Roll the two pieces with thread-shaped threading plate so that the workpiece surface plastic deformation from the thread.
Threading is two with a thread-shaped thread of the rolling plate staggered 1/2 pitch relative to the arrangement, the static plate fixed, moving plate parallel to the static movement of the circular motion. When the workpiece into the two plates, the moving plate forward rubbing the workpiece, so that the surface of plastic deformation from the thread.
