Step drills are a universal drilling tool used for sheet metal or metal plates in fabrication or sheet metal working shops. Each step drill can be used for drilling a wide range of diameters; the deeper the drill is plunged, the wider the steps become. Each step on a step drill is a given length meaning the right step drill much be selected for the thickness of the plate or sheet being drilling. Step drills can only be used for drilling nominal diameters (e.g. 6mm, 7mm, 8mm etc).