Z-Endstop for Mostly Printed CNC Int. Version

For long i was thinking about an endstop for the z-achsle of the MP CNC. I think this is a very good solution. I used the reed kontakt of an not longer used bike speedometer and also the magnet. If you use Steel tubes for your CNC i don´t know if this will work but with the aluminium tubes that i use it works very good.