B.N. Markov, V.I. Teleshevsky, V.A. Sokolov
The article describes roundness errors measurements for fitting round parts based on ISO 12181-1:2011 standard. The article considers algorithms and programs for reference circles calculations using MathCad software. A quasi-circle term is introduced - aninclosing or inscribing curve characterizing the fit.
Keywords: roundness, tolerance, fit, shaft, hole, precision.