A method of operating a stepper motor for use in a dental tool machine for removing material from a dental blank, the method including: a step of adapting torque reserves of the stepper motor at operating points to net load moments respectively. The method includes a first step of predicting, through simulation, the net load moments beforehand; a second step of predicting, through simulation, the supply current to be supplied to the stepper motor for setting up the torque reserves that correspond to the predicted net load moments respectively; and a step of driving the stepper motor based on the predicted supply current.