K390 - Manix2 or Shaman?

[salimoneus]

Where are either of these? I mean there's a bazillion other variations of almost every model, and that's great, but it seems like this steel specifically is such a good fit for either of these models.

Those two are supposedly the more "harder use" model folders in the lineup, so does that not beg for a K390 pairing? What am I missing here...

[sovereign]

Neither are produced in Japan.

[silver & black]

Neither are produced in Japan.

Why does that matter?

[sovereign]

Neither are produced in Japan.

Why does that matter?

When is the last time you saw a Golden model in K390?

[salimoneus]

Neither are produced in Japan.

Why does that matter?

When is the last time you saw a Golden model in K390?

As far as I know, the Para2 and Para3. So no reason they can't make either or both Manix2 or Shaman, been done before can be done again.

[silver & black]

Neither are produced in Japan.

Why does that matter?

When is the last time you saw a Golden model in K390?

I have a PM 2 with K390. It's a Bento Box exclusive, but..............

[silver & black]

For what it's worth.... I'd purchase the Shaman and the Manix in K390 without thinking about it.

[Wowbagger]

Neither are produced in Japan.

Why does that matter?

When is the last time you saw a Golden model in K390?

I have a PM 2 with K390. It's a Bento Box exclusive, but..............

Yup !
I really like my PM 3 Bento Box K390 .

Between the Manix and the Shaman I would go Manix . Unless , maaaaybe if they did the Shaman K390 in the "rough" FRN .
Aaaain't gonna happen .

[DansGearAddiction]

I thought I heard in one of the SHOT Show videos with Eric that K390 was going to be replacing Maxamet (since Erasteel is discontinuing it) once the supply is exhausted. My memory could be wrong or I misheard it.

With that being said, I'd absolutely buy a Manix or Native in K390.

[Coastal]

If any model I already like becomes available in K390, it's a nearly automatic purchase. A Manix would definitely be automatic.

[M_J87]

CruWear, rex45 or 15V? I'll be honest I haven't been too impressed with K390 myself. Takes a great edge but it stains if you look at it funny.

[Midnightrider]

Those two are supposedly the more "harder use" model folders in the lineup, so does that not beg for a K390 pairing? What am I missing here...

P4, and done. The G10 is out of production but if you like FRN you're in like Flynn

[salimoneus]

CruWear, rex45 or 15V? I'll be honest I haven't been too impressed with K390 myself. Takes a great edge but it stains if you look at it funny.

It doesn't sound like you have worked with the Japanese models with K390, if so you'd very likely have a different take. The Japanese K390 easily bests both Rex45 and 15V by a fair margin.

Yea the US versions of K390 do not fair as well as what the Seki City factory is producing, but that's no excuse. Are you implying that the US can't do at least as good a job as producing a knife blade made in the same exact steel as Seki City? I sure hope not.

15V is not in the same category as K390, it's not even in the same ballpark as far as toughness.

If anything I should see people arguing against my proposition saying that 10V versions of both Shaman and Manix2 are about as good as K390, which I actually somewhat agree with. Although I still prefer K390 to 10V.

[Mage7]

CruWear, rex45 or 15V? I'll be honest I haven't been too impressed with K390 myself. Takes a great edge but it stains if you look at it funny.

It doesn't sound like you have worked with the Japanese models with K390, if so you'd very likely have a different take. The Japanese K390 easily bests both Rex45 and 15V by a fair margin.

Yea the US versions of K390 do not fair as well as what the Seki City factory is producing, but that's no excuse. Are you implying that the US can't do at least as good a job as producing a knife blade made in the same exact steel as Seki City? I sure hope not.

15V is not in the same category as K390, it's not even in the same ballpark as far as toughness.

If anything I should see people arguing against my proposition saying that 10V versions of both Shaman and Manix2 are about as good as K390, which I actually somewhat agree with. Although I still prefer K390 to 10V.

15V is about half as tough as K390 at the same hardness, but that's according to Dr. @Larrin Thomas whereas the Spyderco models have @Deadboxhero's proprietary heat treat protocol.

