Korpisoturi-puukko, a brief introduction to The Better Blade
Hello everyone! Happy to be able to finally introduce the project we have been silently building for five years total, and as Rokka Knives Ltd. since september 2018. Our goal has been to modernize the Legendary Finnish universal tool - Puukko-knife - while staying true to handmade originals.
What makes a traditional Puukko-knife in our view?
-carbon steel blade with a rhombic cross section geometry - result of the forging process
-often rhombic cross section tang, again because of the method of forging
-gentle taper from the shoulders to both directions
-selectively hardened cutting edge, with a tough, springy spine
-hard cutting edge
-through/hidden tang construction
-high flat grind (about 2/3 of the blade)
-no secondary bevel
-relatively aggressive edge angle (17-22 degrees)
-the knife should be both functional and beautiful, although we know it’s in the eye of the beholder
-sturdy, yet lightweight
-fairly small overall size
-moderate blade length
As you can see, it’s a extreme combination of characteristics.
Puukko has had a growing following both in Finland, and lately also abroad. We LOVE traditional Puukkos, so the pressure has been on - how to go about tinkering with a time tested and revered design, respectfully.
Our goal has been to create a Puukko that remains true to the defining characteristics of the originals, but introduces upgrades in areas where many people have been asking for them. Furthermore, we wanted the end product to be as close as possible to 100% Made in Finland, including manufacturing and the components needed for the manufacturing process. Korpisoturi-puukko is proudly Made in Finland!
Choice of steel
We decided on Böhler 80 CrV2 early on, because it is a well understood, and overall a excellent tool steel that can be used to produce high performance blades when masterfully heat treated, and used in a proper context. Our bladesmith has used 80CrV2 for years, and it is highly regarded by many custom knife makers around the world. 80 CrV2 is a ”simple”, yet excellent carbon steel, and that fits the bill perfectly when it comes to a Puukko blade.
Blade
Rhombic geometry runs through the entire form of the blade and tang. There are no unworked surfaces. This made the process of designing and producing the jigs, and the injection molds interesting, to say the least. Grinding of the blades was also quite complicated, but, thanks to the great level of professionalism and expertise at Laurin Metalli Oy a working process was found. The blade and tang of Korpisoturi both taper towards the tip, as they would on a handmade Puukko. On a Korpisoturi-Puukko this has been done to shed weight off of the 5mm thick blade.
Heat treatment - method by Finnish metallurgist Juha Perttula;
the entire element hardened and tempered springy, about 50 HRC
cutting edge induction hardened and tempered to 63 HRC (+/- 0,5)
the ”glass breaker” at the tip of the tang induction hardened and minimally tempered to achieve maximum useable hardness
The edge angle is about 19,5 degrees to make the knife bite suitably aggressively, without taking away too much from edge retention.
The handle
Typical criticism against traditional Puukkos is the shape of the wooden, or birch bark, handle that seems slippery/dangerous at a glance. The lack of a finger guard has been a concern for many. We do not necessarily think that this is a problem, but, decided to shape the handle of Korpisoturi to reflect modern preferences. Simultaneously the shape of the ”guard” gave us an opportunity to use the feature to secure the knife into it’s sheath properly - lack of a clear locking mechanism being another point of criticism against traditional Puukkos with friction type sheaths (not to be confused with ”naksutuppi”).
Korpisoturi has a softly contoured injection molded TPE Dryflex handle, hardness 80 Shore A. We shaped the handle moderately, understanding fully the philosophy behind simple Puukko handles; more shape you add limits possible grips, and makes the knife less friendly on the hand in extended use.
The sheath
Instead of a wet formed leather sheath Korpisoturi has a Kareline natural fibre composite sheath that does not absorb moisture, is machine washable and withstands a wide temperature range (-30 to +100 degrees celsius). Kareline is probably best known as the material for the Kupilka outdoor kitchenware. The sheath is ambidextrous - with points for the attachment on both sides - and is compatible with various retention mechanisms, than can be set on different hights according to the users preference. It comes with a short Tactical Tailor Malice-clip for pals/molle compatibility. For a more traditional belt carry a longer version of the Malice-clip can be purchased.
Just like many handmade Puukkos Korpisoturis sheath is a ”naksutuppi” (rough translation; clicking sheath), which clearly indicates a positive lock with a click.
We are proud of what our team has achieved so far, and hope others find our work interesting and worthwhile. That said, we are far from being done - Korpisoturi has many surprises yet to be revealed.
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About Rokka Knives
The project was originally a brainchild of three Finnish Puukko-enthusiasts who thought it was about time to update every Finns favorite outdoors tool. For the first three years or so it was all very much ”shoestring”, but has since developed into a actual company - albeit a tiny one, still. Officially Rokka is a one man operation, but all six owners are committed to making it grow. Read, only one is actually getting paid, and others are working for the sheer pleasure of it.
Our team is from a wide range of professions, which has allowed us to do many things independently. Except websites, which is instantly obvious.
In addition to the Korpisoturi-Puukko we already have several products in the pipeline. More about that later.
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Rokka Knives would like to thank all the great (and great many) people who have helped us and cheered us on for years. You rock, we know who you are, and we will not forget!
We would also like to thank the great folks at;
@laurinmetalli
vesuto.fi
@plasthill
@3dformtech
@fckoneistus
@niinimakirdps
Without you none of this would have been possible.
We would also like to extend our immense gratitude towards all the experts and organizations without whom Rokka Knives would already be a smoking crater in the Finnish startup soil:
@businessmill
@businessfinland
@finnvera.fi
@etelakarjalanyrittajat
@wirmalappeenranta
Finally, we would like to thank a great group of professionals who have been heavily involved in the development process of Korpisoturi from the very beginning.
