Drilling is a cutting process that uses a drill bit to cut a hole of circular cross-section in solid materials.

Reaming is a sizing operation that removes a small amount of metal from a hole already drilled. It is done for two purposes: to bring holes to a more exact size and to improve the finish of an existing hole.

Counterboring is a method used to create an even surface on the inside wall of a pipe end.

Countersinking is a process that creates a V-shaped edge near the surface of a hole. It is often used to deburr a drilled or tapped hole, or to allow the head of a countersunk-head screw to sit flush or below a surface

The most common application of spot facing (spot facing) is facing the area around a bolt hole where the bolt’s head will sit, which is often done by cutting a shallow counterbore, just deep enough “to clean up”—that is, only enough material is removed to get down past any irregularity and thus make the surface flat.