Rsk (skewness)
Asymmetry of the height distribution: negative means valley-dominated, positive means peak-dominated.
Negative skew (valley-dominated) suggests a plateau-like surface that carries load and holds lubricant; positive skew means sharp peaks that wear in. It is not a finish-quality grade on its own.
General shop guidance in our own words. The drawing and the standard it cites decide; verify on a sample part.
Typical finish by process and the turning feed and nose-radius formula: Surface finish guide.
Related surface roughness parameters
Tell the advisor the feature, the tolerance on the drawing and the material. It answers with machining choices, brand-neutral.
Definition written in our own words and checked against engineersedge.com. Symbol and term names follow ISO 21920-2; we do not reproduce standard text. See the full index.