UltiMaker Z Nut Trap

So I'm in the process of sourcing my own Ultimaker. It's kind of proven to be harder than I thought, there is no BOM anywhere.

So, I've just been making things as I get stuck. Instead of buying a real leads crew, I opted to use an M12 threaded rod and M12 square nut. The nut just so happens to be the same dimensions as the gap in the layered parts.

So here is my solution!

(Don't judge my OpenSCADing, first attempt :P)