Day: 04/13/2026

Classification of Accuracy Grades for Granite (Rock) Measuring Tools, based primarily on National Standard GB/T 20428-2006 “Rock Slabs” (mainstream grades are Grade 000, 00, 0, and 1; the old standard GB 4987-85 is the same). The core indicator is flatness, with tolerances calculated based on dimensions and diagonal length. I. Grades and Core Definitions (National…

In next-generation nano/sub-micron precision machine tools, granite (especially high-density varietiee Jinan Blue) is transitioning from an “optional component” to a core benchmark material, comprehensively replacing traditional cast iron and steel. Its core value lies in: extreme thermal stability, supeior damping, zero internal stress, and non-magnetic cleanliness, perfectly matching the extreme precision requirements of semiconductors, optics,…