Comparising measuring methods of pitch diameter of thread gauges and analysis of influences on the measurement results

In this article, the differences between three calibration methods of the thread ring pitch diameter are being presented. Two of these methods are classical methods (executed on a 1D-length measuring machine with a two-ball stylus for mechanical probing and on a coordinate measuring machine also with a two-ball stylus for mechanical probing); the third method is a modern one, executed on a profile scanner to calculate the pitch diameter with an adjustment technique (least square fit).To improve the measurement uncertainty of calibration of the thread ring pitch diameter for classical calibrations the methods were compared, by analyzing the influences on the measuring uncertainty and numerous measurements.The thread ring pitch diameter measurements, which are the main topic of this article, were also incorporated into the international intercomparison, where the same thread ring was used as mentioned in this article.