Thor, or should that be Zeus?

[Neale]

Neale have you ever had a problem with stray chips triggering the sensors? I assume your using inductive not capacitive sensors.

Quick answer is no, but full answer is that virtually all my work to date has been with wood and only a tiny bit of aluminium However, the switches are mounted in fairly well-protected locations. I don't have any compressed air to blow chips around either. Yes, my switches are inductive. My only reservation about them is that the cheap Chinese switches I am using seem to have virtually no on/off hysteresis which makes them slightly less suited to home switch use. It's not a parameter that is ever quoted, though. Still, the IP/M allows me to work around this very easily. I do get very good home position repeatability.