Fused silica, which is used widely in optical systems and is an ideal glass for windows in space-vehicles and wind tunnels, is selected as the test material. Its mechanical properties are given in Table 1. The experimental conditions used in these tests are shown in Table 2. The micro-topography of the machined surface was examined by using a white light interferometer (WYKO 2000), and the micro-cutting force was measured by a piezoelectric dynamometer (Kistler 9254) mounted under the tool holder.