Turner's Cube
pinshape
Summary This came from watching Brun's video on YouTube, which I highly recommend: https://www.youtube.com/watch?v=AuS6HDHc7XE. It turns out that this is a classic puzzle presented to machinists: https://www.cnccookbook.com/how-to-make-cnc-turners-cube/. The challenge in this exercise was finding a model suitable for 3D printing, approached as a machinist would carve out cylinders from nested cylinders but quickly realized the inside surface of the cubes wasn't ideal. I had to step up my CAD game slightly to get a spherical inside surface. This result is actually superior with 3D printing, which isn't practical with subtractive manufacturing. There are other examples on this site that are inferior because either the inner cubes aren't free to move or the interior of the cube isn't a sphere. Some guy with a fancy CAM lathe might prove me wrong, but my nephew possibly could too. I designed it in OnShape: https://cad.onshape.com/documents/7578e4f3ee04d5c50b0f9ba6/w/8a71c61a2a394945cbf93649/e/0664345b59a74f88c0c675d9.
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