Customized version of http://www.thingiverse.com/thing:454702

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=454702

Using the following options:

w = 6.7
P = 45
T = 15
D = 51.7
tubing_od = 8.7
tol = 0.3
number_of_teeth_on_planets = 7
number_of_planets = 3
nTwist = 1
tubing_squish_ratio = 0.5
tubing_wall_thickness = 1.5
allowed_overhang = 0.75
approximate_number_of_teeth_on_sun = 9