What's the proper way to sharpen a puukko?

[Cosmic Superchunk]

I have been using a Marttiini M571 for the past week from peeling fruit, cutting vegetables, opening packages, whittling and cutting 550 paracord and the edge has needed some touching up, but I cannot get it to the same sharpness it had when new. I seem to have created a secondary bevel, but I've heard you have to lay these blades flat on the primary bevel. Anyone have experience with these Finnish blades?

 

[calyth]

I thought they have no secondary bevels when they're made. That's probably why you have to lie them flat on the stone on the primary bevel and sharpen that.

 

[Joe Talmadge]

I lay the bevel flat on the stone. Scratches everything to heel but it preserves the Scandanavian single-bevel grind, which is why I got a puukko in the first place

Joe

 

[Cosmic Superchunk]

I thought so. Thanks Joe & Calyth. I don't mind the scratches as long as I can get it sharp.

 

[Jimbo]

That's it - just lay the bevels flat on a stone, and go for it. What I'd add is that often I use sheets of emery cloth instead of a stone - supported on a flat surface. Large abrasive surfaces will simply remove steel faster - if you don't have large stones. It can sure take some work (and time)to get the edge flat, straight and perfect. Working through various grits, you can get a fine polish back on the bevel. From then on simple stropping with some fine abrasive such as green buffing compound on leather or cardboard - will keep the edge in top shape.
So you don't need to have a scratched up blade.
If you have access to a high powered lens, you'll see as you remove the factory polish on the bevel that factory grinding is often not all it's made up to be - and just how much work you have to go.

 

[Cosmic Superchunk]

Thanks for the tip Jimbo. I'm going to give it a go with a diamond stone tonight and see how it turns out.

 

[Jimbo]

Marttiini knives generally have blades of suitable hardness for easy sharpening - so it might go faster than I've described.
It's well worth developing the technique of "first time putting the blade into shape" stuff, though. A $5 Mora carbon steel knife will come sharp but the edge will go in no time with any serious whittling of hard wood. Properly set up though, the blade becomes a whole other animal, and mine do a lot of work before I put the edge back to shape with a few minutes with a leather strop and some green buffing compound. By a lot of work, I mean having kids whittle all day with them or batonning through a seasoned log. That's the explanation as to why some of us do well with cheap knives like Moras - and others are puzzled after trying a new one for a short whittling session - and seeing the edge go.