secondary bevel grind angle, sharpening grits, hardness, etc all have major impact. For example, I have a plain-jane Buck 110 folder in 420HC with a hollow grind that I've reprofiled to roughly 12° per side and sharpened with an extreme mirror polish. It is bar far the sharpest blade I own and I use it to shave. No other steel I've tried could reach the same level of sharpness, including my Mule Team in AEB-L with the same profile and sharpening technique.
Yeah, it's worth pointing out too that the 2nd heat of MagnaMax--that made it into the Mule--ended up achieving better toughness for the same hardness level than the 1st heat, but the 2nd heat didn't have the chromium increase Larrin had wanted to test, but instead there was an erroneous increase in carbon. It will be interesting to see what the final formulation of MagnaMax will be, and one might be able to argue that the edge holding of the current production run of MagnaMax will be superior of what they're after is front-end edge retention more than wear resistance.
I think that there's been a lot of misconception about what CATRA tests are actually measuring. Larrin himself clarified that CATRA actually tests cutting ability, and that he decided "edge retention" should primarily refer to that because, "Sharpness correlates very strongly with edge width/radius but I don’t personally like that as a definition of sharpness because I prefer an objective test that uses actual cutting."
https://knifesteelnerds.com/2018/08/06/ ... g-ability/
I think that article hasn't gotten nearly enough attention, because from what I have seen, the characteristic of "edge retention" that Larrin has provided in his steel rankings is not the same as many users are conceiving of "edge retention". Think about how often you hear someone talking about how much cardboard they can cut up before the edge stops shaving arm hair. That's really not comparable to the way Larrin's rankings is framing edge retention, because practically every steel will continue to keep cutting cardboard
long after it stops shaving hair, even if some will stop cutting cardboard at all long before others, but many people consider "dull" to come long before cutting ability had been exhausted. Then when it comes to CATRA, some steels will wear the apex radius to a wider range in the very first cut than other steels, but still outcut the steel that held a narrower apex just by virtue of the edge geometry.
Cutting ability is the energy required for cutting. It includes a complete cut rather than simply the cut initiation. Many have experienced cutting with very thin knives that seem to cut even when dull, particularly for cutting tasks that do not require high sharpness. Creating a definition or independent test for cutting ability is somewhat more difficult. Factors such as friction of the material being cut adds complications that don’t allow a simple division by fracture toughness such as with the BSI. It includes many more variables such as depth of cut, edge geometry, shape and dimensions of the knife, etc. Also separating “cutting ability” from “sharpness” isn’t easy or even necessarily possible since the sharpness also greatly affects cutting ability. The first cut of the CATRA edge retention tester is perhaps the most standardized test available for cutting ability but that test isn’t perfect because even the first cut wears the edge which means that low wear resistance steels have lower values for the first cut than a high wear resistance steel. CATRA recommends using the first three cuts but that is even more affected by wear resistance.There has been some attempt to define and measure cutting ability in the German literature [18][19][20][21] but not much in English that I have been able to find.
I highlighted the section in bold because many people think of CATRA to be a test of wear resistance itself, but if it's actually a test of cutting ability that is itself affected by wear resistance, then how is wear resistance itself tested? CATRA seems to suggest you can measure that with the first three cuts, but Larrin seems to suggest that wear resistance is itself an outside factor not being
quantified by the test as much as it's just affecting it
Well, Larrin actually writes about the crossed-cylinder wear test in his article about the development of S90V:
So where S90V deviated from the previous vanadium-alloyed powder metallurgy stainless steels was the reduction in Cr down to 14%. Why reduce the Cr content and what did it accomplish? One important thing to know is that Crucible at that time used the “crossed-cylinder wear test” to measure the adhesive wear resistance of their steels. In this test a cylinder of the tool steel is worn against a cylinder of tungsten carbide. High vanadium steels like 10V had very high results in the crossed-cylinder wear test so Crucible metallurgists were also trying to get higher values in their stainless steels. In the S90V patent they point out that the major improvement in the design of the steel was improved adhesive wear as measured in the crossed-cylinder wear test.
It's worth noting too that in his article about the development of 10V, he claims that the crossed cylinder wear test is, "not particularly relevant," to knives, but he doesn't really explain why not. I guess one could say it's an apples to oranges comparison, but it seems to isolate the factors that would effect the results better than CATRA which is heavily influenced by edge geometry, toughness, hardness, etc. Of course the crossed cylinder test will have its own set of factors influencing things too, but it might purely reflect wear resistance whereas CATRA will also have edge stability playing a role in which steel has better wear resistance through slicing. In any case, whether CATRA actually can give a fair idea of pure wear resistance with the first three cuts or not, if Larrin did measure that, it doesn't seem like he included that in his rankings, but instead only focused on the total cards cut.
So even though on paper, S90V and MagnaMax might have very similar CATRA scores, it doesn't really indicate which one might maintain a narrower apex longer. Now, one would think that MagnaMax at higher toughness and hardness will have better edge stability and resist deformation like chipping and denting better than S90V, and so it should hold a narrower apex longer by virtue of that. On the other hand, if both have equal edge stability that preclude deformation from denting/rolling or chipping, then which apex will remain narrower will come down to wear resistance and it's hard to definitively say which will be higher in that respect. I think the only way to even make an educated guess about that one would need to know the specific carbide percentages. S90V has 13% CrVC (vanadium-enriched chromium carbide) and 9% MC (vanadium carbide) but given the final composition of MagnaMax hasn't even been published yet, I haven't seen anyone publishing carbide percentage estimates.
Anyway, I'm blabbing, but long story short I don't really think the CATRA scores give a full picture of whether it will have better edge retention unless cutting ability is the only characteristic of edge retention considered, but personally I prefer steels that hold a fine edge longer than ones that take longer to exhaust cutting ability, and it seems like S90V could possibly still win out there--or at least there's just not any empirical data definitely showing that it won't.
Edit:
Also, I noticed in your signature you have both the T15 and 15V Mules, and that's a great example of what I'm talking about. In my testing cutting through cardboard, T15 maintained a better BESS score through 100 slices through cardboard than 15V, even though 15V has better CATRA scores.
12 inch machete or Kukri 
?). Then a strop on 1 micron diamond paste and they're as sharp as glass again. Worth experiencing, it doesn't compare to those old crappy kyocera "ceramic knives" that have crumbling edges.