To protect the router bit, I opted for a Z touch plate made of plain printed circuit board copper clad. I re-used a few wires and a small battery charger electrical clamp (shown here dangling) to grasp the router bit.
- It is a thin circuit board I have cut to 12wide x14 inches high.
- I screwed a simple wooden handle on the narrow edge, acting as a wire strain relief
- Simply slip it behind the sled when needed.
- It offers a soft (copper) metal contact surface protecting the router bit sharpness (compared to steel plates)
- It has good conductivity (or the bit can slightly pick through it until it does.)
- Bonus of the copper clad: I could solder a wire directly to it.
Then I found banana connectors to connect wires in a rugged assembly, yet offering easy take away, and safe accidental pull protection without mechanicaly exposing the Arduino shield.
It works overall quite well with the current firmware/GC.
(Note unrelated to that Ztouch plate: I got thin plywood materials (1/4 inch - 6mm) presenting some twitst/bowing preventing uniform sled contact. As a result, the router bit is well calibrated but the surface cuts are showing uneven depth.)