HRC Database

[TaylorHardness]

Hello all. I’d like to introduce myself the best that I can. My name is Taylor, or u/679696 over on Reddit. I’d like to apologize in advance, I am a bit socially awkward and am often told I sound condescending and arrogant. But I ensure you all that I am not intending to come across this way, I aimt to educate and inform the knife community to the best of my ability. I am the guy who has been posting nonstop hardness results on Reddit for everyone to see. I currently work in an accredited independent metallurgical testing laboratory. I am the lead technician in my department, and have a bit over 5 years of experience and training in Rockwell hardness testing. I started this project after a YouTube video of a knife channel popped up on my feed, and I immediately made note of how poorly the test was ran. This led to me starting my own testing on my personal knives. I currently have full access to 2 calibrated and high quality Rockwell hardness machines. A Mitutoyo HR-530, and a Newage AT130 RDS. I hold myself to a much higher standard for hardness testing due to my professional background and years of training. I have made many comments suggesting that the other tests being performed were invalid for a multitude of reasons. Namely: non calibrated machines, lack of proper verification blocks, poor indentation placement, low quality machines sourced from Ali-Express and similar bargain market websites, and a lack of training on the technician end. I am running all of my testing according to ASTM E18, with a few changes. The current industry standard is a *mimimum* of 3 readings per sample. I find that to not be enough data for a knife blade, as each side of the blade can have a difference of up to 2 HRC points based on my own personal testing. I have also taken note of many testers not removing the blade from the frame/scales. This can lead to the balance of the blade throwing the results off by a good bit. Me and Skylark disagree on which specific YouTubers are doing proper testing, but we do agree that most are doing a very, VERY poor job, with the exception of a very small handful. I intend to test as many blades from as many companies as I can, as fast as I possibly can. Thank you all for your continued support! If you have questions or feedback, you can reach me through Reddit at u/679696, or email me at TaylorHardness@gmail.com. I am currently taking in shipments for hardness testing, although I do charge $10/blade in order to cover my various costs, and contribute to further testing. Thanks again!

[Wowbagger]

Not many steels in that range can handle lower geometries like Z-Max/Rex 86 can. That's the one thing about it that makes it incredibly unique. I wish they'd do some more with this steel personally. It's a great one.

I'm sure Sal is listening .

[Skylark427]

Not many steels in that range can handle lower geometries like Z-Max/Rex 86 can. That's the one thing about it that makes it incredibly unique. I wish they'd do some more with this steel personally. It's a great one.

I'm sure Sal is listening .

I hope so, it really is an amazing steel I'd love to see more of it.

Hello all. I’d like to introduce myself the best that I can. My name is Taylor, or u/679696 over on Reddit. I’d like to apologize in advance, I am a bit socially awkward and am often told I sound condescending and arrogant. But I ensure you all that I am not intending to come across this way, I aimt to educate and inform the knife community to the best of my ability. I am the guy who has been posting nonstop hardness results on Reddit for everyone to see. I currently work in an accredited independent metallurgical testing laboratory. I am the lead technician in my department, and have a bit over 5 years of experience and training in Rockwell hardness testing. I started this project after a YouTube video of a knife channel popped up on my feed, and I immediately made note of how poorly the test was ran. This led to me starting my own testing on my personal knives. I currently have full access to 2 calibrated and high quality Rockwell hardness machines. A Mitutoyo HR-530, and a Newage AT130 RDS. I hold myself to a much higher standard for hardness testing due to my professional background and years of training. I have made many comments suggesting that the other tests being performed were invalid for a multitude of reasons. Namely: non calibrated machines, lack of proper verification blocks, poor indentation placement, low quality machines sourced from Ali-Express and similar bargain market websites, and a lack of training on the technician end. I am running all of my testing according to ASTM E18, with a few changes. The current industry standard is a *mimimum* of 3 readings per sample. I find that to not be enough data for a knife blade, as each side of the blade can have a difference of up to 2 HRC points based on my own personal testing. I have also taken note of many testers not removing the blade from the frame/scales. This can lead to the balance of the blade throwing the results off by a good bit. Me and Skylark disagree on which specific YouTubers are doing proper testing, but we do agree that most are doing a very, VERY poor job, with the exception of a very small handful. I intend to test as many blades from as many companies as I can, as fast as I possibly can. Thank you all for your continued support! If you have questions or feedback, you can reach me through Reddit at u/679696, or email me at TaylorHardness@gmail.com. I am currently taking in shipments for hardness testing, although I do charge $10/blade in order to cover my various costs, and contribute to further testing. Thanks again!

Good to have you here brother. I'm sure a lot of guys will be willing to contribute, and I'm sure everyone is eager to talk to you. I'll just add that I agree with what you said on the testing. I've glossed over it briefly here before in a previous comment. I also agree that the YouTuber in question didn't test the blade properly, I haven't seen a lot of his videos to know, but yes, having the entire handle hanging off the anvil can really mess with results.

Glad to have you here

[Synov]

Z-Max and 3V are the missing pieces in the Spyderco puzzle. Only one release for each is not enough for these amazing steels!

[Wowbagger]

I am a bit socially awkward and am often told I sound condescending and arrogant.

Well at least now I won't be the only one .

Give 'em heck with the REAL Science !

[Skylark427]

Z-Max and 3V are the missing pieces in the Spyderco puzzle. Only one release for each is not enough for these amazing steels!

I would absolutely love a 3V Mule with a modern heat treatment. 3V is an absolutely amazing steel with a heat treatment more optimal for knives. It's an absolute beast. Btw, good taste in knives

[Red Leader]

Z-Max and 3V are the missing pieces in the Spyderco puzzle. Only one release for each is not enough for these amazing steels!

I’m with you. I’ve been beating the 3V drum for a while now, and others have also longer than me. The strength is what can allow for geometries other steels may not be capable of, which can make up any wear resistance gap while still having toughness to spare. Amazing steel, and I wonder if the Erasteel version will be even better/cleaner like what we’ve been hearing with Magnacut. The potential with this steel is enormous.

