Abstract: A split rotary seal ring is cut from an integral workpiece by forming a kerf which is inclined at a constant angle with respect to axial faces of the workpiece, thereby cutting the workpiece into two mating seal ring segments. The kerf is shaped to provide a 360.degree. radial interlock between the two seal ring segments. The two segments are then moved axially with respect to one another to close the kerf, and one or both of the axial faces are then finished to provide the seal faces of the seal ring. This geometry and method result in a seal ring in which neither the inner nor outer cylindrical surfaces must be refinished after the original one piece workpiece has been split into the two seal ring segments.