Planetary Gear Puzzle Box

thingiverse

Not much of an enigma. Simply turn the dial. Print fully assembled, complete with no supports. Make sure your tolerances are precisely adjusted and that your slicer preserves the one-layer gap in the outer ring gears. After printing, carefully remove the core and separate the ring gears using something sharp like a spatula or razor blade. Update: Increased tolerances from initial version. It is still recommended to print the core and shell separately for the smoothest finish, which is essential for sliding. Updated math has been verified by reality... Gear ratios relative to top (fixed) gear: P1 P2 R1 R2 S1=2P1 S2=2P2 Gear Ratio 8 5 34 20 16 10 1:50 8 6 34 23 16 12 1:28.75 (4:115=5x23) 8 7 34 26 16 14 1:21.6667 (3:65=5x13) We can forget the fractional turns, since it must at least be a multiple of 50 (a whole number) giving us a lowest common multiple of 50x13x23 = 14950 So that 14950 turns of input dial gives: 14950/50 (299 turns of first layer) 14950x4/115 (520 turns of second layer) 14950x3/65 (690 turns of third layer) By my calculation, 14950 turns are required for a complete cycle, this is demonstrated in the accompanying video. That's lower than it could be since all layers share a common factor of 5 in this case (probably due to having five planets).