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:

Bottom_Thickness = 12
knurl_Diameter = 38
Washer_Tolerance = 0.25
Nut_Thickness = 2.5
Number_of_Slots = 8
Washer_Thickness = 0.8
Across_Flats = 5.6
Bolt_Diameter = 6
Knob_Height = 18
Spring_Outer_Diameter = 9.5
Resolution = 0.5