Cube Gears

thingiverse

This design was initially a practice in utilizing Greg Frost's incredible involute bevel gear script (http://www.thingiverse.com/thing:3575), but it evolved into an appealing worry-ball type object that is also inspired by Greg's broken heart (http://www.thingiverse.com/thing:4683). The gears in this design are octahedral, allowing them to mesh with each other and spin. A unique feature of this design is the ability to grab two opposite gears and twist them, making the center with six other gears spin rapidly around. To print, use a stock TOM without rafts or fill (but with extra shells). Assemble the parts by screwing threads into the central block first, followed by attaching the gears ensuring that the cube edges connect them. If the gears are too tight to spin, simply unscrew them slightly. The OpenSCAD file is highly customizable for different proportions and screw sizes. To change the gear teeth ratio, use Matlab or Octave with the provided gearopt.m file and copy the result into the OpenSCAD file. Note that this is necessary due to OpenSCAD's limitations in handling iteration loops. For more information on involute gears, check out the MCAD library used in this design (https://github.com/elmom/MCAD).