Tag Archives: K390

STEEL K390 BÖHLER’S MICROCLEAN – UNCANNY BLADE MATERIAL.

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I have seen a video where someone is stabbing concrete with its Spyderco Police 4 to show how K390 is strong ! The blade of that famous knife is thin and this thinness is here for a purpose: Sal Glesser has decided to use the Police 4 plateforme according to his own desire but toughness and impact resistance may have weighed in on the decision. For once the Police is not especially aimed at the LEO but those ELU who use their thin knives hard !

“We make quite a few designs for the Law Enforcement market at this time, so the design for Police use is necessarily the case anymore, like it was in 1984. I designed the Police 4 to include what I would like in a knife, more than what a LEO might like. It’s still a kissing cousin, and large for most people. I widened the blade, enlarged the hole and selected a steel that I like to use. The design’s success in the marketplace is unknown at this time. But I get to have one. ” Sal Glesser.

K390 is not stainless. It’s a cold work tool steel which uses Bohler proprietary Microclean technology.  K390 has close to the same edge holding as A11 but is much tougher. Bohler’s third generation particle metallurgy contributes to the toughness of the steel.This steel will be hard to grind, finish and sharpen. Once it is sharp it will stay sharp for a long long long time. It’s CPM M4 on steroids which means K390 has more strength, durability, stability and wear resistance than M4 ! And I do love CPM M4.

Here is a video which confronts CPM M4 and K390:
https://youtu.be/TI53ziibeiQ

From Bohler’s commercial:

“K390 is quite simply the powder metallurgical cold work tool steel with the best properties for cold work applications available from BÖHLER at the moment. K390 MICROCLEAN was developed to meet the demanding wear resistance and compressive strength requirements of cutting, blanking and punching applications, for cold forming applications and for parts which are subjected to abrasive wear in plastics processing. Tool life can be increased by several hundred percent due to the outstanding wear resistance, high compressive strength and good toughness of BÖHLER K390 MICROCLEAN. These material properties enable our customers to make their production processes more efficient and consequently to reduce the price per part produced. Too hard to be machinable? Quite the opposite. The task of the tool steel manufacturer is to produce a steel which is, on the one hand, easy and economic to machine (with a hardness of around 280HB) and simple and unproblematic to heat treat, but which, on the other hand, has a very high hardness (up to 64HRc) and optimum performance in use. The secret lies in the powder metallurgy process. A very fine, homogeneous microstructure guarantees optimal machinability.

K390 owes its superior properties above all to the powder-metallurgical production process. The main advantages of BÖHLER MICROCLEAN steels over conventional steels are: • uniform carbide distribution • small carbide size • uniform chemical composition over the entire cross-section and length • virtually isotropic behaviour due to improved homogeneity and the absence of segregations.”

From Phil Wilson on the Spyderco Forums.:
“I have been using K390 from the start ever since it was introduced by Bohler and I got some small samples to try. A bit of history is that it is the European version of CPM 10V but not the exact chemistry (about 1% less V plus small addition of a few others). That is because the CPM 10V chemistry was protected by patent at the time. If you check the K390 data sheet it claims that the bit less V gives K 390 a little boost in impact toughness. It also can be heat treated at a lower temp. than 10v. So it is pretty much the same as the A11 grade but different in a few small details. It is hard to tell the difference between CPM 10v and BU K390 in the real world in my experience. I like both grades and they are the base line (along with Vanadius 10 and K294) from which I measure wear resistance. The 5 chrome is there to make them all air hardening among other things and does not contribute much to corrosion resistance. It is going to make a killer knife in the new offering and be another classic. Phil”

On my Urban, K390 has proven to be very tough. It is my main travelling folder. And it is a real wolf under sheep’skin. One of the little home test I got is by removing the metal around a bottle of wine’s cork. Most of the time, the knife edge is bent and shows some shining due to miss alignement but not with K390. The steel feels like plastic. On my three knives, the Pingo got the most stout blade and less pointy. This little knife is simply used very hard with zero damage to the edge: digging in wood, cut into staples, scrapping various paints and plastic. So far, even if the steel is not stainless, a mild patina has protected it from real rust.

