This is remake of Walter brilliant design http://www.thingiverse.com/thing:604915 & new improved version of my eariler version https://www.thingiverse.com/thing:2398913
Made space to PoE pins, so they don't brake when Pi is insert.
I make the bottom more stronger in before, there are very tight fit if your Raspberry PI don't fit you can scale it to 102 %
The parts are held in together by friction. So no need screws in this case.