The paper presents a stochastic model for estimation of the dimensional-errors on the surfaces machined on centerless-grinders equipped with automatic post-process gaging and reset type of feed-back control. Examples have been included to illustrate the use of the model in obtaining distributions of the controlled output (diameter of the machined surface) for different combinations of the inherent variability of the machining setup, the measurement error, the rate of tool wear, the reset magnitude, the ‘lag’, the ‘gap’ and the sample size. These distributions could be used by the designers and the users for economic comparisons whenever there is a problem of choosing one out of two or more alternative control schemes.