Which of the following statements best defines 'depth of cut' in lathe work?

Correct Answer: Option D — The distance from the bottom of the cut to the uncut surface of the work piece.

Depth of cut is defined as the perpendicular distance from the machined surface to the original, uncut surface of the workpiece. It represents the actual thickness of the material layer removed by the cutting tool in a single pass, directly influencing the material removal rate and tool load.