Instead of 2D expanding diagram method, this paper presents a new regenerating method for cutter location paths of using smaller tools to produce cylindrical cams. According to the expected motions, cams are put to use in various applications in mechanism. For a cylindrical cam, the roller follower operates in a groove cut on the periphery of an end mill with the diameter same as the roller. By using the conventional method, full-sized cutting tools, will restrict the flexibility of choosing cutting tools for wide roller guide. The manufacture of cylindrical cams is complicate and precise work that depends on the generating method and types of machine tools employed. Since the guiding curve cannot be offset exactly along the cylindrical surface, this leads to some approximating problems. Though the tool-paths generation by using the same size tools as rollers is applied in practice, the study of NC program by unequal tools is not available to meet high precision requirement. This proposed 3D offset-based generating method can regenerate tool-paths for standard cutting tools instead of larger ones and implemented on computerized CAM system. Examples with wider grooves are demonstrated to prove its effectiveness.