Customized version of http://www.thingiverse.com/thing:70494

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=70494

Using the following options:

roundness_ratio = 30
wing_h = 2
wing_count = 8
nut_shoulder_x = 2.8
nut_shoulder_z = 2
wing_thick_d = 4
nut_th = 6.6
nut_d = 14.6
hex_nut = 1
thread_d = 8
wing_thin_d = 6
total_d = 45