For those that CNC mill their own PC boards I know there is autolevelling software out there to control the engraving depth, but I was wondering if the spring loaded engraving bit holders work instead of going through the whole process of probing the board etc. I can imagine having the holder run over the swarf would cause problems with the height but if you keep everything very clean as you go, don't these devices work? Is there something else making their use undesirable?
Sage