Chamfering machine

The utility model relates to a chamfering machine which comprises a motor, a machine body, a driving mechanism, a feed mechanism and a work piece gripper mechanism. A main shaft of the chamfering machine is fixedly connected with a revolving arm which is provided with a guide slot and a tool apron which radically and alternatively moves along the main shaft in a guide slot, and the main shaft is also provided with an advancing and retreating knife propeller shaft which is in thread connection with the tool apron and a gearwheel driving mechanism which drives the propeller shaft. The utility model not only can automatically advance and retreat knife, but also has the advantages of compact conformation, small volume and easy carrying, and the utility model is particularly suitable for cutting welding grooves of pipeline class parts in repairing site. In addition, the utility model is also provided with a work piece gripper mechanism of the inner expanding type so as to grip pipes of which the opening diameters are big and the external walls are hard to grip.