BALL STEP GAUGE

摘要

A ball step (10) formed by drilling a plurality of holes (6), in which balls (5) are inserted, at specified intervals along the axial direction of a horizontal frame (4) of a gauge frame body (1) having an H-type cross-section, providing a plurality of grooves (7) around the holes, and press-fitting the balls (5) in the holes so that the centers of the balls are aligned with the neutral axis of the geometrical moment of inertia of the gauge frame body, whereby, because a variation in ball intervals of the ball step is very small, it can be used as a measurement standard for calibrating a reliable three-dimensional measurer.