So what do we got ? A tough blade which keeps its sharpness for a very long time. A forgiving edge which can be used by clumsy hands with no after thoughts.
The side effects are: the need of diamonds and ceramics to keep it razor.
Once convexed to me taste, I use white ceramic and some stropping just to get it mirror.

We definitively needs more knives in K390 !

 

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A Spirit In a Material World: Sting, The Police.

Like I have said in my previous review of that venerable folding knife :
It has taken me a very long time before to get any interest in the Police model.

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My first real step in the wide Spyderco world was the Terzuola Starmate and the Millie. The Starmate was equipped with some super new steel the CPMS60V named CPM440V then. It was the beginning of the powder steels and Spyderco was experimenting on a bold plateforme even using (like the Millie) hidden nested liners !

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The actual Police with its “non nested” liners is thinner than the Terzuola C55.

Steel wise:
Meanwhile in the 90’s, new Japanese steel VG-10 was used on their first fixed blade “the Moran” and the Seki made Police was then “stuck in GIN-1 or GIN-2″… Ah, I was and I’m still a “steel whore” (a term of self qualification of Sal Glesser) after all. I was unfaithful and really attracted by M2HSS version of the AFCK…  Not for the patina (as they were PVD covered) but for the benefits of getting a thin pointy blade with more lateral strength than usual stainless steels of that time. As much as I loved the AFCK, the long version BM800 was “plagued” by a titanium linerlock which was less solid than the short version with its stainless liners.
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I have later used (a lot) an “oval hole” BM806 with a much stronger lock and D2 tool steel blade.

K390 is a wonderful steel. Strong even not as strong as CPM3V found in the Tuff. I have used the 4th Police as an Ice pick with no fear of breakage.

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Like the famous Opinel: thin blades are such a joy to use. A super K390 gives strength to a thin ground blade and turns the “old LEO tool” into a workhorse designed for ranchers. I was disappointed the Spyderco Powerlock was not used in the new Police but, well, the Police feels so solid: I can’t complain.

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Now I would do a maximum of lobbyism to get a Nilakka Sprint Run using K390. This steel used is purely a pleasure to keep razor sharp only by stropping it on leather.

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Now for the con, I have found the grind is not really even. There is some sort of wave on both side of the blade. I have found it when I was convexing the edge and on light reflexion. This is purely cosmetic.
Let’s keep in mind, K390 is certainly a very hard steel to work on. I have noticed the same waving on my Pingo

Anyway I can explain now that passionated new love for that venerable knife. It is too long to be acceptable for the Law abide citizen but, what a great tool ! It is much better than my beloved K2: less hot spots and much better blade design from Sal.

This is the same kind of love I got with the extraordinary Bowie from Ed Schempp which shares the same thinness blade wise. I would militate for a K390 Bowie sprint run ! But it seems “Made In Taiwan” sprint runs are rare.

Thinness is good ! Look at that Strudel ! 😉

Here we got a “potentially staining” steel with great (extraordinary) qualities enhanced by a thin thin blade and thin thin geometry saved by a great heat treatment, all is delivered in a slim rock solid package hence the Steel Cheetah’s nickname from my initial review.
This 4th incarnation is an outstanding heir of a great 1980’s design. Sal Glesser is pushing the limits of folding cutlery quietly and gently:
“Integrity is being good when no one is watching.” Such an inheritance !

Spyderco Police C07GP4 – The Steel Cheetah.

I remember one of the very first advertising of the Clip It collection of Spyderco. The Police was presented in its stainless handle serrated edge version of that time (80’s…) and it was written something like: “Pure Performance” … The cheetah is a good example of incredible fast and lean animal and as this knife, it is thin and light and totally performance oriented.

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The venerable Police model designed by Sal Glesser is at its 4th version. Born in the early 80’s it is now part of Spyderco’s Legendary knives. I remember seeing some models with “Pride Integrity and Guts” engraved on their blade: they were the very first. This knife can be spotted in so many Hollywood movies, mostly in the hands of bad guys and even in the excellent classical Spike Jonze’s musical video for the Beastie Boys: Sabotage ! The stainless serrated hollow ground blade was really catching the lights hence it’s success for a dramatic entry in various films !

