Abstract: A sheet metal blank is placed at the entrance of a die having a splined interior contour. A punch having a conjugate splined surface enters and passes longitudinally through the die. The splines are formed by passing the blank and punch through the die within an annular space whose contour defines the final spline configuration. Alternatively, preformed splines having a large pressure angle and full corner radii are reformed by multiple passes through dies whose configurations vary to produce shallow pressure angle splines and tight corner radii.