I modified an old CNC training machine to work with DeskCNC and have
been happily engraving PCB's for a while now, however the only bit
that I have found that works really well is a M99 carbide spade bit
from
http://www.northbaytechnical.com/ . These bits work great but
are a bit spendy at about US $15.00 each. Does anyone have
suggestions/different suppliers etc they can recommend? I don't think
self sharpening works too well for me as the bits are just too darn
small and brittle. BTW the size of track you can get down to with
these bits seems to be 8 thou or smaller, pretty impressive I think.