Drill Bit FAQs

How Are Drill Bits Used?

A drill bit is used with some kind of drilling machine. That could be a portable drill or a drill press, a stationary machine used to drill holes more precisely. The drill spins the bit to create holes in the material.

The most common material for drill bits is steel. Steel bits are inexpensive and suitable for boring holes in soft wood. "High-speed" steel bits are harder and therefore stay sharp longer, but they also cost more. Moving up the price chain, the bits get tougher and harder and stay sharper longer. A step up from steel is titanium, then carbide-tipped bits, then cobalt bits, which are extremely hard and disperse heat quickly.

Drill bits come in many variations for specialized jobs. Twist bits allow for accurate cutting. A spade bit is used to drill large holes in wood. An adjustable wood bit allows holes of different diameters to be drilled. An auger bit has large flutes to remove chips and drill holes quickly. A Forstner bit is used for drilling flat-bottomed holes in wood. A drill saw bit is used to drill irregular holes. A left-hand bit is used to extract screws and bolts. A step bit is used for repetitive drilling in various materials and for deburring holes. A masonry bit is used to drill holes in masonry, such as brick and stone.

Drill bit sizes differ depending on where the bits are made, which may make sizing difficult to understand. The size is stamped on the end of the bit that attaches to the drill. In the United States, standard drill bits start at 1/64-inch and size increments increase by 1/64 inch up to 1 inch in diameter. Metric drill bits start at 0.2mm and go up to 25mm.

Drill bits can be used on a variety of materials. The kind of bit you use for a project should match the material to be drilled, such as wood, metal, glass, steel, copper, brass, aluminum or plastic. Masonry can also be drilled, and this includes brick, concrete blocks, glass blocks, and tile. Stone such as marble, granite, travertine and limestone can also be drilled.