Customized version of http://www.thingiverse.com/thing:299663

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=299663

Using the following options:

height = 28
nut_diameter = 6.25
opening_width = 2
washer_diameter = 5.75
bolt_diameter = 3
outer_diameter = 20
articulation_thickness = 1.5
diameter_bottom = 5.15
pressure_point_thickness = 4.5
diameter_top = 8.15