Surface Finish
Theoretical turning finish, feed for a target Ra, ball nose scallop, and roughness scale conversions.
Inputs
Results
Theoretical values from sharp-corner geometry. Real finish is usually worse: built-up edge, vibration, wear, and material tearing all add roughness. Below roughly 0.001 IPR the tool starts rubbing instead of cutting and the theory falls apart entirely.
Inputs
Results
Inputs
Results
Ra↔RMS uses the ≈1.11 convention. Ra↔Rz uses a ×4 rule of thumb — the real ratio varies from about 4 to 7 with the process, so treat Rz numbers as approximate. When a print mixes scales, get the callout clarified rather than converted.