About this 3D model
Original blog post: <a href="http://zheng3.com/2012/06/16/switching-gears/">Switching Gears</A> No assembly necessary. Just print and play. The bores on the gears should be a snug fit on a 1cm shaft, but not so snug that a child can’t easily attach and remove them. A piece of sandpaper or masking tape will help adjust the bore and dovetails to the desired tightness. The gears have 32, 16, and 8 teeth, respectively. Computing gear ratios is left as an exercise for the reader.