Yihailong Cast Iron Welding Riveting Platform with Stable Accuracy, Customizable Cast Iron Plate, Cast Iron Right Angle Ruler, Cast Iron Straight Edge, Cast Iron Ruler. No restrictions on specifications, standard sizes available or custom orders accepted. Welcome to call for consultation at 18998432400, Mr. Zheng.The flatness of the inspection platform can be divided into: ①AA grade: Its flatness (μm) = 1 + 1.6D2 (D is the diagonal length or diameter of the platform), used for highly precise measurements, often in laboratories; ②A grade: Its flatness is twice the error of AA grade, commonly used in tool inspection rooms for precision measuring tools; ③B grade: Its flatness is four times the error of AA grade, often used in tool inspection rooms or on-site for inspecting measuring tools or marking. Inspection plate accuracy: Executed according to the national standard metrology verification regulations, divided into four levels: 0, 1, 2, and 3. Inspection platform specifications: 200mm×200mm - 3000mm×6000mm - 1000*2000mm - 1500*3000mm*3000*2500mm - 4500*6500mm, and other specifications.