World's Sharpest

S13, E36: What is the world's sharpest? For severing through an enemy warrior, it's the Katana blade of the Samurai. We'll craft one of these swords from scratch to reveal the secret of its legendary cutting ability. Then we'll put it to the test. We'll also visit Cutco Cutlery, where professionals there hone steel to an edge they claim is the sharpest for chopping food in your kitchen. At Schick, the manufacturer of millions of disposable razor blades every year, we'll find the sharpest edge possible on steel. Add in an industrial chipper that can devour trees in seconds; industrial shredders so sharp, they can gobble anything from a sofa to a fridge; a precision metal cutter that's not even a solid; and a surprising revelation for what makes a sharp piranha's tooth even sharper and you've got Modern Marvels, "The World's Sharpest.