Took my 3mm thick FC plate to fablab where they have nice cnc router, wanted to cut out some arms for quadcopter frame. All went well but the router bits did not last long. I never used that sort of machine before, so i have few questions, first of what kind of bit i should use for CF ?

Carbon fibre sheets will very quickly kill any router cutters that are not Carbide .. even TIN coated milling tools get blunted very fast .

This is precisely like milling or routing glassfibre printed circuit boards .. 

The same goes for drilling a lot of holes .. the drill has to be Tungsten .. or it will not last ..

Very high speed and sharp+hard tools !!    That is why Water-jet is very good!  It will leave nice edges (not perfect) and if you make sure to start the cut at en edge or at a point on the sheet that will not be used, it works very well.

I have invested in a few tungsten end mills for my Non-CNC milling machine to handle this sort of stuff .. 

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