To build the pcb drill tool , I used a cheap motor and associated tool to fix the drill bits :

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You can search for the following keywords in ebay : DIY, DRILL, motor

The bit holder on mine was just forced on the motor axis.

You can find these kits for less than 13€ on ebay

You will also need Carbid bits . Standard drill bits are not strong enough to support drilling more than 10 pcb drills ! I would recommend to have 2 sizes : 0,8 mm and 1mm.

you can find these for less than 7€.

Important Note : Obviously this setup is the cheapest , and this will not be able to do anything that a cnc could do. This will only drill small holes ( 0,8 or 1mm ) on a PCB. Also note that there are conditions for this to work correctly: the design of the circuit must ensure that the copper is etched at the point where pcb has to be drilled. This will allow auto-centering of the drillbit, will prevent the drillbit from ripping around, and will give a higher life to your drill bits.  

To build the drill tool, you simply need to print the cylindric holder, using the diameter of your motor.

Fix it to the tool slider Using simple screws.

And that’s it …