Here is my completed clock. I had a few issues but they were resolved pretty easily. I must have a selected a weak pen spring for the friction clutch. The motor/battery assembly wanted to walk rearward; ultimately contacting other gears and stopping the clock. I created a longer spacer to increase the spring compression and fill the gap to the rear frame which stopped the rearward movement of the motor/battery assembly. The motor that I used is rated at 52RPM@3V. That is considerably faster than the recommended speed. It works, but the flipper needs to quickly pull off the reed switch or risk allowing the motor/battery to wind itself too far and into the other gears. I used the longer flipper, moved the magnet to the center of the reed switch and added the felt pads to the flipper itself. I made a decorative change to the clock face to match some other Craftsman style items that I have. The "interesting" frame color combination is simply because I ran out of brown filament😉. This was a well designed project and fun to build.
Nice. It looks like a chocolate mint.
It is OK to stretch the pen spring to provide extra tension. My next clock has a smaller gap to naturally provide more tension.
It's good to know about different motor variations that can be made to work. There seems to be hundreds of gear reduction options. I should modify the flipper arms to add a pocket on the back side to move the magnet a tiny bit further away from the reed switch. I considered using a mechanical micro switch instead of the reed switch. This eliminates the magnetic attraction, but every switch I tested was considerably louder than the reed switches.
Steve