Osmo Borodulin Puukko Review

By Federico Buldrini

This puukko was crafted by Osmo Borodulin, a Finnish hobbyist knife maker from Kotka, a city on the Gulf of Finland, about 130 km east of Helsinki. He doesn’t forge his own blades, so I asked for one by master blacksmith Antti Kuikka  ( antinpaja.fi ) of Nuutajärvi, a small village about 100 km north of Turku.

A small note; the blade stamp is a black-throated loon and “kuikka” is, in fact, its Finnish common name.

blade:
length 95 mm
width 22 mm
thickness 4 mm at the spine
tang 6 x 3 mm at the pommel
steel DIN 56Si7
bevels hollow
edge angle 20,6 °
hardness ~ 58 HRC

handle:
length 110 mm
width 33 mm max.
thickness 25 mm max.

weight:
knife 100 g
with sheath 160 g

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Overview

The blade was forged, by power hammer and eccentric press, from a 56Si7 springsteel bar. This steel is similar to 5160, but has a higher silicon content, improving its strength.
The blade has a flat section, tapering in height, but not in thickness. After annealing and normalizing it was heated in the forge, quenched in oil and tempered in an electric oven. The bevels are ground virtually to zero.

The handle is made of birch bark discs compressed between two 3 mm bronze bolsters. It’s sanded to a fine grit. It’s a bit tapered in width, while the thickness decreases strongly, towards the blade, from about the center of the handle. It has an oval section, shifting into a slim elliptic one towards the blade, the transition following the same principle of the thickness. It’s coated with carnauba wax and polished. It fills the hand well.

The sheath is crafted from 2 mm thick leather, it’s hand stitched and holds the knife perfectly. The back of the seam is painted. It has a pine plywood liner. The wide belt loop is fixed with a big steel D-ring and the loop itself is closed by two steel rivets and glued. As always the D-ring is a good compromise in steadiness and free of movements.

In use

Out of the box the blade was shaving sharp, though not perfectly smooth and with a tiny microchip about 2 mm from the very tip. Stropping wasn’t enough to fix it, so I went with DMT #325, #600, #1200 then strop again. Oddly, I felt like the steel offered a bit more resistance than 80CrV2 at 62 HRC.

While carving a dry cornel troll, I felt a good bite in roughing cuts, with just a bit of struggling when cutting away the bundle of feathers created while thinning down the hat and while cutting end grains. The spine felt a bit sharp. All in all the cuts were always clean and polished. At the end of the work the edge was pristine, but the shaving bite was gone, though easily restored with black and green compound. The handle was always comfortable, quick and intuitive.

While carving the dry silver fir spatula the handle gave its best, allowing for a lot of force to be applied during all the roughing process. The blade, on the other hand, tended to slip while biting fibers with a fore hand grip, especially when working the sides of the spatula. Working using the thumb as a fulcrum and pulling the knife improved a lot the performances and again the big proportions of the handle allowed for a lot of control and force. No problems cutting end grain, while, again, the belly of the shaft was better carved pulling the puukko and using the thumb as fulcrum. I tried also some roughing with a chest lever grip, but the blade replied similarly as with a fore hand grip.
At the end of the roughing process the blade was starting to struggle, the bite was drastically dropped and I detected a roll at the center of the edge. Everything was fixed with black and green compound.
During all the finishing cuts the puukko was fast, effective and never really struggled. The blade only slipped a bit during the smoothing of the flats. The finishing and smoothing of the concave part of the shaft was particularly effortless and fluid, pulling the puukko. The spine was actually a bit too sharp for my tastes and few times was painful to thumb push against it. The handle, again, was very intuitive, very comfortable and easy to work with.
At the end of the carving I detected a new roll in the edge and the shaving bite was almost gone.

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Conclusions

I really liked the handle of this puukko. Its generally big proportions, paired with its drastic taper towards the blade make it both strong and fiddly, with a great easiness in shifting its character. A strong taper towards the blade can be somehow annoying, if the handle is generally slim, but in this case the index was allowed a lot of freedom, while the thicker part of the handle gave the hand greater support. Actually its rounder and bigger proportions make this puukko resemble in some ways an old Pekanpää puukko.
As said, the spine resulted painfully sharp when thumb pushing was needed, so I ended up sanding its corners slightly with #2000 sandpaper. Anyway the sharp edges can work as striker for a ferro rod, if someone prefers to keep them.
The steel reacted as I expected it to. Not really a great edge holding, but quite easy to resharpen and, given the very fine edge, also quite resilient. On green wood I got better performances, but that’s no surprise.

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