The micromechanical clockwork part is cut from a plate-like silicon substrate. The cut edges of the part include portions intended to serve as contact surfaces arranged to slide against corresponding contact zones of another micromechanical part in a clockwork piece. The cut edges have a ribbed surface including an alternating set of ribs and furrows, the ribs and the furrows being straight and each contained in a plane parallel to the plate. Moreover, the ribs and furrows which the cut edges have form a stepped pattern on the cut edge, with first intervals in which the spacing separating the ribs from one another is equal to a first distance, and at least one second interval in which the spacing between the ribs is equal to a second distance different from the first distance.