Delica in the Key of K390

 Back before it started, the old gods came together for a meal and to brag about what they contributed the newly forming reality.  Loki/the Coyote/the Trickster was especially gleeful.

“I gave them iron and carbon.”

“So?”

“They mix to form an alloy.  Too little carbon and the steel formed will be soft and useless.  Too much and it becomes brittle cast iron.  If they add the just right amount they get properties all over the place.  And it still rust!”

The old gods thought it was a clever joke on the humans.  All but one, Vulcan/Brokkr/the Master Forger.  Without steel, how could they build things, he wondered.  He crept off and threw a hand full of elements, and perhaps more important, undiscovered knowledge into the mix.

Thanks, Vulcan!

Delica in the key of K390

I just got Spyderco’s K390 Delica and it is quickly becoming my favorite pocket knife.  I really like the Delica/Endura line.  Back in day, I used to fly with two Delicas and airlines had no problem with that.  Even back then those sealed packages of peanuts were hard to open!

I found I could always depend on Delicas and the K390 is no exception!

I’m not really a super steel fan.  Almost every steel the national brands use is hardened and tempered to bring you good performance.  But right now, for a working knife, I suggest you look at K390 steel.

K390 is a tool steel with interesting properties.  Right now, Spyderco is one of the few companies making knife blades with it.  Chemical analysis would find:

Carbon: 2.47%  (Wow!),

Chromium: 4.2%,

Molybdenum: 3.8%,

Vanadium: 9%,

Tungsten: 1%,

and

Cobalt: 2%.

The rest is iron.

It isn't a gamble with Spyderco's four position clip 

 Each of these elements affect the basic crystalline structure of the steel and its properties.  The metallurgy is more complicated than you can imagine.  In its simplest form, chromium and vanadium form small hard carbides that contribute to edge properties.  The remaining elements alter the metallurgical properties.

It doesn’t take a lot of study to realize K390 isn’t a stainless steel.  It is a hard-working tool steel.  And no, you just can’t add another 8-9 %of chromium and make it stainless.  Well, at least if you want to retain the other properties, most of which go unnoticed by the user.  Science tells us why, but that’s just an understand of how the universe work.  For the real reason you’ll have to ask the Trickster.

I like the coarse jimping on the FRN handle

K390 was submitted for an Austrian patented by Bohler in 2002.  Bohler wanted a steel to compete with Crucible’s CPM-10V.  It is not a new steel and gradually found a place among knife makers.

Like all steel, the properties have a give and take aspect and are affected by heat treatment.  K390 is one of the top tier steels with excellent toughness and slicing edge retention.  That is the take.  The give is corrosion resistance.  You need to take care of your steel, wipe it dry and use a good oil.  Spyderco incudes a little handout on caring for the steel.  I’d read it if I was you.

Heading out for Deer camp?  Make sure you take a Spyderco Delica in K390.

Which oil?  There are really two options, food safe and non-food safe.  I tend to lean toward food safe, but I’ve used  penetrating oils too.

I like my new Delica with K390 steel.  Currently all of Spyderco’s K390 steel come with a unique blue handle.  Mike Janich tells me he calls it K390 Blue.

The Delica has a flat grind, which contributes to it’s cutting powers.  Not having shoulders, like the saber grind or it’s brother, Scandi, it doesn’t have to push material out of the way to keep cutting. 

I don't always go off the beaten path...  But when I do it's with a Delica  in K390 steel

The grips are FRN or fiber reinforced nylon.  The fibers, to the best of my knowledge are short glass fibers which strengths the nylon.  The grip sports bidirectional texturing which radiates outward from the center of the handle.  The texturing is strikingly attractive and more importantly, provides increase purchase with wet and slippery hands.

The blade has the trademark Spyderco hole.  I don’t know which is more uniquely Spyderco, the fat tick-like spider logo or the functional opening hole.  In either case, the thumb hole was genius!

