Turley knives are ground with various heights of convex edges. Most people have never heard of a convex edge let alone sharpened one. I prefer a convex grind for a few reasons. 1: It's one of, if not the strongest grinds available with plenty of steel behind the cutting edge. 2: It is amazingly easy to sharpen with a little practice. No set angles to get right every time. 3. A convex grind requires no expensive sharpening equipment to get a hair popping edge and maintain that edge. And 4. A convex edge leaves plenty of steel on the knife for a lifetime of use and sharpening.
Check out these videos for more info on how to sharpen your Turley knife
Sharpening the varied convex grind
You can also search "convex sharpening" on any search engine and come up with several different tutorials. I will say that I personally think a lot of these how-to's over complicate a very uncomplicated process. So don't let all the information intimidate you, it's not that hard.