Homebrew PCBs

Hi guys,

I have a fairly accurate CNC machine I built for drilling PCBs but now want to see what it can do with isolation milling.  I am curious as to what I can expect for the minimum trace width/ spacing?

The machine itself should be accurate to within .0005" (13 microns) as it uses linear encoders of that resolution.  The spindle does have a bit more runout than I would like as it is about .0015" (38 microns)

If you have recomendations for an engraving bit supplier I sure would appreciate hearing your suggestions on that too.

Chris