I just saw a demonstration of the Miracle Blade III at the county fair. The salesman filed the head of a hammer with it. Showed some shavings and said that if it had come from the knife- he's in trouble. But since the knife easily sliced a tomato, the implication was that the shavings came from the hammer. Isn't a hammer much harder than a knife, especially the $20 "surgical stainless steel" knife?