[tomhosangoutdoors]

Z-Max and 3V are the missing pieces in the Spyderco puzzle. Only one release for each is not enough for these amazing steels!

I’m with you. I’ve been beating the 3V drum for a while now, and others have also longer than me. The strength is what can allow for geometries other steels may not be capable of, which can make up any wear resistance gap while still having toughness to spare. Amazing steel, and I wonder if the Erasteel version will be even better/cleaner like what we’ve been hearing with Magnacut. The potential with this steel is enormous.

I just had someone send me a 3V fixed blade at 63-34 to test. Excited to try it considering that many manufacturers run it considerably softer. I'm curious to see how it stacks up to 4V with both being 100% vanadium monocarbide with differing amounts. I would imagine it compares well and out cuts S30V, lower hardness Magnacut, and some other popular alloys.

[Skylark427]

Z-Max and 3V are the missing pieces in the Spyderco puzzle. Only one release for each is not enough for these amazing steels!

I’m with you. I’ve been beating the 3V drum for a while now, and others have also longer than me. The strength is what can allow for geometries other steels may not be capable of, which can make up any wear resistance gap while still having toughness to spare. Amazing steel, and I wonder if the Erasteel version will be even better/cleaner like what we’ve been hearing with Magnacut. The potential with this steel is enormous.

I just had someone send me a 3V fixed blade at 63-34 to test. Excited to try it considering that many manufacturers run it considerably softer. I'm curious to see how it stacks up to 4V with both being 100% vanadium monocarbide with differing amounts. I would imagine it compares well and out cuts S30V, lower hardness Magnacut, and some other popular alloys.

3V is amazing in the 63-65Rc range. You typically don't see it around 64Rc in production knives because it's very close to where the steel maxes at in customs (around 65Rc under ideal conditions, rapid plate quenching, forced air on the plate quench, into cryo within minutes of hitting room temperature) factory large batch heat treatments are limited by cooling speeds(on alloys that rely on extremely rapid cooling speeds and cryo, high speed steels gain hardness via precipitation hardening, a different heat treatment process), they are slower than plate quenching one knife at a time. So seeing max hardness, or close to it, is very difficult for production knives heat treating a batch of even as small as 5-15 blades or more at once(but typically the batches are much larger).

In my wife and mines old testing on knives all made to the same geometry(4° primary bevel, 0.125" spine, 0.007"-0.010" behind the edge) on 3/4" Kevlar and HDPE rope for the regular 26° inclusive testing, 3V scored just under 4V (3V at right around 65Rc, 4V at right around 66Rc). Both were slightly below S30V at 65Rc(which was under CPM-M4 at 65-66Rc), but 4V and S30V outperformed M390 on the same geometry at 64Rc~. 3V placed slightly under it. However, 3V, like 4V and 10V (10V at roughly 67.5Rc, but this is for pure cutting keep in mind) was stable on 1/2" Kevlar and HDPE rope all the way down to 6° inclusive 0.010" behind the edge on the 1/2" Kevlar and HDPE rope testing(lowest my old homemade system could go) whereas M390 lost stability at the second standard 20° inclusive 0.010"~ behind the edge testing on 3/4" Kevlar/HDPE rope(expected, it's microstructure is very coarse).

This is slightly different than cardboard/corrugated board testing, as Kevlar and HDPE rope is a lot more abrasive than even the most abrasive corrugated board, but I'd think the results would be relatively similar if enough runs were done to eliminate scatter and average the results between the two. I'll hopefully be starting my testing again soon, I still owe Larrin some heat treated samples of 3V at higher hardness levels for his ISO 148-1 sub size charpy impact testing, so I'll need to buy 3V anyway and get it machined to similar dimensions as a Mule for my future testing again anyway. I've just had a lot going on in my life that keeps pushing things back.

Be sure to keep me updated on the results! Always interested in other knife steel testers

[Skylark427]

Z-Max and 3V are the missing pieces in the Spyderco puzzle. Only one release for each is not enough for these amazing steels!

I’m with you. I’ve been beating the 3V drum for a while now, and others have also longer than me. The strength is what can allow for geometries other steels may not be capable of, which can make up any wear resistance gap while still having toughness to spare. Amazing steel, and I wonder if the Erasteel version will be even better/cleaner like what we’ve been hearing with Magnacut. The potential with this steel is enormous.

Yeah, Z-Max was the only high speed steel my wife and I tested that was above the 10V/A11, K390, S125V, Vanadis 8 range (they were all in the same "wear resistance category") that could handle geometries lower than 20° inclusive like those other steels(3/4" Kevlar and HDPE rope testing, knives made all to the same geometry).

3V is an amazing steel. I will say (this is for pure cutting, keep in mind) 10V and Vanadis 8 were also stable down to 6° inclusive 0.010" behind the edge (lowest my old homemade system could go) when at 67.5Rc~. All the vanadium monocarbide volume only steels seemed to stay stable at these geometries, for instance K390 stopped being stable around 10-12° inclusive, same thickness behind the edge, but this is important, the strength needed was significantly higher as the carbide volume increased. 10V needed to be at over 67Rc to remain stable that low, 3V and 4V were stable that low at 65Rc. We didn't finish testing with 15V at 68Rc to see how low it could go remaining stable, the burglary happened when we were testing it at 15° inclusive, same thickness behind the edge.

3V though was outstanding in what it could do. I really can't wait to get some barstock from Niagara and machine it and get it heat treated to max hardness to add to my own cutting tests again. Will be a bit, but 3V was amazing for what it was. It's another steel I hope Spyderco picks up again eventually.

[Mage7]

Was the K390 you tested against the 67 HRC 15V more around 65 HRC?

In my tests I was curious about why T15 seemed to degrade in apex sharpness so much more slowly than 10V or K294 and the only thing I could really think of was either the test was just not controlled enough in general, or that the fact it was harder than the other two. But there seemed to be a lot of contradicting factors in my tests that made me suspect I wasn't getting accurate results from the BESS tester. For example the 10V blade was a Kizer sheep dog, which from the hardness testing so far seems like it was very unlikely to be as hard as the K294, but yet it scored very similarly, and at much more acute edge angle to boot. It could have been the cardboard, even though I tried to use only boxes from Chewy assuming they probably sourced large amounts of it from one manufacturing batch--but even that's kind of a big assumption. So yeah I haven't bothered resuming the testing until I can find a way to tighten the controlling factors up more.

