E3D Bigbox Z axis endstop

This is a z-axis endstop to replace the default optic auto bed level indicator on the E3D Bigbox 3D printer. I never had the bed level indicator working correctly to get the perfect first layers on my 3D prints and decided to create this part and replace the indicator with a z-axis endstop switch.

Features:
- no drilling, no glueing required on the printer
- simply fits in between the printbed plates
- adjustable with very high resolution
- no backlash/play in the entire mechanism