The majority of industrial drill bits come in two general design categories: twist and insert. Insert drill bits are usually inexpensive and can be cheaply replaced when dull, eliminating the need for drill sharpening. They can also function without relying on a grind wheel. Insert drill bits are relatively easy to use and have a ground structural point that helps to center the drilling operation. However, insert bits can leave a burr at the hole’s exit, often necessitating post-drilling smoothing treatments. Also, if this drill bit breaks it can damage the tool holder, which may need to be replaced.

The twist drill design is a much more common alternative that constitutes the largest portion of drill bits manufactured in the United States. The twist drill bit features a winding, corkscrew flute pattern. The shape and sharpness of the flutes are central to the bit’s operation, and often require sharpening along a tool grinder. Additional worker training is sometimes needed to learn to handle a twist drill bit, but aside from grinder and sharpening costs, an individual twist bit is generally less expensive than most insert drill bits. In addition, this bit has a lower chance of producing burrs in an exit hole, reducing the need for time-consuming deburring treatments.