I wish there was more interest in testing which steels stayed sharper than others within a narrower threshold. I've often considered CATRA to simply be testing how long a dull edge can still cut. Even rope tests tend to beore concerned with a functional level of sharpness like paper cutting, but in my opinion most enthusiasts would touch their edges up long before they reached those levels of dullness.

My hunch has been that edge stability plays a role in maintaining the narrow width of an edge apex radius more than abrasive resistance from carbide volume can, at least to a threshold of shaving sharpness. Todd Simpson did some SEM testing showing that an apex radius should be below 100nm (.01 micron) to be able to shave whereas most carbides are well over that size to begin with, so it stands to reason that even if the steel matrix has been abraded down and still constrained to a certain width by the carbides that is narrow enough to cut paper, that it will still be well over 100nm and so the limiting factor still ends up being how well the surrounding ferrous steel matrix can resist the apex radius deforming and increasing up to or above .01 micron and I think edge stability probably plays a larger role in that than abrasive-wear resistance.

For example I would expect 52100 hardened to 66 HRC at 30 degrees inclusive to remain shaving sharp longer than 15V hardened to 64 HRC and sharpened to 30 degrees inclusive, by virtue of the 52100's steel matrix remaining narrower for longer than the softer 15V's, even if at a certain point when both dulled to the point the edge apex radius was greater than or equal to 1-2 microns that the carbides in the 15V would prevent further deformation from a abrasive wear whereas the simple iron carbides in the 52100 would wear faster, but both would be long past too dull to shave. On the other hand, if the 52100 was sharpened to 40 degrees inclusive and the 15V to 20 degrees inclusive, then the edge apex radius on the 52100 might already be closer to the .01 micron threshold just by virtue of the more obtuse geometry and if the 15V could resist chipping at that angle it would stay less than or equal to .01 micron longer thanks to the narrower geometry at the apex. Though the "if" there is a pretty big one since 15V would probably micro-chip at that acute of a geometry, and so the opposite situation where 52100 was at 64 HRC and 20 degrees inclusive remaining shaving sharp longer than 15V at 66 HRC and 40 degrees inclusive might be more likely

Without testing that's all just speculation, but anecdotally I have noticed T15 and Rex45 holding a shaving sharp edge longer than K294 and 15V, but who knows if that's just observational bias due tou hypothesis that edge stability controls for shaving-edhe retention.

The thing is, when you shape the actual carbides themselves they can still fit within that range. Yes, they can technically fracture, which is where the strength of the steel matrix really comes into play to help support said carbides. I have definitely shaved with my 15V Manix, and it cuts free hanging hairs even. Now, if you're talking razor blades with a thickness of 0.10mm and a cutting bevel of 30° inclusive (that's 0.00393701" behind the edge of a 30° inclusive angle, something I can't match nor can any custom knife maker), that's a different story. Straight razors are also a bit different, they're typically made in easy to sharpen steels that have little to no carbide both because the community that sharpens them loves the sharpening, but also because there's not much need for wear resistance in straight razors.

The K390 I(we) tested was between at 67Rc and 68Rc, I had several of each type.

I had assumed the same thing as you, thinking that the high carbide volume steels wouldn't maintain a stable edge quite as long, but the reality of it is I tested AEB-L at around 65Rc against the 10V at 67Rc and the 10V outperformed it with each test on the 6° inclusive mark. As 3V outperformed AEB-L as well.

To clarify, the steels I'm talking about that held this very thin geometry Todd showed having carbides less than 2 microns in size at 65.5Rc~ in his 15V article, and were very well dispersed. Now, as you go higher in hardness a bit more dissolves into solution (this only goes so far, vanadium is a strong carbide former) so you'd expect they would get slightly smaller still at max hardness, at least from what I've learned. I think K390's biggest limiting factor is the tungsten, it tends to remain larger, which is why in Larrin's testing it had lower impact resistance at higher hardness levels than 10V did, where 10V remained somewhat linear.

Cliff Stamp said several times on the archives that regardless of the edge bevel angle the very tip of the apex itself doesn't change in size a huge amount(he estimated 0.2 microns in size). Now, he primarily sharpened with diamond plates or conventional abrasives which we now know that will burnish carbides and/or not refine the apex very much. But when I'm getting 15V at sharpness levels similar to double edged safety razors on the BESS at far greater geometry, I'm inclined to agree with this statement. Shawn scored an 18 BESS with 15V. Now, the micro chipping is definitely an argument I can see happening, but the steels I tested showed a clear trend on what ones handled that low geometry and remained stable at maximum hardness level of the steels. That Manix I included pictures of lasted a year nearly at 28° inclusive on 3 wall corrugated board bolted to shipping pallets that contained metal parts and was still sharp when I thinned it and dropped the angle more, just with stropping once every 2 weeks or so.

And yes, at 64Rc it might be possible that 15V would wear much faster at a more narrow apex, as when I did test steels at lower hardness, the factor of which they blunted at low angles was incredibly high, like a difference of 64Rc to 67Rc would make the edge on any steel loose stability by a factor of nearly 2:1 for the same steel(I will be doing the testing on 15V at 66.4Rc and potentially using a bit of my own supply I have left to get a custom made in the same geometry at 68Rc+ again). Hardness of the steel played a massive role in the stability of the apex for just pure cutting.

Edit: also keep in mind only one sample of the K294 Mule was tested, it wouldn't be unheard of for the hardness to range 63-65Rc, as with the Kizer 10V Sheepdog it wouldn't be unheard of the range was higher than the one tested. And again, cardboard is really, really inconsistent on how much it dulls edges, it's literally a 10:1 difference between manufacturers. Cliff Stamp had to random sample and do a minimum of 10 runs with cardboard to even get "somewhat" of an idea on the edge behavior due to the nature of the inconsistencies in cardboard/corrugated board sampling, we don't know if Chewy uses the same company for all its cardboard/corrugated board.

