Box for an open frame 12V power supply 30 x 37 x 70mm to include a switch on the AC side. DC cord threads out the hole, the AC cord gets pinched in the other opening. The pillars are to wind the cord around for strain relief.

Slip a 20mm piece of 1.75mm filament into each guide pillar to interconnect... nice idea but not so easy. Pillars probably need to be beefier for that or maybe make the holes a little larger so there isn't much friction.

The lid fits tight enough that it holds fast with no glue or screws.

Customized version of http://www.thingiverse.com/thing:1918169

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=1918169

I ended up drilling the DC wire hole out and putting in a DC jack instead of a lead. If I make another I'll change the hole size.

Using the following options:

width = 70
sqCorners = 0
length = 120
hType = 0
hSize = 4
cRadius = 10
lDepth = 6
$fs = 0.3
hSpace = 1
thick = 3
tall = 50