CNC special purpose machine is designed and manufactured especially for drilling oil holes of crankshafts. The adopted gun drilling process guarantees high machining accuracy of oil holes. Main movement of the machine is controlled by Siemens 802C CNC system, while accessorial movement is controlled by hydraulic system. With features of high flexibility and convenient mould exchange, the machine is available for drilling various crankshaft oil holes with crankshaft length less than 1200mm.