Abstract: By combining shaping and milling actions, or smilling, the cutting tool can move through the entire usable portion of the spline and machine a tool relief into the face of the adjacent feature such as a shoulder before retracting, reversing direction, and repeating the cycle. The smilling apparatus and manufacturing method eliminates the need for an annular spline relief and the full length of spline engagement can be utilized for strength. The effective width of the spline connection apparatus manufactured by the smilling process conserves space and increases the load carrying capability of the spline connection.