Cast iron high-side box requirements: square box of the face can not have rust, scratches, cracks, dents and other defects affecting measurement performance. Sand paint should be non-face, edge chamfering in the side wall box should be signs, and marked with the specifications of size, level serial number, manufacturer name cast iron high-side box Usage: mainly used in parts of parallelism, perpendicularity and other inspection and marking. made of steel with cast iron or concrete 6 face of the cavity is rectangular, with a working surface of a V-groove. generally cast iron high-side box of a very long life, as long as the correct way to use and put security, cast iron high-side boxes can be maintained with the accuracy of face 2 years, cast iron high-side boxes can reduce the accuracy or scraping through the debugging process to restore, cast iron high-side box itself can reach the service life of 50-100 years, so in the process of using the square box to be careful not to wet, corrosion, high and low temperature environments and storage, so that it can extend the life of square boxes, to ensure the quality of work. 
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