Drill bits come in a variety of sizes, both length and diameter, and are used for many different materials including wood, concrete and metal. The size of a drill bit can be specified in both imperial and metric units as well as by standard gauges. Standard gauges can be specified by numbers (wire gauges), letters or fractional units. Twist drills are rotary end-cutting tools having one or more cutting lips and one or more straight or helical flutes.
Drill bits can be based on size or gauge.
Drill bits can be used to create holes for different types of fits.