International comparison of high-accuracy roundness measurements

An international comparison of roundness measurements at the highest level of accuracy has been carried out between eight European laboratories. Three roundness standards with different designs and roundness deviations were measured. One standard was a commercially available type, two standards were developed for the purpose of this comparison. The agreement between the laboratories was within ±20 nm for the standard with the smallest roundness deviation. The comparison was sponsored by the Commission of the European Communities.