Abstract
In inspecting the maximum peak to valley height Hmax, which is the vertical distance between the elevation of the highest peak and that of the lowest valley, from a roughness curve, according to JIS B0601, the extremely high peak or low valley, within a certain roughness width, is to be eliminated.
But whether the peak or valley should be eliminated or not, has been required the personal factor, for there has been no trustable standard for the case.
In this report, therefore, twist drill machined surfaces have been prepared to be inspected statistically. Ratios involving extreme values have been applied to eliminate the extremely high or low valley.
At the first step, roughness and waviness have been separated from profile curves. And at the second step, extremely high peak or low valley has been eliminated statistically. And inspected values, Hmax, Hrms and H3 have been compared to the machined conditions.
