Also known as Millner-Haufen's "jumbo three,” this multi-purpose trio of 9/16", 5/8", and 3/4" diameter bits is an excellent option for drilling holes larger than 1/2". Millner-Haufen multi-purpose bits work well with a variety of materials, so you don’t have to buy a different bit for each job. Effective on: hardened steel, cast iron, concrete, brick, fiberglass, glass, granite, marble, porcelain, and ceramic.