Abstract: Apparatus (A) for realizing a measuring device (D) includes workbench means (1) and a bearing structure (2) for at least a sliding operative head (4) with respect to said workbench means (1) on guide means (3) carried by said structure (2); said workbench means (1) having at least a flat surface (1a) on which a natural granite element (R) can be placed; on said element (R) a graduated glass plate (L) is being partially overlapped and firmly coupled and fixed to form the said measuring device (D).