A Boring Mill is a machine tool used to increase the size of a hole previously made in a workpiece, usually to obtain a required finish and accuracy in the final hole. In a Horizontal Boring Mill the workpiece is held stationary on a vertical table whose position can be adjusted. A spindle attached to a vertically adjustable head holds the cutting tool, which is fed horizontally into the workpiece. In a Vertical Boring Mill the workpiece is made to revolve on a horizontal circular table as the tool is fed in.