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I was never a real fan of the first 3 versions of the Police models even if I recognized it has a valuable tool. In my book, the Tantaka was the true heir of those years. The fourth version caught my eye as it was promoting a new steel the KC390.

Many times I had noticed some vertical play on “Made In Japan” folders from Spyderco and decided to buy one if only I could test it before.
But this one came from a Massdrop sale and I was very happy to get one with zero blade play in any direction. Mine feels solid and knowing how strong a good backlock is, this flat long folder is really impressive. So it was about time to review this venerable classic folder which is delivered with a plain edge only and K390 … but why choosing a “staining “steel high performance steel when the Police as always been serrated and stainless ?

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“We make quite a few designs for the Law Enforcement market at this time, so the design for Police use is (not?) necessarily the case anymore, like it was in 1984. I designed the Police 4 to include what I would like in a knife, more than what a LEO might like. It’s still a kissing cousin, and large for most people. I widened the blade, enlarged the hole and selected a steel that I like to use. The design’s success in the marketplace is unknown at this time. But I get to have one. ” Sal Glesser on Spyderco Forums in 2016.

 

Also the blade is perfectly centered. The construction is the same as my Endura and Delica, sandwiching the steel liners with the handle material. Here it’s black G10 on skeletonized liners: the knife doesn’t feel heavy at all but very well balanced and fast in the hands.

The long flat blade is still intimidating while deployed. Let’s see some comparaison pictures. Notice the black could of forming patina in the middle.

Here with Ed Schempp’s Bowie which is one of the best blade/handle ratio folder in the Spyderco collection, full flat ground versus high saber flat ground. The Bowie has been convexed to my taste. The large choil on the police is confortable though.

Here compared to the wonderful Manly Peak, another thin backlock lightsaber. The Manly has not been really convexed; it is really thin ground ! With its S90V blade, better edge/handle ratio and zero blade play construction, it is a real contender to the fourth version of the Police.

They share the same thin stock blade. The Manly (on the right) is even pushing the envelop a little further by proposing hidden nested liners for the same handle thickness.

It is obvious the Delica and the Police are sharing the same DNA even if the Delica main difference is the absence of real choil to choke up the blade. I have both in tip down carry position for easy spyderdrops opening. Here is the Knifecenter special edition of the Delica.

The Delica still got the Boy indentation on the lock when the Police is now leaner. This raffinement has never made a real difference to me. The spring on the Police model is quite strong actually so no worry about unlocking it will chocking the handle.

Here you can notice how longer the Millie handle is compared to the Police. Also the belly of the Millie is much more pronounced. I think now the Police 4 has been also designed to be used while wearing gloves (one of the Military plusses). Both finger holes are equally wide with a very pronounced blade’s hump. The Police’s choil is even wider than the Millie’s !

Also the Military blade is thicker as is its handle. The Police is perhaps more “urban” oriented: it is a large folder easy to wear with any suits.

Here you can admire how the Police is a steel cheetah: lean and mean. The clip was mounted that way and I was tempted to add a deep carry clip but eventually, the spyderdrop is the more handy way to open that large folder so the clip is now mounted near the pivot.

This thin blade enhanced by a great steel (K390) is pushing that venerable model to new heights. We are far from the serrated hollow ground model of the 80’s which was respecting special requirements from the LEO. “It was designed to have an as large as possible blade built into a thin, equally sized handle. Because of this, Save and Serve professionals continue buying the Police Model as an essential tool for their trade.”
From Spydiwiki.

It is a flat and elegant design with a very clever purpose: to insert easily the knife inside the pocket when tip down carried.

Some sanding was required to get the handle even smoother for easier pocketing.
Aerodynamism is one thing, pocketodynamism is another.

