Due to the current interest in nanotechnology, there is a strong desire for comprehensive knowledge on the underlying mechanisms governing the nanometric machining process. This article employs molecular dynamics to study nanomachining in ductile crystalline solids. The simulations are performed using a copper workpiece and a diamond toolpiece where the Cu-Cu and the Cu-C interactions are respectively given by an EAM and a Morse potential. Using a microcanonical ensemble, we investigate the effects of the machining velocity and tool geometry on the nanometric material removal process. The simulations demonstrate that it is governed by slipping along preferential slip systems. Similarities and differences between nanomachining and conventional micro-/macro-machining are discussed.