Edit 2: Part of the reason I'm going to continue this testing is to see if these factors from previous testing still hold true, to continue what me and my wife started, and to see if somehow the testing was flawed, I'm going to up the minimum to 5 tests each, but this may still not be enough. I think you technically need a base minimum of 10 for scientific testing but I physically don't have the time or funds to do that amount. I also wish more people were interested in which steels held lower geometries better that are more optimal for knives in general.

Yeah I figured that even from one source like Chewy, it wasn't likely they were sourcing the cardboard for consistency or anything, and not to mention the hardness results I had crowd-sourced for 10V were all over the board, so it's hard to draw conclusions from that. Plus the BESS tester I had was so inconsistent. Most of the observations I had of which steels seemed to hold a shaving edge longer ended up pretty anecdotal because of all that.

It's interesting to hear how much even a few Rc points alters stability. Though also not entirely surprising since that kind of tracks work my anecdotal observations so far. Steels like Rex45 and T15 seem to hold a shaving edge longer than 10V/K294 or 15V for me, and maybe it's just by coincidence and too anecdotal to draw solid conclusions, but they also tend to be a bit harder too.

Also, in regards to the carbide size, I was thinking about it more in terms of during and after wear than after initial sharpening. I don't have any doubt the carbides can be cut to sub micron sizes necessary for shaving, but I have thought about it more in terms of how large the ones that get exposed as the steel matrix of the apex wears away are. I think about it kind of similarly to concrete... Have you ever seen the curb of a sidewalk when it's freshly poured and smoothed versus when it's been eroded for a while? After erosion the aggregate gets explodes and leaves a much bumpier and rough surface, and even though it may still have a rough 90 degree form, the very edge of it ends up pretty radiused right? Say that corner is usually always a radius, but when it's fresh and smooth it can get down to 1/4" or less. After erosion, it can never be any crisper than the average diameter of the aggregate particles, which are usually more on the order of a half an inch to am inch. I think a similar thing happens when the steel matrix "errodes" around the carbides of a steel alloy.

It's entirely probable what you're saying about carbide size holds true once the initial edge wears down. The question would then be, why is it that steels with still relatively large carbides (in comparison to the higher wear resistant high speed steels, all besides Rex 86/Z-Max in that wear resistance class, and even some a bit below it, wouldn't handle overly thin geometry, T15 was slightly above Rex 76 in my testing, Maxamet and S110V slightly above it, and Rex 86 a bit above 10V/A11/K390/Vanadis 8/S125V which were all in the same "area") tend to still outperform the lower alloy steels on cut testing, even with very thin thickness behind the edge for steels like 10V and S125V in Ankerson's testing? Or do you really need to go very low in geometry, and stick to less abrasive materials than cardboard/corrugated board, manila rope, and sisal rope to see the benefits of lower carbide volume steels with smaller carbides?

Hardness did play a significant role, it wasn't enough to put T15 at 67Rc ahead of 15V at 66Rc, at least what I'm noticing currently, but that could be scatter as controlled testing has yet to start, and the lowest hardness, and only, 15V blade I had in the old collection was just over 68Rc.

So the question is, does wear happen at these hardness ranges (66-69Rc) enough to cause the edge itself to become larger than the carbides, or is the knife sufficiently dull before that edge radius can be reached? I could add a digital microscope to the new testing, just to somewhat look and envision what is actually happening as the apex wears once it gets above the amount of force reached and a BESS score that correlates to, as I need to redefine the starting and finished parameters of the testing now that it's a different blade platform that the testing will be performed on.

All of these are questions are why I'm going to attempt to continue this testing. Increasing the minimum tests to 5 per run might help a bit more in eliminating scatter, but typically synthetic ropes are more consistent than natural, I still don't expect scatter to be zero though. I'm honestly wondering the exact same things, and the only real way for me to know the answers definitively is to do the testing again. Which is going to be a substantial effort on its own, but I really do want to know the answers. It's just likely going to take more time this time around... as it's only me doing it. But it's something I'm incredibly interested in as well, so I'm going to attempt it again, and share results as they come.

If there's anything you can think of that I could add to the testing to help it be more consistent, or better in any way, I'm open to all suggestions.

I think the prima issue that I've seen with cut testing in the commons iterations I've seen so far is that the testing and/or evaluation don't isolate the apex from the rest of the edge bevel. For example:

Edge A: 6 degree per side bevels, apex-radius of 100 nm
Edge B: 12 degrees per side bevels, apex-radius of 25 nm

Edge A is as till going to cut through most materials like rope, cardboard, CATRA card stock, etc. better than Edge B. However if you wanted to say, whittle a hair (ignoring why that would be a practical need) then Edge B would do that better than Edge A. The primary difference is that the former evaluation is engaging the edge bevels from apex to the bevel shoulder and beyond, whereas the former is only engaging the edge from the apex up to a few microns needed to penetrate the sheath of the hair before it starts whittling. While whittling hair works as a good assessment it's not really a practical task that's needed--unless you're sharpening razors.

However there's a lot of other practical cutting tasks where maintaining a low cut-initiation force is most optimal, whereas assessing how much force it takes to wedge the whole bevel through a material is a bit of a separate animal. I suppose I would suggest that one would test how well cutting cardboard or some type of material could be performed versus how well whittling or carving where a high level of finesse is needed.

One issue I see though is that even if you can find a way to isolate the evaluation of the apex only to a few microns up the bevel versus evaluating the apex and the geometry of the bevel, the actual testing itself will usually always engage both and so to really properly evaluate the apex in strict isolation one might also need to test it in strict isolation. In other words if someone is concerned with how well a knife stays sharp for whittling, then they'd probably want to whittling to be the function of dulling. On the other hand sometimes a lot of people are actually commonly interested in how low cut initiation force can remain after a long day cutting cardboard at the warehouse.

