This paper focuses on determination of uncertainty and individual contributions to the measurement uncertainty on the nano-CCM NNM-1 instrument fitted with the touch-probe scanning system Gannen XP. Ruby ball diameters with various nominal diameters are used as the measured objects. Two main methods to determine the measurement uncertainty, the substitution and multi-position methods are addressed in detail. The paper also summarizes and specifies calculation methods to determine the measurement uncertainty, and provides results of representative sets of measurements, including determination of the expanded measurement uncertainty, in a new, unpublished way.