Self Balancing Egg ( Columbus Egg )

This egg always stand vertically once you release it. It contains at the bottom a 5/8" or 16mm metal bearing ball that shifts its center of gravity close to its wide bottom.

I printed it in its vertical orientation with material support only from the printing bed (that is, no material support inside the egg). When it completed to print the internal cylinder I paused the printing, dropped the ball in, and added some glue from a hot gun (epoxy or any similar glue should also be fine), and then un-pause the printing.

When the printing completed, I cleaned up the bottom with an X-Acto knife and sand foam sponge to round the bottom. Then balanced it by placing on a flat and smooth surface, observing the orientation and sanding slightly the side of the bottom that is too high (the egg tilts *away* from the high side().

PLA, 0.2mm, material cooling fan on, 30mm/s, support from printing bed only (not inside the egg).

If you want to tweak the design or dimensions load the .scad f