With the thin special file, you have to deepen the gullet at the same time, not just file the front. That's why I got the file so frequently stuck, but the idea is to keep the same tooth's profile/ dimensions. If you look at the automatic sharpening machines for the band saw blades, they grind only one side of the teeth, but makes a movement to follow the full profile. The teeth end a little bit lower and back, but as new.
For the Suggoï, i found my way : File flat the very tip of the teeth to make them the same high. File the front of the tooth horizontally, then file down vertically (successively for each tooth, same position of the file). Like that, only one side of the file is touching the metal for the main part, so it doesn't bind. Live the back alone because it does nothing for cutting. After all the fronts are done, just a touch on the little bevel at the tips to reduce to nearly zero the tiny flat spots made at the first step.
I didn't found that by myself, I just followed the sharpening technique of the old school foresters by a link showed here years ago.
Two difficult points to ensure by hand:
- Find and keep all the angles right from start to finish.
-Keep all the tips at the same length, or just a few of them will do all the work, leading to a slow cutting and a fast dulling.
