Customized version of http://www.thingiverse.com/thing:281520

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=281520

Using the following options:

turn_angle = 150
width = 20
countersink_depth = 2
length = 40
geometry = 8
hole_diameter = 3
turn_diameter = 42
hole2 = 20
hole1 = 0
resolution = 50
thickness = 4