Granite surface plates are high-precision reference tools made from natural stone, widely used for inspecting instruments, precision tools, and mechanical components. These plates are particularly suitable for applications that require exceptional measurement accuracy.
Sourced from deep within the Earth's crust, granite undergoes millions of years of natural aging, making it dimensionally stable and highly resistant to temperature fluctuations. The selected granite material is thoroughly tested for its fine crystalline structure and high hardness. As a non-metallic material, granite is non-magnetic and does not exhibit plastic deformation, giving it an advantage over traditional cast iron plates in terms of long-term precision.
Granite inspection plates are typically categorized into accuracy grades such as 00, 0, 1, 2, and 3, as well as machined (planed) types. These plates are available in ribbed or box-type designs, with working surfaces in rectangular, square, or circular shapes. Surface treatments often include scraping, and special features like V-slots, T-slots, U-slots, circular holes, or elongated holes can be customized according to user needs.
Each granite plate is accompanied by a detailed inspection report that covers essential data such as compressive strength, water absorption, and radiation safety-critical factors in industrial applications. Notably, each quarry typically yields a consistent material type, which helps maintain product uniformity across batches and over time.
During polishing, the diamond tools interact with the mica inside the granite, turning the stone's natural gray color into a deep black finish-this is why most high-precision granite plates appear black after finishing. With increasing demand for ultra-precise inspection tools, granite surface plates have become the gold standard in quality control departments across industries. They are often used as the final checkpoint for product inspection, highlighting their importance in ensuring dimensional accuracy and manufacturing quality.