Several projects have incorporated various metal working processes. The picture shows a part that has several types/ sizes of punched holes in different sizes of "U" shaped tubes.
The left and the right side of the machine move independently but coordinated to accommodate the various sizes of the "U" shaped tubes. Regardless of the width of the parts, the machine maintained the center line of the parts.
The two stepping motors, (the black motors towards the bottom of the picture) created an "electronic gear train" so that both sides move in unison as the part is positioned up and down for determining the location of the various punched holes.
This equipment reamed holes in parts that have extremely tight tolerances. The primary approach to meeting the specifications was to increase the stiffness of the machine.
Stress analysis was used to insure the stiffness of the design while minimizing the "foot print" of the machine.
It is estimated that this design is approximately 80 times more ridged then the machine that was replaced.
Since being placed into production, millions of parts have been reliably produced.