It seems like 15V and 10V from Spyderco are also ran a bit harder than K390 in general.

https://steelhardnesslab.com/?steel=Boh ... b=database

https://steelhardnesslab.com/?steel=Boh ... b=database
https://steelhardnesslab.com/?brand=Spy ... b=database

https://steelhardnesslab.com/?brand=Spy ... b=database


Depending on what you're using your blades for, 10V/K294 and 15V from Spyderco should have a lot more strength than K390 in addition to higher wear resistance.



10V and Rex45 are both in the middle area between toughness and edge retention



But that's CATRA data and I don't really feel like CATRA truly represents the type of edge retention most people are looking for. Since the edge apex radius is already significantly blunted after the very first cut, it's more of a measure of how long a dull edge can keep cutting rather than how long an edge stays sharp.

More about that in these articles...

https://knifesteelnerds.com/2018/06/18/ ... retention/
https://knifesteelnerds.com/2018/08/06/ ... g-ability/

When it comes to steels that actually hold a keen edge for longer, I like T15 and Rex45 more than 15V and 10V/K294 and I think it's because of the very high hardness.

https://steelhardnesslab.com/?steel=CPM ... b=database
https://steelhardnesslab.com/?steel=CPM ... b=database

I think K390 could have the potential to hold a keen edge longer if it were heat treated harder. In Dr. Thomas's book, "Knife Engineering" he shows that it could still have a charpy score of ~7.5 ft-lbs even at 66.5 HRC. That'd pretty close to T15 (8 ft-lbs at 65 HRC) and better than Rex45 (~6.5 ft-lbs at 66 HRC) but 10V/K294 is similar and I didn't find it held its keenness as well for some reason.

[M_J87]

CruWear, rex45 or 15V? I'll be honest I haven't been too impressed with K390 myself. Takes a great edge but it stains if you look at it funny.

It doesn't sound like you have worked with the Japanese models with K390, if so you'd very likely have a different take. The Japanese K390 easily bests both Rex45 and 15V by a fair margin.

Yea the US versions of K390 do not fair as well as what the Seki City factory is producing, but that's no excuse. Are you implying that the US can't do at least as good a job as producing a knife blade made in the same exact steel as Seki City? I sure hope not.

15V is not in the same category as K390, it's not even in the same ballpark as far as toughness.

If anything I should see people arguing against my proposition saying that 10V versions of both Shaman and Manix2 are about as good as K390, which I actually somewhat agree with. Although I still prefer K390 to 10V.

Any experience I've had with K390 has been Japanese. I wasn't implying anything about one factory's ability over another, I simply stated I wasn't impressed with it.

Is your worry about toughness arbitrary or has 15V failed you in use where it wouldn't have in K390?

[Wartstein]

CruWear, rex45 or 15V? I'll be honest I haven't been too impressed with K390 myself. Takes a great edge but it stains if you look at it funny.

I am certainly not one of the "steel guys" around here so take my experiences as anecdotal and with many grains of salt.

That said: In my use K390 develops an imo beautiful patina comparably easy indeed, more so than REX 45, but actually less spots/pitting for whatever reason ( both steels don't show any corrosion issues that would be more than just visual in my personal use and I don't do anything at all to prevent corrosion (like oiling the blades)).

A k390 SE blade like my Endela has in a Manix LW (preferably with a handle in the nice "Seki K390 blue")?
Instant buy!

[Larrin]

But that's CATRA data and I don't really feel like CATRA truly represents the type of edge retention most people are looking for. Since the edge apex radius is already significantly blunted after the very first cut, it's more of a measure of how long a dull edge can keep cutting rather than how long an edge stays sharp.

More about that in these articles...

https://knifesteelnerds.com/2018/06/18/ ... retention/
https://knifesteelnerds.com/2018/08/06/ ... g-ability/

That’s not what I said. I said that overall edge retention correlates with edge loss during initial cuts. That does not mean there is hidden data within the first cut that contradicts the rest of the trends.

[Mage7]

But that's CATRA data and I don't really feel like CATRA truly represents the type of edge retention most people are looking for. Since the edge apex radius is already significantly blunted after the very first cut, it's more of a measure of how long a dull edge can keep cutting rather than how long an edge stays sharp.

More about that in these articles...

https://knifesteelnerds.com/2018/06/18/ ... retention/
https://knifesteelnerds.com/2018/08/06/ ... g-ability/

That’s not what I said. I said that overall edge retention correlates with edge loss during initial cuts. That does not mean there is hidden data within the first cut that contradicts the rest of the trends.

