Customized version of http://www.thingiverse.com/thing:987604

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=987604

Using the following options:

Nut_diameter = 7
Num_spiral = 5
Outer_diameter = 24
Lower_shaft_dia = 5
Total_height = 22
Base_height = 7
Spiral_degree = 45
Show_Cross_section = no
Lower_D = yes
Upper_shaft_dia = 8
Bolt_recess = .6
Nut_position_tweak = 1
Upper_D = no
Lower_shaft_D_depth = 4.5
Upper_shaft_D_depth = 8
Nut_thickness = 2.6
Simplify_printing = no
Nut_type = hex
Bolt_diameter = 3.1