Anyway all that culminates to say that I think a microscopic examination of the apex radius and BESS tests are probably adequate to evaluate the affect at the apex, and ultimately the factor itself being tested is how low the cut-initiation force can remain. Since that's highly correlated to edge apex radius, and BESS tests it directly, I believe those measures as re adequate and the main thing prioritize is just to avoid conflating cutting-ability tests like how much force it takes to cut through a medium work how much force it takes to start cutting the medium and the latter seems more important for cutting tasks where more finesse is needed.

3V is an amazing steel. I will say (this is for pure cutting, keep in mind) 10V and Vanadis 8 were also stable down to 6° inclusive 0.010" behind the edge (lowest my old homemade system could go) when at 67.5Rc~. All the vanadium monocarbide volume only steels seemed to stay stable at these geometries, for instance K390 stopped being stable around 10-12° inclusive, same thickness behind the edge, but this is important, the strength needed was significantly higher as the carbide volume increased. 10V needed to be at over 67Rc to remain stable that low, 3V and 4V were stable that low at 65Rc. We didn't finish testing with 15V at 68Rc to see how low it could go remaining stable, the burglary happened when we were testing it at 15° inclusive, same thickness behind the edge.

A 6 degree inclusive secondary bevel on a 4 degree inclusive primary bevel? Holy cow.

From what I could measure for the Spyderco Mules and their Manix knives, the primary bevels are closer to 2.3 degrees per side, so 6 degrees inclusive would be pretty much 1 degree!? Talk about precision grinding lol

[Skylark427]

The thing is, when you shape the actual carbides themselves they can still fit within that range. Yes, they can technically fracture, which is where the strength of the steel matrix really comes into play to help support said carbides. I have definitely shaved with my 15V Manix, and it cuts free hanging hairs even. Now, if you're talking razor blades with a thickness of 0.10mm and a cutting bevel of 30° inclusive (that's 0.00393701" behind the edge of a 30° inclusive angle, something I can't match nor can any custom knife maker), that's a different story. Straight razors are also a bit different, they're typically made in easy to sharpen steels that have little to no carbide both because the community that sharpens them loves the sharpening, but also because there's not much need for wear resistance in straight razors.

The K390 I(we) tested was between at 67Rc and 68Rc, I had several of each type.

I had assumed the same thing as you, thinking that the high carbide volume steels wouldn't maintain a stable edge quite as long, but the reality of it is I tested AEB-L at around 65Rc against the 10V at 67Rc and the 10V outperformed it with each test on the 6° inclusive mark. As 3V outperformed AEB-L as well.

To clarify, the steels I'm talking about that held this very thin geometry Todd showed having carbides less than 2 microns in size at 65.5Rc~ in his 15V article, and were very well dispersed. Now, as you go higher in hardness a bit more dissolves into solution (this only goes so far, vanadium is a strong carbide former) so you'd expect they would get slightly smaller still at max hardness, at least from what I've learned. I think K390's biggest limiting factor is the tungsten, it tends to remain larger, which is why in Larrin's testing it had lower impact resistance at higher hardness levels than 10V did, where 10V remained somewhat linear.

Cliff Stamp said several times on the archives that regardless of the edge bevel angle the very tip of the apex itself doesn't change in size a huge amount(he estimated 0.2 microns in size). Now, he primarily sharpened with diamond plates or conventional abrasives which we now know that will burnish carbides and/or not refine the apex very much. But when I'm getting 15V at sharpness levels similar to double edged safety razors on the BESS at far greater geometry, I'm inclined to agree with this statement. Shawn scored an 18 BESS with 15V. Now, the micro chipping is definitely an argument I can see happening, but the steels I tested showed a clear trend on what ones handled that low geometry and remained stable at maximum hardness level of the steels. That Manix I included pictures of lasted a year nearly at 28° inclusive on 3 wall corrugated board bolted to shipping pallets that contained metal parts and was still sharp when I thinned it and dropped the angle more, just with stropping once every 2 weeks or so.

And yes, at 64Rc it might be possible that 15V would wear much faster at a more narrow apex, as when I did test steels at lower hardness, the factor of which they blunted at low angles was incredibly high, like a difference of 64Rc to 67Rc would make the edge on any steel loose stability by a factor of nearly 2:1 for the same steel(I will be doing the testing on 15V at 66.4Rc and potentially using a bit of my own supply I have left to get a custom made in the same geometry at 68Rc+ again). Hardness of the steel played a massive role in the stability of the apex for just pure cutting.

Edit: also keep in mind only one sample of the K294 Mule was tested, it wouldn't be unheard of for the hardness to range 63-65Rc, as with the Kizer 10V Sheepdog it wouldn't be unheard of the range was higher than the one tested. And again, cardboard is really, really inconsistent on how much it dulls edges, it's literally a 10:1 difference between manufacturers. Cliff Stamp had to random sample and do a minimum of 10 runs with cardboard to even get "somewhat" of an idea on the edge behavior due to the nature of the inconsistencies in cardboard/corrugated board sampling, we don't know if Chewy uses the same company for all its cardboard/corrugated board.

Edit 2: Part of the reason I'm going to continue this testing is to see if these factors from previous testing still hold true, to continue what me and my wife started, and to see if somehow the testing was flawed, I'm going to up the minimum to 5 tests each, but this may still not be enough. I think you technically need a base minimum of 10 for scientific testing but I physically don't have the time or funds to do that amount. I also wish more people were interested in which steels held lower geometries better that are more optimal for knives in general.

Yeah I figured that even from one source like Chewy, it wasn't likely they were sourcing the cardboard for consistency or anything, and not to mention the hardness results I had crowd-sourced for 10V were all over the board, so it's hard to draw conclusions from that. Plus the BESS tester I had was so inconsistent. Most of the observations I had of which steels seemed to hold a shaving edge longer ended up pretty anecdotal because of all that.

It's interesting to hear how much even a few Rc points alters stability. Though also not entirely surprising since that kind of tracks work my anecdotal observations so far. Steels like Rex45 and T15 seem to hold a shaving edge longer than 10V/K294 or 15V for me, and maybe it's just by coincidence and too anecdotal to draw solid conclusions, but they also tend to be a bit harder too.