Sorry, I should probably specify that I'm not quoting you as if we share the same conclusion. My assertion that CATRA is testing a blunted edge after the first cut is my own. However, I came to that conclusion after interpreting various things you wrote about it, perhaps incorrectly?

I'm not actually sure what you mean by there being hidden data within the first cut, or that it may contradict the rest of the trends. I guess that there's some data that would show the rest of the test to be flawed because of how much the apex radius increases during the initial cut is hidden data? I don't think it negates the rest of the CATRA data if that's the case, I just believe that cut-initiation force is more relevant to the type of 'edge retention' that people want. At least people who are obsessed with sharpening. When someone comes home and strops their blade at the end of the day to get it back to hair popping sharp, that's not really restoring cutting ability--at least not directly. From what I understand of your research it does so indirectly, but that user was primarily focused on cut initiation force, or at the very least intuitively ensuring that cutting ability remained as high as possible by ensuring cut initiation force was as low as possible, right?

In part of one of the articles you say:

You can see that the initial cut length with a smaller angle is considerably higher and that the difference holds basically to the end of the test. This finding is significant because some have speculated that lower angle edges start out sharper but a more obtuse edge lasts longer [2]. And with the high wear that occurs in the CATRA test it isn’t likely that the situation would reverse with even further cutting. The initial blunting rate is relatively rapid regardless of angle and it then begins to level out. The highest TCC measured was over 1000 mm with an angle of 20°, and this decreased all the way to under 100 mm with 56°. In a CATRA study by Bohler-Uddeholm [3] with a range of steels, but unspecified edge geometry or sharpening, 154CM was measured at 547 mm, and M390 was measured at 959 mm. The 547 mm value would be with an edge angle around 30° in this study if other parameters are similar. So if the edge angle of a 154CM knife is reduced from 30° to 20° then it can match or exceed a steel with 75% greater wear resistance.

When you reference the blunting, you mean the downward trend of cards sliced per cut right? And I am assuming you meant relative to the rest of the trends in the same test. But something must be responsible for that decrease, and in the absence of edge large scale deformation like chipping or rolling, it seems like the obvious conclusion is that it's due to the edge apex radius rapidly increasing due to abrasive wear.

So, yes I think there's hidden data in respect to how much that edge apex radius increases--or whether it does, and/or if that even really has any bearing on things at all. For all I know the radius would still be small enough to support low cut initiation forces, but it wasn't tested. I guess it's less 'hidden' and more unknown, but I'm not saying it invalidates anything.

To be perfectly precise with what I'm saying, I just feel that 'edge retention' is a bit ambiguous and can mean how well 'cutting ability' is preserved and how well 'low cut-initiation force' is preserved, and I personally am more interested and concern with the latter and I feel like most people who are enthusiastic about achieving and maintaining high levels of sharpness would be too. We're probably the minority compared to how many users are just more concerned with how well a knife keeps cutting with a reasonable level of force applied, but that's all I'm really saying. I suppose I should try to be less disparaging of CATRA, but I just so often see people using CATRA data to insist one steel should stay sharper for longer, but in reality is it actually that it stayed sharper longer or that it kept cutting longer even after its cut initiation force rose above a threshold most would consider 'sharp'.

Anyway, I think I'm making word salad, but this topic seems to have a lot of ambiguity so I wanted to be as precise as possible. I'd rather just be wrong than misunderstood :)

[TkoK83Spy]

People get too caught up in this stuff. Just use your knives and sharpen to your best ability and let your own results decide for you. This extreme level of nerdness isn't really necessary in a pocket knife! It's ok to be simple/simpfly

It seems to be thought into way too deeply sometimes instead of allowing your own experiences and personal abilities to judge for yourself. Plus, lets face it...how many people are really going to be able to tell the difference between steels that are fairly similar anyways??

[Larrin]

I don’t understand what you are saying by differentiating between cut initiation force and cutting ability, so it is hard to answer any follow up questions after that.
You also seem to be implying that an edge retention test would only be accurate if the edge was losing sharpness linearly. All of the edge retention testing I’ve ever seen does not show linear loss in sharpness, cutting ability, etc.