Just curious about Police 4, why K390 and NOT M390?

[tnguye21umbc]

Just curiosity from a newbie about the Police 4 K390... Why was K390 selected for the offering and not M390?

Considering others like PM2 which in the past had come in both

[abbazaba]

Sal has said that he made the Police4 for himself, with K390 and G10 as the initial release. It's hard to disagree with the decision after using it. M390s only advantage over K390 is corrosion resistance IME.

[TenGrainBread]

K390 is a production steel for Spyderco. It's on a lot of models in the catalog. Both versions of the K390 Police are/were regular production.

I believe M390 has only been used on a regular production Spyderco on some of the made-in-Italy Spyderco models, because the maker there uses it a lot. Outside of that, it has only been used for exclusives.

M390 is a balanced steel but is a bit ubiquitous in the market and also is relatively similar to S30V, which Spyderco already offers. K390 is a high edge retention non-stainless steel that offers a good alternative to more balanced steels like S30V. So to me wouldn't make sense to use M390 over K390 for the Police.

[aaronkb]

Just curiosity from a newbie about the Police 4 K390... Why was K390 selected for the offering and not M390?

Considering others like PM2 which in the past had come in both

Welcome to the knife game!

I remember as a newbie it was easy to fall for a lot of hype and myths. M390 is a great all-around steel (when it’s heat-treated properly - many companies cheap out on the heat treat and rely on the steel name hype to sell knives).

K390 is a BEAST and outperforms m390 in nearly every way (again, given a decent heat treat). The only exception is corrosion resistance.

[p_atrick]

I believe it was KnifeWorks that did a Delica recently in 204P. Perhaps they will do a Police in that configuration.

[MotoBro]

I believe the Police is meant to be a “hard use” knife so K390 is perfect for that. M390 and it’s American variants (204p & 20CV) are my favorite steels for EDC knives but they aren’t super tough so I wouldn’t recommend them for hard use.

I do find it a bit disappointing that most of the really tough steels usually aren’t stainless. CruWear seems to be the exception to that though. It’s pretty tough and corrosion resistant, not completely “stainless” though.

[ChrisinHove]

I think Spyderco had to buy quite a lot of K390 in the first instance.

[Donut]

There really is a limited number of Spyderco knives in M390 for whatever reason.

[Jared]

I believe it was KnifeWorks that did a Delica recently in 204P. Perhaps they will do a Police in that configuration.

Yeah, it was. I bought one of them. It’s actually a favorite of mine.

[TenGrainBread]

I believe the Police is meant to be a “hard use” knife so K390 is perfect for that. M390 and it’s American variants (204p & 20CV) are my favorite steels for EDC knives but they aren’t super tough so I wouldn’t recommend them for hard use.

Where did you get the info that K390 is tougher than M390? I have seen test numbers saying that they are pretty similar at the same hardness, and I would guess in most actually applications, M390 comes out tougher because it is generally tuned to a lower HRC than K390 (60-64 vs K390 at 64-66). Neither are very tough when it comes to "hard use" steels, and based on the blade geometry I would not call the Police a hard use folder. It's more of a slicer and designed for SD and utility use, not chopping, prying, etc

[vivi]

K390 sharpens more easily despite holding an edge longer. Doesn't rust very fast for a carbon steel either.

[StuntZombie]

K390 sharpens more easily despite holding an edge longer. Doesn't rust very fast for a carbon steel either.

I used a K390 Endela for a few days in a very salty environment, and though I had a few speckles of rust show up, I thought it did well for being a non-stainless tool steel.

[yowzer]

I believe it was KnifeWorks that did a Delica recently in 204P. Perhaps they will do a Police in that configuration.

Knifeworks had a Delica in 204P, Bento did M390, DLT did 20CV. The latter two are still available.

[MotoBro]

I believe the Police is meant to be a “hard use” knife so K390 is perfect for that. M390 and it’s American variants (204p & 20CV) are my favorite steels for EDC knives but they aren’t super tough so I wouldn’t recommend them for hard use.

