Abstract
Coordinate measuring machines are devised for most complex measurements. Besides their dimension measuring abilities, the CNC operated machines can measure geometrical characteristics of form, such as straightness, roundness, cylindricity, etc. These are vital features currently, when inspection needs to submit very thorough reports not only on the form, but also on the geometrical features of the given workpiece. Yet the question arises: are these measuring data regarding roundness received from the CMM accurate and reliable enough to be exploited? In order to confirm this statement, the geometrical roundness characteristics were measured on three types of coordinate measuring machines, the results of which were analyzed from several aspects. The results showed a special importance of specific measuring parameters and proved to be independent of the type of measuring machines.