One of the major improvements in the knife world is movable clips.  Sal Glesser, Spyderco founder, is credited with the pocket clip he called "Clip-it."  Later versions of Delica and Endura had a reversible clip.  Eventually most Spyderco folders have four-position clips.  I simple love that options.  Most of my knives are carried tip up right hand, but I’ve been known to set up a knife for tip up left-hand carry.  While this may seem trivial to you, this allows Spyderco to be essentially an ambidextrous knife.  Its estimated 10% of the world’s population is left-handed.  Being able to operate a pocket knife with either your left or right hand is amazing.  Unfortunately, many companies have not caught on to this pocket knife innovation.

For me the ability to make a fire by shaving fir sticks and scrapping Birch bark in the touch stone to all knives.  Spyderco Delica have never let me down.

Spyderco’s  K390 Delica cuts.  I cut seatbelt material.  No problem.  Opened packages and bags, cut string and rope.  I shaved feather sticks to build a fire, my personal touchstone of knife performance.  Carboard trembles in its presence.  What a knife!

The suggest retail price is $176.  Right now, all I’m finding on Spyderco website is the full serration:

https://www.spyderco.com/catalog/details/C11FK390/1885 

I suspect if you look about, you’ll find the plain edge on line.

Spyderco K390 steel

It an Endura, one of Spyderco’s top selling knives. But this one is a little different . It has the new K390 steel blade. The flat grind blade is quickly becoming one of my favorite configurations. I grew up with saber and convex grinds but I’m won over by the flat grind. The absence of shoulders makes for easier cutting. If you’re slicing a wedge of Swiss cheese, you may want the shoulders as they push the materials apart and away from the knife. But you also encounter drag. Drag just means you have to put more force on the blade, and for most applications, forcing a blade is never a good idea. So I’m running some test because K390 steel sounds like a step backwards.

It’s not stainless. In fact a product insert warns you to protect the blade.

Bohler-Uddeholm list the following reasons to use their K390 Microclean steel:

1. Good machinability because of uniform mechanical properties,
2. Excellent grind ability even with deep engraving in the tool & die center,
3. Uniform low dimensional change during heat treatment,
4. Non sensitive against overheating or long soak times.
5. Optimal EDM characteristic due to uniform carbide distribution.

EDM is Electrical Discharge Machining and it is becoming industries’ favorite machining and milling tool because it is efficient, economic, fast, controllable and computer-driven. Many of these steel properties, like dimensional stability are a big draw for knife makers.

The Chemistry also looks interesting.

•  C  2.4%,
•  Cr 4.2%,
• Mo 3.8%,
• V   9%, 
• W  1%, 
• Co  2%.

I should also note, new steels aren’t simply made by dumping elements together. Tempering, stress relief and hardening cycles have a major part in any production metal. Still, I find these numbers amazing, especially the 9% vanadium and 2.4% carbon!

Strictly speaking chromium levels should be around 11% to be classified as stainless. Chromium forms carbides that stabilize the microstructure, so in ordinary steels you need an excess of chromium to react with carbon and still have enough to protect against rust. Here you have vanadium to form carbides. So is there enough chromium to form the transparent chromium oxide barrier?  I don’t know.

Let’s play.

I’ve been cutting cardboard all week, I haven’t noticed any loss of sharpness. Today I cubed semi-frozen beef for a future chili dinner. I thought the knife handled better than many of the larger chefs’ knives or the smaller utility knives.

I sliced up some lemons and limes for summer drinks and the knife worked fine.

Tasted pretty darn good, too!

Afterwards I noticed the acid fruit left a start of a faint patina. I could lightly rub it out with a fine metal polish, but I think I’ll keep it. I like a working knife that looks like a working knife.

I increased the contrast slightly so you could see the patina. I'm wondering if it will wear away on it's own.

I think the K390 steel is going to be a winner. I haven’t had to sharpen it yet, but I have no doubt my Spyderco Sharpmaker is up to the job. I understand you’re going to see K390 steel in a lot of other Spyderco products. I also think you’re going to like it.