Customized version of http://www.thingiverse.com/thing:106381

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=106381

Using the following options:

Washer_Tolerance = 0.25
Washer_Thickness = 0.8
Bottom_Thickness = 1.75
Bolt_Diameter = 5.5
Spring_Outer_Diameter = 9.5
Across_Flats = 5.6
Resolution = 0.5
Nut_Thickness = 2.9
Number_of_Slots = 7
knurl_Diameter = 17
Knob_Height = 5.5