Water cooling block

This is my idea of an watercooling block for cheap M6 tubes. Right now it is highly **experimental**. I wanted to reduce weight and size of my hotends to the smallest possible ammount.

If this thing works well you can completly remove the heatsinks on hotends. Then a hotend just assembles from this block, an 1$ china tube, heatblock and nozzle.

It is 16mm height and should be printed as fine as any possible to make the tubes strong enough.

**Features**
- Grooves at bottom and top to fi