Spindle DC motor and drill bit specifications for Circuit etching CNC machine I'm making a Circuit etching machine (CNC) and I need a good DC motor and drill bit for the spindle. 

My machine should be able to etch, drill, and cut:


Etching: take copper off the surface like chemicals or a laser would
Drilling: drill holes for THT (through-hole) components and possibly 2-sided boards
Cutting: cut out a piece of the board (cutting a big piece in half or cut a circle out of a big piece)


I'd like to have 1 drill bit work with all 3 functions if possible. Having to switch out different bits is OK but a single bit is prefered.

What sort of specifications should my spindle DC motor (rpm, voltage/amperage rating, ...) and drill bit (material, size, angle, ...) have?
There are several sources of PCB "etching" bits.  They tend to be single straight flutes and high angle, very pointy bits.

For the motor, high speed is good.  Look for 30k+ RPM.  The main thing to be concerned about is the amount of runout, or wobble in the tip.  With a tiny tip, you can't afford much runout at all.  It will broaden the gap you are cutting and put stress on the bit, probably snapping it.

The key to low runout is very careful alignment of the chuck that holds the tip with the shaft of the motor, and a collet chuck to hold the tool.

The power needs aren't high since the speed is high and the cuts are light.  I would think that a 250 watt motor should be way more than sufficient.

The question now asks for drilling and routing, which should work better with the high-speed spindle.  30k is better for the tiny drills than a much slower spindle.  These are hurt by run out.

Usually the drill bits are made of carbide.  For cutting, carbide router or file bits are used.  All drill-bits and router bits and copper cutting bits I have seen for sale have 1/8" or 3mm shank.