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:

Spring_Outer_Diameter = 9.5
Number_of_Slots = 6
Bolt_Diameter = 5
Bottom_Thickness = 2
Knob_Height = 8
knurl_Diameter = 16
Resolution = 0.5
Washer_Thickness = 0
Nut_Thickness = 3
Across_Flats = 5.6
Washer_Tolerance = 0.25