This paper investigates dimensional errors in stepped solid shafts because of thermal expansion during the machining process. Heat is continuously generated and conducted into a workpiece during machining operations. This heat causes the workpiece to expand which may lead to more metal being removed than was originally intended. The preliminary results showing the magnitude of the deviation of the finished part from specified tolerance limits are presented for an electrical motor gear shaft. An infrared temperature sensing device was used to measure the cutting temperature during the machining process. Using existing analytical models, the measured machining temperatures were used to obtain the deformation zone temperatures and simulate both the temperature buildup and the resultant radial expansion. Actual dimensions were physically measured. The predicted and actual tolerance biases were compared to determine the significance of dimensional deviations.