Reciprocating rack.

thingiverse

A 3D printed mechanism features 507 movements.http://507movements.com/index13.html View a video of it in action here: http://youtu.be/dfs8X2RW-1k Also, check out an animation of its motion: https://youtu.be/Wq4kBHMocGU Designed and printed using Diamond Age PLA on an Ultimaker 1. The longest component is the rack, which spans 241mm in length. Scaling down the design may cause issues for certain machines, so I've included an alternative design that breaks the rack into two parts (rack 03 u and rack 03 l) held together by rack clamps and eight M3 x 10lg button head cap screws. Using a single-piece rack allows you to print it with only eight of these screws. Scaling down too much can result in several problems: Small screw holes may form Some parts, particularly those requiring individual tapping, might become overly tight, necessitating scaling adjustments.