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:

head_height = 5
type = washer
nut_height = 6
socket_facets = 6
thickness = 0.3
drive_type = socket
wing_ratio = 1
nut_thread_outer_diameter = 9
non_thread_length = 0
socket_depth = 3.5
thread_length = 25
slot_width = 1
inner_diameter = 6.9
nut_thread_step = 2
outer_diameter = 24
nut_step_shape_degrees = 45
texture = exclude
head_type = hex
nut_diameter = 12
nut_type = normal
thread_step = 2
non_thread_diameter = 0
countersink = 2
slot_depth = 2
thread_outer_diameter = 8
head_diameter = 12
resolution = 0.5
drive_diameter = 5
facets = 6
step_shape_degrees = 45