Usage: apply to various types of power machinery and equipment and parts inspection, precision measurement, can be used as the measurement benchmark for accurate measurement reference plane and the machine tool mechanical testing, measurement precision dimensional accuracy of parts or deviant behavior, and Precision program line is the indispensable tool in the machinery manufacturing. 
 3, the materials and useful: the material is high strength cast iron HT200, face hardness of HB170-220 after two manual processing (artificial annealing at 600 ° -700 ° and the natural aging 2-3 years), accuracy and stability, good wear resistance . 
 Accuracy: the implementation of the National Institute of Standards Metrology and Verification, respectively, 00,0,1,2,3 five levels. 
 Use color method of tablet surface quality inspection. 
 Scraping cast iron platform for each level are as follows: 
 0, a platform on each side within the range of 25mm square not less than 25 points; 
 Two platforms on each side within the range of 25mm square, not less than 20:00; 
 Three platforms on each side within the range of 25mm square, not less than 12:00. 
 Cast iron platform, and the difference of the stability of the rock platform