I've watched some You Tube videos abt sharpening these tools, mostly done on CBN wheels, but I've noticed all the tools come off the wheel concaved, if there is such a word, and not straight like they come when you buy them. Does this concave profile affect the way they work? Should it be avoided? Can they be effectively sharpened with a flat diamond credit card hone? Just got my first Bedan tool and don't want to use it for fear of not knowing how to properly sharpen it. Can anyone tell me how they sharpen them, including parting tools, and if the concave matters? Thank you