The purpose of this study was to determine the ratio surface roughness in ST 42 steel with cutting angles , and at speeds 490 Rpm 700 Rpm. This method uses an experimental independent variables, namely angle spindle speed bound steel. To test results using tester tool, which obtained average value a tool 2.848 μm, 2.530 μm 2.423 μm. At 2.439 2.179 2.048 From these data, it can be concluded that...