Column for measuring longitudinal dimensions (1) comprising: a supporting frame (2), a carriage (3) capable of moving along a measuring axis (z) along the supporting frame, a cable or belt (40) for moving said carriage along said measuring axis, a counterweight connected to said cable or belt so as to move in opposite direction from the carriage, a guiding surface for restricting the counterweight's movements. A play of 1 millimeter is provided between said counterweight and said guiding surface. This play is sufficient to avoid any contact between said counterweight and any guiding surface when said counterweight is displaced vertically.