Again, never breath that dust it is toxic for your lungs.
“”The benefits of G-10 as a handle material are many. It can support a building, be drilled and sawed. It’s doesn’t retain heat or cold, shuns chemicals, discoloration and peeling. “

And that makes it long folder which can easily be pocketed. Carried tip down, the handle shape pushes my wallet away  when inserted and allow very quick and positive spyderdrop openings. They are four positions to mount the clip on the Police since the 3rd version in 2008.

Next step, with some diamonds, it was time to reprofile the blade to a Manly Peak level and to thin the edge by “deshouldering”. Not an easy task as K390 is a bear to sharpen.

The occasion to picture the blade before to scratch it.

The light reflections on the blade shows it has already started a mild patina while being stored.

K390 develops naturally a beautiful patina like storm clouds. Here is the Police with my Pingo and Urban.

Funny how it is hard to catch on photography but the Urban got the convexed grind I want to achieve for the Police. Both knives are signed by Sal Glesser’s logo.

I have check how the patina was easy to remove before going back to sharpening.

Here you can see the dust formed by the diamonds of a DC4.
K390 is a very wear resistant steel…


Here what Phil Wilson said about it in the Spyderco Forums:
“I have been using K390 from the start ever since it was introduced by Bohler and I got some small samples to try. A bit of history is that it is the European version of CPM 10V but not the exact chemistry (about 1% less V plus small addition of a few others). That is because the CPM 10V chemistry was protected by patent at the time. If you check the K390 data sheet it claims that the bit less V gives K 390 a little boost in impact toughness. It also can be heat treated at a lower temp. than 10v. So it is pretty much the same as the A11 grade but different in a few small details. It is hard to tell the difference between CPM 10v and BU K390 in the real world in my experience. I like both grades and they are the base line (along with Vanadius 10 and K294) from which I measure wear resistance. The 5 chrome is there to make them all air hardening among other things and does not contribute much to corrosion resistance. It is going to make a killer knife in the new offering and be another classic. Phil”

So slowly it is deshouldered but I will be obliged to go back to the blade later. It is, for me, like painting a ceiling… I always come back for another layer… 😉

All right, the performance are already promising. The plastic Bottle Butt is as thick as the blade itself but it has been able to got through it right in the middle. Again, zero blade play on that huge folder: very happy.  Same punition for the bottle neck. The Police shows how powerful it is and that the recipe of “thin blade + super steel” is always a winner for high performance knives. More to come, as this one is going to be user !

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I have mounted a deep carry clip from Blade4sell.

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Pingo Blue C163PBL K390 Exclusive Edge Matters Edition

My first (black) Pingo was almost 6 years ago. Since, Pascal has reviewed his (orange) Pingo… in his entertaining review Pingo Star !
I got the opportunity to get a very rare beast: a blue Pingo with K390 steel blade and studs to mask the tiny trademark hole and protect it from lint.

First I have noticed is the very firm and strong spring in this one, much stronger than my previous version. It is not the easiest opener with stud which is good as it keeps up its legal character: this is a two hands opening knife which can be open with a painful thumb. 😀

Now about the steel K390 is known to me as a friendly steel. I call it an hyper steel !

CHEMICAL COMPOSITION
C Si Mn Cr Mo V W Co
2.47 0.55 0.40 4.20 3.80 9.00 1.00 2.00

The numbers are talking for themselves !!
This is not a stainless steel with carbides forms from Vanadium, Tungsten and Chrome (which is not used for stainless purpose here)…
It will get a patina very quick on daily use (especially eating and cutting meat) and this patina will protect the steel even better. It will show some character in its legality.

What a beautiful tool ! It will be a beater as he name will be Bluebeat !

“Gazing into the heavens on a night as clear as ice
We held our breath
As a new jewel glistens in the Belt of Orion
Out to the west
And parked up on the ridge between all the different lands
I feel I’ve always been here
Do we go back to the city, back to the lights
To the unforgiven world or on into the night
Where there’s always something new to fall in love with
Searching after something new to fall in love with
There’s always got to be something new to fall in love with…”

Bluebeat New Model Army.

