Bore a variety of hole sizes with one bit—just slide the blade to the desired diameter and then tighten the screw. These have two sharp edges for faster cuts than fluted bits and won't cause the surface of the material to splinter. A centering point keeps them stable while drilling soft and hard woods such as pine, plywood, and oak. Like standard flat-blade bits, these drill rough holes but should be used in a drill press rather than a hand-held tool. Also known as spade bits.

Prevent clogs that wear the bit and slow down drilling. The flutes on these bits have an open design that pulls chips out of the hole faster than standard spiral flutes. Also known as pole or ship auger bits, they are used to cut deep holes through lumber, railroad ties, and utility poles.

Performance similar to solid carbide but at a lower price point. Like carbide bits, these are stronger than cobalt and high-speed steel and maintain their sharp edges when drilling abrasive material. However, when drilling tough metals like iron and hardened steel, upgrade to carbide for longer life.