A recently developed finishing process using a rotating magnetic field is known to be very efficient for the finishing of parts such as vacuum tubes, sanitary tubes, etc, which are difficult to be finished by conventional finishing methods as they are generally curved tubes. However, the finishing system using a rotating magnetic field has the defect that the cross-section of the workpiece can only be circular because of the internal rotating tool. Therefore, a new finishing process for workpieces of nan-circular cross-section is required. Magnetic abrasive jet machining is a new concept in finishing processes, being a precision internal finishing method using a working fluid mixed with magnetic abrasives, which is jetted into the internal surface of the tube, with magnetic poles bring provided on the external surface of the tube. In this study, the new-concept finishing process, or the magnetic abrasive jet machining system, was developed. The machining conditions were predicted using simulation and some characteristics of the finishing process were analyzed. (C) 1997 Elsevier Science S.A.