Where did you get the info that K390 is tougher than M390? I have seen test numbers saying that they are pretty similar at the same hardness, and I would guess in most actually applications, M390 comes out tougher because it is generally tuned to a lower HRC than K390 (60-64 vs K390 at 64-66). Neither are very tough when it comes to "hard use" steels, and based on the blade geometry I would not call the Police a hard use folder. It's more of a slicer and designed for SD and utility use, not chopping, prying, etc

Honestly I don’t have much personal experience with K390 but all the reviews rave about it as an amazing steel except for it’s poor corrosion resistance. Someone else in this thread claimed that it outperforms M390 in everything but corrosion resistance. So maybe I got the wrong impression that it was a tougher than average steel.

I’ve also seen it compared to M4, which gives me the impression that it’s tough. Here’s a topic comparing them, calling it the “M4 killer”.

viewtopic.php?t=83660

[bearfacedkiller]

I wouldn’t call a steel with that carbide content that is run that hard tough. I also wouldn’t call a knife with a 4.5 inch blade made from 3mm stock with a full flat grind and distal taper a hard use knife.

The Poilce4 is a high performance cutter and K390 is a highly wear resistant steel run at high hardness. This knife cuts aggressively and does it for a long time.

[marty_bill_]

Tool steel vs Stainless steel = tool steel for the win every time!! K390 is the bomb!!

[ykspydiefan]

I am stuck on stainless as I am often near the ocean. I would like more M390. I do not think I will get it from Spyderco. Mostly, I would like a drop point hunter without a finger choil.

I am keen to say more M390 please. But I also recognize that Spyderco fans seem to be more focused on the next best steel, and M390 is sooooooo 2010.

[Skywalker]

I am stuck on stainless as I am often near the ocean. I would like more M390. I do not think I will get it from Spyderco. Mostly, I would like a drop point hunter without a finger choil.

I am keen to say more M390 please. But I also recognize that Spyderco fans seem to be more focused on the next best steel, and M390 is sooooooo 2010.

Spyderco has used a decent amount of M390 in regular production models when you count the same steel "recipe" made by other foundries - that is, CTS-204P and CPM-20CV.

Searching Spyderco's site real quick for just regular production models,
M390:
Pattadese
Spyopera
204P:
Southard (brown/satin and black/black variants)
20CV:
Watu
Bombshell
Zoomer
Sustain

Plus Mule Team 11 (M390) and Mule Team 23 (20CV), and a whole mess of exclusives - Military, Paramilitary 2, Para 3, Manix 2, Yojimbo 2, Delica... No Endura yet; maybe BBS could do one in blue/M390 or KW could do one in green/204P.

So don't give up hope yet... I think Spyderco will continue to use it. Going by RamZar's threads, the regular production Watu and SpyOpera released in 2020 and the Pattadese in 2021, plus all the exclusives. That suggests to me a good level of current support for the steel, and not something that Spyderco wants to leave back in 2010. :)

[MotoBro]

Yeah I’m not really sure there’s anything new that’s come along in the past 10 years that beats M390/204p/20CV as the overall best stainless steel for EDC blades. Of course there’s always a new steel with slightly better edge retention but none that are cheap enough to mass produce knives with. There’s a reason you don’t see a lot of knives in S125V & REX-121. The cost to manufacture knives from those steels is too high for production knives.

S45VN is one of those steels that’s actually cheaper to work with than S30V but offers better edge retention & corrosion resistance which is why many manufacturers are making it their new standard steel. But I don’t see it being the “M390 killer” simply because of the name. It doesn’t sound like a major upgrade from S30V or S35VN, so people are just going to assume it’s slightly better than those. But some of the tests I’ve seen do make it seem like a better M390 because it’s easier to sharpen but offers similar edge retention and corrosion resistance.

[JSNV]

I am stuck on stainless as I am often near the ocean. I would like more M390. I do not think I will get it from Spyderco. Mostly, I would like a drop point hunter without a finger choil.

I am keen to say more M390 please. But I also recognize that Spyderco fans seem to be more focused on the next best steel, and M390 is sooooooo 2010.

I have one of the limited run Manix 2’s in M390 (brown G10 satin blade). The heat treat appears to be well done and it sharpens up nicely. I still see them for sale on a number of sites and there is a dlc version as well.