Surface roughness, often simply called roughness, is a component of surface finish (surface texture). It is quantified by the deviation of the normal vector direction of the real surface from its ideal form. If these deviations are large, the surface is rough; if they are small, the surface is smoot

Roundness measurement includes rotary axis method, three-point method, two-point method, projection method and coordinate method. When measuring, make the workpiece to be tested rotate one circle in the V-shaped block, and read the maximum indication value and the minimum indication value from the micrometer.