Also, in regards to the carbide size, I was thinking about it more in terms of during and after wear than after initial sharpening. I don't have any doubt the carbides can be cut to sub micron sizes necessary for shaving, but I have thought about it more in terms of how large the ones that get exposed as the steel matrix of the apex wears away are. I think about it kind of similarly to concrete... Have you ever seen the curb of a sidewalk when it's freshly poured and smoothed versus when it's been eroded for a while? After erosion the aggregate gets explodes and leaves a much bumpier and rough surface, and even though it may still have a rough 90 degree form, the very edge of it ends up pretty radiused right? Say that corner is usually always a radius, but when it's fresh and smooth it can get down to 1/4" or less. After erosion, it can never be any crisper than the average diameter of the aggregate particles, which are usually more on the order of a half an inch to am inch. I think a similar thing happens when the steel matrix "errodes" around the carbides of a steel alloy.

It's entirely probable what you're saying about carbide size holds true once the initial edge wears down. The question would then be, why is it that steels with still relatively large carbides (in comparison to the higher wear resistant high speed steels, all besides Rex 86/Z-Max in that wear resistance class, and even some a bit below it, wouldn't handle overly thin geometry, T15 was slightly above Rex 76 in my testing, Maxamet and S110V slightly above it, and Rex 86 a bit above 10V/A11/K390/Vanadis 8/S125V which were all in the same "area") tend to still outperform the lower alloy steels on cut testing, even with very thin thickness behind the edge for steels like 10V and S125V in Ankerson's testing? Or do you really need to go very low in geometry, and stick to less abrasive materials than cardboard/corrugated board, manila rope, and sisal rope to see the benefits of lower carbide volume steels with smaller carbides?

Hardness did play a significant role, it wasn't enough to put T15 at 67Rc ahead of 15V at 66Rc, at least what I'm noticing currently, but that could be scatter as controlled testing has yet to start, and the lowest hardness, and only, 15V blade I had in the old collection was just over 68Rc.

So the question is, does wear happen at these hardness ranges (66-69Rc) enough to cause the edge itself to become larger than the carbides, or is the knife sufficiently dull before that edge radius can be reached? I could add a digital microscope to the new testing, just to somewhat look and envision what is actually happening as the apex wears once it gets above the amount of force reached and a BESS score that correlates to, as I need to redefine the starting and finished parameters of the testing now that it's a different blade platform that the testing will be performed on.

All of these are questions are why I'm going to attempt to continue this testing. Increasing the minimum tests to 5 per run might help a bit more in eliminating scatter, but typically synthetic ropes are more consistent than natural, I still don't expect scatter to be zero though. I'm honestly wondering the exact same things, and the only real way for me to know the answers definitively is to do the testing again. Which is going to be a substantial effort on its own, but I really do want to know the answers. It's just likely going to take more time this time around... as it's only me doing it. But it's something I'm incredibly interested in as well, so I'm going to attempt it again, and share results as they come.

If there's anything you can think of that I could add to the testing to help it be more consistent, or better in any way, I'm open to all suggestions.

I think the prima issue that I've seen with cut testing in the commons iterations I've seen so far is that the testing and/or evaluation don't isolate the apex from the rest of the edge bevel. For example:

Edge A: 6 degree per side bevels, apex-radius of 100 nm
Edge B: 12 degrees per side bevels, apex-radius of 25 nm

Edge A is as till going to cut through most materials like rope, cardboard, CATRA card stock, etc. better than Edge B. However if you wanted to say, whittle a hair (ignoring why that would be a practical need) then Edge B would do that better than Edge A. The primary difference is that the former evaluation is engaging the edge bevels from apex to the bevel shoulder and beyond, whereas the former is only engaging the edge from the apex up to a few microns needed to penetrate the sheath of the hair before it starts whittling. While whittling hair works as a good assessment it's not really a practical task that's needed--unless you're sharpening razors.

However there's a lot of other practical cutting tasks where maintaining a low cut-initiation force is most optimal, whereas assessing how much force it takes to wedge the whole bevel through a material is a bit of a separate animal. I suppose I would suggest that one would test how well cutting cardboard or some type of material could be performed versus how well whittling or carving where a high level of finesse is needed.

One issue I see though is that even if you can find a way to isolate the evaluation of the apex only to a few microns up the bevel versus evaluating the apex and the geometry of the bevel, the actual testing itself will usually always engage both and so to really properly evaluate the apex in strict isolation one might also need to test it in strict isolation. In other words if someone is concerned with how well a knife stays sharp for whittling, then they'd probably want to whittling to be the function of dulling. On the other hand sometimes a lot of people are actually commonly interested in how low cut initiation force can remain after a long day cutting cardboard at the warehouse.

Anyway all that culminates to say that I think a microscopic examination of the apex radius and BESS tests are probably adequate to evaluate the affect at the apex, and ultimately the factor itself being tested is how low the cut-initiation force can remain. Since that's highly correlated to edge apex radius, and BESS tests it directly, I believe those measures as re adequate and the main thing prioritize is just to avoid conflating cutting-ability tests like how much force it takes to cut through a medium work how much force it takes to start cutting the medium and the latter seems more important for cutting tasks where more finesse is needed.

3V is an amazing steel. I will say (this is for pure cutting, keep in mind) 10V and Vanadis 8 were also stable down to 6° inclusive 0.010" behind the edge (lowest my old homemade system could go) when at 67.5Rc~. All the vanadium monocarbide volume only steels seemed to stay stable at these geometries, for instance K390 stopped being stable around 10-12° inclusive, same thickness behind the edge, but this is important, the strength needed was significantly higher as the carbide volume increased. 10V needed to be at over 67Rc to remain stable that low, 3V and 4V were stable that low at 65Rc. We didn't finish testing with 15V at 68Rc to see how low it could go remaining stable, the burglary happened when we were testing it at 15° inclusive, same thickness behind the edge.

A 6 degree inclusive secondary bevel on a 4 degree inclusive primary bevel? Holy cow.

