Adustable Z Endstop trigger (quick solution before printing something more permanent)

I made those for a 3D printing course I attended at the FH Kiel.

We used sheet metal to trigger the opto-endstops. It was difficult to adjust and the sheet metal cuts through wire insulation when they get tangled up...

This is nowhere perfect, but allows to adjust both position and stopping point.

The earlier version used a ballpen spring, but it works with just as fine with a (M4) screw and a nut if the parts fit snug.

The various holders can be fixed with M4 Screws and the round pa