No self-sharpening on disc blades. They just get a round, blunt edge after a while. You can get a tool called a disc roller that clamps to the disc and draws the steel back out to a sharp edge. In my experience it does weaken the blade; we hired someone to roll the discs on our old Sunflower several years ago and now a few of them are notched, probably from striking something in the field.Why would you need to do this? I don't know because they self sharpen as they wear? What kind of disk?