drilling

Common woodworking and metal machinery process that involves boring holes with a drill bit. The commonest kind of drill bit is the fluted drill, which has spiral grooves around it to allow the cut material to escape. In the oil industry, rotary drilling is used to bore oil wells. The drill bit usually consists of a number of toothed cutting wheels, which grind their way through the rock as the drill pipe is turned, and mud is pumped through the pipe to lubricate the bit and flush the ground-up rock to the surface.

In rotary drilling, a drill bit is fixed to the end of a length of drill pipe and rotated by a turning mechanism, the rotary table. More lengths of pipe are added as the hole deepens. The long drill pipes are handled by lifting gear in a steel tower or derrick.