The Makelangelo 3.0 has a pen holder that is an off the shelf part. Because of a lip on the end of the holder, it makes it difficult to easily mount the pen. So I created this chuck and holder that screws onto the servo horn. Print out the two chuck pieces and mount the collar with the arm onto the servo arm. Mount the servo onto the plate. Insert a sharpie pen and the screw collar. tighten till pen is clamped. you will need a modified version of the support plate.