Customized version of http://www.thingiverse.com/thing:193647

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=193647

Using the following options:

thread_step = 2
type = washer
nut_thread_step = 2
head_type = hex
nut_thread_outer_diameter = 9
inner_diameter = 10.3
wing_ratio = 1
head_height = 5
nut_type = normal
texture = exclude
drive_type = socket
facets = 6
resolution = 0.5
nut_resolution = 0.5
slot_depth = 2
nut_diameter = 12
countersink = 2
nut_step_shape_degrees = 45
thread_outer_diameter = 8
drive_diameter = 5
step_shape_degrees = 45
outer_diameter = 16
head_diameter = 12
non_thread_length = 0
slot_width = 1
nut_height = 6
non_thread_diameter = 0
thread_length = 25
thickness = 2.25