Errors in measurement of large diameters with calibrated roller instruments

Conclusions

1. The methodology has been described for determining the errors of instruments with self-aligning rollers. 2. The measurement error has been determined for ID-6 type instruments with inductive reducing transducers. It has been established that the instruments ensure an accuracy of Class 3a-4 on diameters from 1000 to 6000 mm assuming that the measurement error can reach up to one third of the tolerance on the dimension. The actual error of the instruments is considerably greater than that given in the working instructions. 3. The design of the instruments should be improved to enable an accuracy of Class-3. This work is already being undertaken. Preliminary testing of a new instrument, having a transducer without the reducing gear, designed by the Scientific Research Institute for Instruments and Precision Machine Building has shown that the accuracy of such instruments can be considerably increased.