From what I could measure for the Spyderco Mules and their Manix knives, the primary bevels are closer to 2.3 degrees per side, so 6 degrees inclusive would be pretty much 1 degree!? Talk about precision grinding lol

So to test the apex in isolation, almost to the extent you're suggesting, I'd almost need to figure out a completely different test method in general, and run both tests side by side. I'm not overly against doing this. It wouldn't be overly easy though. Maybe between the two of us we can figure out a way to go about it?

On the hair whittling, I do have a video of my 15V Manix G10 (thinned around 0.010" BTE) at 26° inclusive and between 37-43 BESS whittling then cutting through a free hanging hair, overall my phone doesn't have the best camera and I've got no tripod, but we did make our edges very, very refined before doing our testing. She was better than me at sharpening, so could more easily do this, but I'm still able to produce these results, just with more patience than her.

On the primary bevel angle of the Manix and Mule, you're correct in that they're slightly over 4° primary bevels, this is actually because they're slightly convex, at least the ones I've measured. My old homemade system didn't really operate like a regular system, it was made to where the knife sat above the stones, and the stones moved in almost a grid pattern underneath the blade. I had access back then to a more expensive goniometer than I currently do today (though I am trying to save up for the CATRA one), but overall the one I have currently tells the angle pretty well.

So, maybe if we can figure out a way to test the apex in isolation as your suggesting, and still figure out a way to meaningfully measure the difference between these tests, I don't know how well BESS will pick up on lower cut forces used like that, but we may be able to think of something between the two if us that's controlled enough, and run it concurrent to my other tests. I do completely understand what you mean. It'll definitely be a project though to figure out a way to go about it. But I'm interested in if there's meaningful differences between the results.

[Red Leader]

What a cool discussion, if @sal hasn't seen it yet, it would be fun for him to jump in.

I'll have to look into Z-max and just see what is available (or was available), if I can find anything at all. Is this Zapp? Is their stuff still source-able? Would we run into the same problem w/ Z-max on a production level that we've heard about from some on here regarding the difficulties w/ manufacturing Rex-121? I'd hate to suggest that Spyderco enter into that sort of fray with Z-max on a more general production basis, but if it a bit easier to work with, maybe we could see something yet again come to fruition, pending the availability, of course. And, sales would need to be there. I'm betting a PM2 exclusive in this steel would interest more than a Mule.

Regarding 3V, what an incredible test you put that through @Skylark427 !

I have also thought that Vanadis 8 stood out - really, when you look, even at Larrin's charts, it's not hard to see things like Z-max, Vanadis 8, and 3V stand way out above many of the others.

I will continue to beat on the 3V drum until things start moving, and then probably beat on it even more loudly haha. Could you imagine a Chaparral XL or XL SE in such a steel? 2mm thick 3V in a 3.5" format? Sounds really cool. Maybe some strategic convos w/ Niagara about their version of 3V could be great, like getting some new samples to test, and possibly a future Mule, though I'd be okay with it jumping straight into a folder. CPM 3V was already excellent, but I'm curious to see Niagara's version, not to mention just how fast that steel could go if driven to 63+ HRC w/ thin stock.

[Skylark427]

What a cool discussion, if @sal hasn't seen it yet, it would be fun for him to jump in.

I'll have to look into Z-max and just see what is available (or was available), if I can find anything at all. Is this Zapp? Is their stuff still source-able? Would we run into the same problem w/ Z-max on a production level that we've heard about from some on here regarding the difficulties w/ manufacturing Rex-121? I'd hate to suggest that Spyderco enter into that sort of fray with Z-max on a more general production basis, but if it a bit easier to work with, maybe we could see something yet again come to fruition, pending the availability, of course. And, sales would need to be there. I'm betting a PM2 exclusive in this steel would interest more than a Mule.

Regarding 3V, what an incredible test you put that through @Skylark427 !

I have also thought that Vanadis 8 stood out - really, when you look, even at Larrin's charts, it's not hard to see things like Z-max, Vanadis 8, and 3V stand way out above many of the others.

I will continue to beat on the 3V drum until things start moving, and then probably beat on it even more loudly haha. Could you imagine a Chaparral XL or XL SE in such a steel? 2mm thick 3V in a 3.5" format? Sounds really cool. Maybe some strategic convos w/ Niagara about their version of 3V could be great, like getting some new samples to test, and possibly a future Mule, though I'd be okay with it jumping straight into a folder. CPM 3V was already excellent, but I'm curious to see Niagara's version, not to mention just how fast that steel could go if driven to 63+ HRC w/ thin stock.

Z-Max is definitely still available, Zapp processes steel made from other manufacturers, so since Erasteel is still making Rex 86, Zapp will/is still producing Z-Max. It's definitely easier to work than something like Rex 121, there's no comparison there. Rex 86 is the same steel as well, so it would also be available from Erasteel, as they're still making this alloy to my knowledge. I would expect a PM2 to sell pretty well in this steel. I'd love to see a Manix in it. Overall, I greatly prefer it to Maxamet, it had higher wear resistance to Maxamet in my testing, yet held a much more stable edge and was much easier to sharpen due to the finer microstructure, hence it's ability to go to lower geometries.

Also, as a good friend of mine has brought up to me... PM60/ASP 2060(Erasteel)/Vanadis 60(Uddeholm) is also a great choice readily available from several manufacturers...

They're even producing a steel that people think is "impossible" to be made still(because of rumors only Crucible could make it, I've said for a while this is incorrect and a misunderstanding on Bob's part from Niagra, and an alloys composition as a whole determines atomization temperatures, and that numerous alloys are already being made that exceed said alloys atomization temperatures as each has its own, and I've known for a bit Zapp was working on this) in joint effort with Erasteel.... I've shared the info with Shawn Houston along with the datasheet, not sure that I'm ready to make that public yet though lol.

