A surface plate is a large, solid, flat plate of material used as a reference plane in the process of precision measurement. Surface plates can be made of granite, cast iron, glass, or metal, with granite surface plates showing optimal performance in most circumstances. Some of the potential uses of surface plates include inspection, marking out, tooling setup, quality assurance, flatness assessment, and more. More generally, a surface plate is used as the foundation, baseline, or primary work surface for other precision measurements. Back to entire glossary
