Parts I purchased:
1) 1 sheet of 220 grit sandpaper (woodworkers supply).
2) Heavy duty double sided tape (woodworkers supply).
Print and assemble all pieces as shown in "Assembly.skp". After printing, remove the hold down tabs from "Base.stl" and "Top.stl".
Test fit and trim, file, sand, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on the colors you chose and your printer settings, more or less trimming, filing and/or sanding will be required.
Place a piece of double sided tape on the bottom surface of "Wheel.stl" making sure it covers the entire bottom surface, then press the sandpaper onto the double sided tape again making sure it covers the entire bottom surface. Next, using a sharp modeling knife or single bevel razor blade, carefully trim away the tape and sandpaper along the circumference of the bottom of "Wheel.stl". Next place a strip of double sided tape around the circumference of "Eccentric.stl", followed by a strip of sandpaper, and again carefully trim away the excess. These two surfaces covered with sandpaper provide the contact friction necessary to rotate the Ballerina. A photo is included showing a finished "Wheel.stl" and "Eccentric.stl".
Assemble as shown in "Assembly.skp".
Comment if you have questions.