Ratmandu, to convex or not?

[Danketch]

Hello fellas. Just got my first Bussekin on the exchange. New knife, but not impressed with factory edge. A reprofile is in order. First I was thinking about doing just a straight 17-20* v-grind, but then thinking about it, this knife is meant to be used hard, and convex edges are to me to the best for that. I think I searched and found that some of the originals came with a convex grind. I just got HeavyHanded's new Washboard sharpening system, and am feeling a bit froggy.

What say you Ratmandu owners? Have you convexed yours? Did you rough in on a belt sander? Just convex the edge? Thanks.

 

[Snakebreaker]

I convex all my blades. Much better than a V grind across the board in my opinion.

 

[chiral.grolim]

For heavy work (i.e. lots of metal to remove), if you know how to hold an angle, belt-sander with a very low grit and relatively low speed (I use an HF 1x30 with 80-grit zirc belts).
When you convex, the goal is first to thin the edge-shoulder by blending it back to a higher bevel-height. A simple tip to aid you is to 'paint' the very edge of the knife with bright marker (e.g. red sharpie). As you grind, try to hold your angle such that you always leave a bit of paint at the edge, grinding away the shoulders first. Grinding at low-grit leaves a rough finish which can be polished up on finer belts or by hand (washboard).
Once the knife is as thin as you want behind the edge, then you are ready to actually sharpen it, removing that paint you left at the edge. You can use the washboard to give you a convex edge. I usually just convex the shoulders but sharpen the actual edge with a V on a flat pocket-hone (e.g. crok-stik or DMT plate) for higher cutting performance (i.e. knocking down the convex shoulders close to the apex).

 

[Father & Son Traditional Sharpening]

If you're going to be convexing it, I'd recommend going full height with zero edge geometry….

I originally just convexed the edge seen here, but decided it still wasn't cutting as well as I felt it was capable of without thinning it too much.

Your Ratmandu should essentially have the same factory grind as my Scrap Yard 511 here. It is actually a pretty easy reprofile to this geometry if you have power tools (belt grinder) available, by hand is another story (ask me how I know…. )