This is crap. They must be sanded by hand. Possibly a blind toolmaker. Expect a job to get them cutting. If you need smaller holes this is for you, initially out of shape, I didn't use it until I've spent a few hours. I guess I'll use them by hand, at least I can finish with a chisel. . If you don't know how to sharpen one of these, you'll get plenty of practice. Good luck, it's better to find one from a manufacturer that has a square or even just eyes in the store.