So again Spyderco has provided a non locking sub 3 inches spyder with one of the best super “engine” available hence the fun of using it hard!

It can disappear in the watch pocket. There is no reason to leave it behind !

Of course I needed to convex the edge a great deal as I know how stable this alloy is on thin edge. So no fears in making a real blue razor from it.

Spyderco C127PGY Urban K390 – Lil’Grey Alien armed with Hyper Steel.

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Mostly knives company gives the best steel to there flagship models but again Spyderco create the surprise in bringing a 1200 pieces sprintrun of their lightweight Urban slipjoint folder with the best of the best of the cold tool steel: the Austrian Swedish-made Bohler K390.

The steel is a third generation powder steel and to quote them:
“Just as mountaineers need the best equipment to conquer the highest peaks, it‘s essential to use the best materials for your tooling to ensure trouble-free production and achieve outstanding tool life. Three reasons why BÖHLER K390 MICROCLEAN is highly cost effective: Extremely high wear resistance, excellent toughness and very high compressive strength. The high-performance powder-metallurgy steel BÖHLER K390 MICROCLEAN is a reliable solution for your difficult cutting, die-cutting and cold forming operations, and it has a very good track record for applications in the plastics industry.”


Phil Wilson has been using it and he’s known for getting the best of super steels.
“I have been using K390 from the start ever since it was introduced by Bohler and I got some small samples to try. A bit of history is that it is the European version of CPM 10V but not the exact chemistry (about 1% less V plus small addition of a few others). That is because the CPM 10V chemistry was protected by patent at the time. If you check the K390 data sheet it claims that the bit less V gives K 390 a little boost in impact toughness. It also can be heat treated at a lower temp. than 10v. So it is pretty much the same as the A11 grade but different in a few small details. It is hard to tell the difference between CPM 10v and BU K390 in the real world in my experience. I like both grades and they are the base line (along with Vanadius 10 and K294) from which I measure wear resistance. The 5 chrome is there to make them all air hardening among other things and does not contribute much to corrosion resistance. It is going to make a killer knife in the new offering and be another classic. Phil”  On the Spyderco forums.

So one of the best steel is available on a slipjoint the C127.
It’s almost the same cockpit as the Squeak, the blade is a tad under three inches with a full flat ground blade. The backspace is in stainless steel and is used as main spring and the handle are FRN: fiber reinforced nylon. A generous choil gives you security as the blade cannot close on your finger. It’s the same idea as on the C36 Military you hold the open folder by the blade so there is less stress on the pivot. The hump and the choil work as the quillons of a boot dagger. It means also you can give a lot of power into your cuts.

The C127 is modest. This is not the K2. The Urban is a gentleman knife legal in many places. If it was a car, it would not be a Landrover but a Mini.
But here the Mini is turned into a mini Cooper with a very powerful prepared engine as the steel is the chore of the knife.
Again steel is nothing without a good heat treating and without a great geometry adapted to the steel.
And my C127 arrived with a very thin edge. The Maniago naufacturer seems to be very good lately in the way it provide good edges to its blade. Like the Elmax Squeak I was able to cut through the bottle butts with ease and control. The knife cut precisely with not a great amount of force, this is always a pleasure to fill the thick center crossed without the rest of the bottle to collapse due to too much strenght.

Now K390 is not stainless and it suppose to develop a patina. This is good news as it will gives to the knife a lot of character by turning it full grey !

It’s not the first time that Spyderco equipped his FRN knives with the best exotic super duper steel. It was the case with CPM110V on the Blue Manix 2 FRN and the Blue Native FRN . K390 is going also on another flagship: it will equiped the 4th edition of the Police Model. I had the chance to handle it yesterday at the Minimeet and this is going to be a great big folder with a lot of cutting power (Full flat ground large blade) on a sturdy construction (I just regret the did not bring the Power Lock on the Police model, but this is just me…).

For my European fellow have found easily the knife for 77 euros shipping included.
You can use the search functions and do your math and have the chance to try K390 on a very low profile plateform.
I have since mounted Cuscadi Carbon Fibers on this little gem.