A problem in the grinding with a small diametric wheel by a machining center (MC) is the decrease of wheel speed. In order to solve the problem, an accelerating unit which increases the wheel speed by the traction drive mechanism is developed. In this paper, a side-cut grinding is performed with a vitrified bonded CBN wheel using the accelerating unit, and the machining error is investigated experimentally and theoretically. Main conclusions are as follows : (1) The machining error can be inferred from the model. (2) The wheel deflections by using the accelerating unit are consisted of the revolving and rotating deflections, and the latter is removed by the truing operation. (3) The increase of wheel speed by the accelerating unit has a significant effect on the increase of machining accuracy.
