Marble v block is made according to national gb4972-85 standard, supply in pairs generally, it is a body of four edges, four working surfaces or four different sizes of 90 degrees groove. Marble v block with high quality "jinan green" stone through mechanical processing and manual fine grinding, with high precision, long life, acid and alkali resistance, not easy to deformation and other advantages, suitable for machining, parts manufacturing industry precision inspection, precision measurement and precision marking, positioning work. Marble v block is an ideal tool for detecting cylinders. The form and position tolerance in the table refers to the flatness of the bottom and the parallelism of the axis of the v-groove to the bottom. If necessary, other surface can be processed according to the needs of precision. 

   Accuracy of marble v block: grade 0, 00, 000.