Summary

My filament often snags and gives me headaches and breaks things. This is a faiisafe

Instructions

Mounts a microswitch behind the Metric Prusa Clip on Filament Guide thing:18889.

Clamp an M8 bolt to the Z-rod top using a bar clamp.
Aim the bolt at the back of the filament guide, and mount this on the bolt end.
Bolt a microswitch onto it and wire it to the killswitch input (I have an LCD thing so I hijacked pin 63 on aux2 on ramps).

When the filament snags it bends the guide back, and just before it snaps the printer stops. More peace of mind for unattended printing.

Filament snag de-headacher