Find out if we need more precise homing sensors

[dbenamy]

We're using 3 not-very-stably mounted mechanical switches. The implications of poor homing sensors are that we can't resume a job using home as a way to get back to precisely where we were. Also we may not line up perfectly with the edge of the material.

I suspect this isn't a problem for GVCS tubes and plates. We should do some testing to learn this before spending time improving the sensors.

If we need to swap sensors, we have 3 optical sensor kits with the extra torch table / 3d printing parts which can be easily interfaces with RAMPS.