Abstract: A method of forming a bore through a workpiece with a drill by monitoring drill orientation and bore position; and adjusting drill path as necessary. Adjusted the drill path includes selectively applying an axial impulse to the drill when the drill is in a designated azimuthal orientation. Drill orientation and bore position are monitored with an acoustic transmitter and receiver disposed adjacent an outer surface of the workpiece. The acoustic transmitter and receiver are moved at the same rate at which the drill axially progress through the workpiece, so that they are aligned with the bottom of the bore.