Professional step drill set for commercial or occasional use 4mm - 45mm step drill Step drills offer a significant advantage over cone drills because they offer a positive stop when a hole reaches a certain size Cuts a perfectly round hole in sheet metal Saves time as you don’t have to keep changing the dill size for a larger hole to be drilled Works perfectly on drilling holes in a number of materials including steel, copper, aluminium, plastic etc... Self – starting penetrate, no working and no pilot drill required Manufactured from HSS for maximum strength and durability 12mm flat shanks so suitable for use in most drilling machines, whether, electric, battery or air Total length of the shank – 25mm Double flutes make a perfectly round hole and automatically deburr as you drill For complete performance each time please ensure that the drills are well lubricated, especially when drilling aluminium HRC 62 Drills Self starting design INCLUDES THE FOLLOWING SIZE DRILLS / STEPS • DRILL STEPS – 4mm, 6mm, 9mm, 12mm, 15mm, 18mm, 21mm, 24mm, 27mm, 30mm, 33mm, 36mm, 39mm, 42mm and 45mm