The tilting arm mechanism holds the Kinora reel in place during rotation in the viewer. In the 3D design, we used a cylinder to replicate this function. The tilting arm also guides the images in motion.
The metal stop is positioned at the edge of the tilting arm's guidance. Its function is to briefly arrest, separate and flatten the curved image cards. Instead of plastic, we used sheet metal during the replication process to ensure it would function similarly to the original. This also gave us some flexibility to manually adjust its position.
In earlier prototypes, the stop was too visible within the viewer's frame. Through user tests, we ultimately identified the correct position.