I haven't followed this thread so this may be a repeat.
Milling "cut outs" in FR4 is milling in glass fibre and it's - glass. You will suffer a very short lifespan of your tools.
I use Karnash PCD or CVD diamond cutters for glass fibre and get 3 times the life compared to a HSS or coated bits.
But quality comes at a steep price... I can buy 40 coated bits at the price of one Karnash cutter.
But if I need 100% precision cuts in FR4, Karnash it is.
On Wed, 27 Aug 2014 12:42:20 +1000
"eric@... [pcb-gcode]" <pcb-gcode@...> wrote:
Thanks, Keith. I'll know for next time.