Retractable wall hook

What:

3D printed retractable hook

Design is optimized for 3d printing. 

Default part orientation + 6 perimeters wide * 0,40 nozzle shell gives the model proper strength. 

Why:

in 99% a nail in the wall is enough to hang something on it, so why bother with anything extra?

Well, because I can. That's the charm of 3d printing.

I don't have to and I don't want to keep it simple. I don't have to keep costs low since I'm not producing thousands of pieces. I can just create another overcomplicated micro-machine and be happy with the result, even if it's retarded in terms of usability. 

How:

Install the mounting plate first.

When the mounting plate is in place, install the hook with a pin. After that attach the spring and secure everything with a washer: