Dial gauge is a metrological tool which uses the rack gear or the level gear operation to transfer the line displacement of the survey rod into an angular one of the pointer hand. Its main usage is to measure the size、the shape and the position error of products.
Dial gauges with in 0.01 mm readings can be calibrated by use of a raster calibration instrument for dial gauges or a alibrator for dial gauges with 0.01mm readings. Dial gauges with 0.001 mm readings can be calibrated by use of a raster calibration instrument or dial gauges or a calibrator dial gauges with 0.001 mm readings. Other methods can be used for the calibration, the accuracy of which should not be lower.
During the whole calibration process the direction of travel of the survey rod must not be changed right in the middle and any adjustment must not be done on the calibrated dial gauge and on the calibrating instrument (or the calibrator). Whether the error in the return ravels positive or negative can be determined in the same way as that for the forward travel running distance.
