Square cushion boxMainly used for checking and marking the parallelism, perpendicularity, etc. of components, it is a hollow cube made of cast iron with 6 working faces, one of which has a V-shaped groove.
Square cushion boxThere should be no rust, scratches, cracks, dents, or other defects that affect the metrological performance on all working surfaces. Non working surfaces should be sandblasted and painted, with chamfered edges. There should be labels on the inner wall of the square box, indicating specifications, dimensions, grade, factory number, and manufacturer name.