Yes, 10V and Vanadis 8 were my absolute favorite of that range of steels. They're definitely both special. I will say I also really love the new MagnaMax, at just over 65Rc on my user, it's a great steel on a small fixed blade. I'm very impressed with it's abilities as a stainless currently. I really think MagnaMax will be great, currently it's the closest I've seen to a stainless 10V/Vanadis 8/K390. I hope the hardness can be kept relatively high in the final version, as the Mule's perform amazing in the 64.5Rc-65.5Rc~ range we've currently tested them at, and everything I've done with mine(hacking and batoning through 2-4 inch live silver maple wood, carving aluminum barstock, pennys, and copper, it's outstanding).

3V has always been my favorite of the "tough" alloys. It consistently performed extremely well(better than CPM-Cruwear due to the vanadium monocarbide only microstructure), even on larger knives, when at higher hardness with a modern heat treatment. It really performs great even at just 5% vanadium monocarbide volume, much better than you'd expect, at least on high abrasive rope cutting. I'm very curious where it ends up in the 63-65Rc range on Larrin's testing of it, so I really do need to take him up on his offer he made me on that Q&A video of sending him heat treated ISO 148-1 sub size charpy samples to test. I told him I would several months ago now, as I said, things in life keep getting in the way and I currently would need to send the samples to a knife maker to heat treat (a few offered on Larrin's Patreon page, so I have options), as my work's heat treatment setup isn't equipped to be plate quenching knives, nor would they be happy with me heat treating knives in our multi-chamber furnace. Strict work environment and all that.

Edit to mention I'd absolutely love 3V on a thin knife. I'd love to see it on a Mule, to add to my updated testing to pick up where me and my late wife left off, but I'd also be happy to get it in a thin folder as well. 3V at 63Rc+ would be amazing. There's a lot of stock at Niagara last I checked, considering I'm going to be buying a bar of it at some point soon.

[tomhosangoutdoors]

Z-Max and 3V are the missing pieces in the Spyderco puzzle. Only one release for each is not enough for these amazing steels!

I’m with you. I’ve been beating the 3V drum for a while now, and others have also longer than me. The strength is what can allow for geometries other steels may not be capable of, which can make up any wear resistance gap while still having toughness to spare. Amazing steel, and I wonder if the Erasteel version will be even better/cleaner like what we’ve been hearing with Magnacut. The potential with this steel is enormous.

I just had someone send me a 3V fixed blade at 63-34 to test. Excited to try it considering that many manufacturers run it considerably softer. I'm curious to see how it stacks up to 4V with both being 100% vanadium monocarbide with differing amounts. I would imagine it compares well and out cuts S30V, lower hardness Magnacut, and some other popular alloys.

3V is amazing in the 63-65Rc range. You typically don't see it around 64Rc in production knives because it's very close to where the steel maxes at in customs (around 65Rc under ideal conditions, rapid plate quenching, forced air on the plate quench, into cryo within minutes of hitting room temperature) factory large batch heat treatments are limited by cooling speeds(on alloys that rely on extremely rapid cooling speeds and cryo, high speed steels gain hardness via precipitation hardening, a different heat treatment process), they are slower than plate quenching one knife at a time. So seeing max hardness, or close to it, is very difficult for production knives heat treating a batch of even as small as 5-15 blades or more at once(but typically the batches are much larger).

In my wife and mines old testing on knives all made to the same geometry(4° primary bevel, 0.125" spine, 0.007"-0.010" behind the edge) on 3/4" Kevlar and HDPE rope for the regular 26° inclusive testing, 3V scored just under 4V (3V at right around 65Rc, 4V at right around 66Rc). Both were slightly below S30V at 65Rc(which was under CPM-M4 at 65-66Rc), but 4V and S30V outperformed M390 on the same geometry at 64Rc~. 3V placed slightly under it. However, 3V, like 4V and 10V (10V at roughly 67.5Rc, but this is for pure cutting keep in mind) was stable on 1/2" Kevlar and HDPE rope all the way down to 6° inclusive 0.010" behind the edge on the 1/2" Kevlar and HDPE rope testing(lowest my old homemade system could go) whereas M390 lost stability at the second standard 20° inclusive 0.010"~ behind the edge testing on 3/4" Kevlar/HDPE rope(expected, it's microstructure is very coarse).

This is slightly different than cardboard/corrugated board testing, as Kevlar and HDPE rope is a lot more abrasive than even the most abrasive corrugated board, but I'd think the results would be relatively similar if enough runs were done to eliminate scatter and average the results between the two. I'll hopefully be starting my testing again soon, I still owe Larrin some heat treated samples of 3V at higher hardness levels for his ISO 148-1 sub size charpy impact testing, so I'll need to buy 3V anyway and get it machined to similar dimensions as a Mule for my future testing again anyway. I've just had a lot going on in my life that keeps pushing things back.

Be sure to keep me updated on the results! Always interested in other knife steel testers

Just wrapped up testing and it fell pretty close to where I was expecting. Better than S30V and CruWear (albeit at lower hardnesses and higher total carbide volume) while being close to MagnaCut and a hair below 4V at higher hardness which makes sense. The whole video with my testing and findings is in the link I have at the bottom of the post if you wanted to check it out. 3V is some pretty cool stuff and I hope we see more of it in the future at higher hardnesses.

[sal]

Hi Taylor,

Welcome to our forum.

Glad to have you aboard. I don't have the time to study You tube or Reddit. Though that information will often show up here, especially with people complaining or seeking more knowledge.

We did a run of CPM-3V in a model. We've done Z wear in a Mule and we've got a Z 12 ultra BQ in queue for a Mule. I can bug the team for 3V. Is Erasteel making 3V now? Is it powdered?

sal

[Synov]

Hi Taylor,

Welcome to our forum.

Glad to have you aboard. I don't have the time to study You tube or Reddit. Though that information will often show up here, especially with people complaining or seeking more knowledge.

We did a run of CPM-3V in a model. We've done Z wear in a Mule and we've got a Z 12 ultra BQ in queue for a Mule. I can bug the team for 3V. Is Erasteel making 3V now? Is it powdered?

sal

Erasteel is indeed making CPM 3V. Considering the improved toughness in their version of MagnaCut, we may see a similar improvement in 3V. Super exciting news Sal.