I'm not sure what you have available to you in the Phillipines, but if I were to drill holes into cardboard I'd use a small hobby drill like a Dremel in a drill press attachement.
You can use jewelry supply drill bits in a Dremel or Foredom. You should be able to find 2 mm and 4 mm drill bits elsewhere as well.
If you are only going through one thickness of cardboard you could probably use a hand drill or a Foredom type drill without the press.
Christine ~how-to-make-jewelry.com
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Cardboard Drilling by: Ernie
I use a drill press with a drill for my books but I can tell you that it won't make "clean" holes. They will definitely need some cleaning up after they are drilled.
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Drilling Cardboard by: tony
I find the best way to drill soft materials is to punch it.
If you do not have the right size punch you can do it in a drill press by first clamping a piece of mild steel to the table, then drill the size you want. Next take the drill out and square the chuck end on a grinder.
Put back in the chuck backwards and use as a punch {Do not turn on the drill}
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Drilling in Cardboard. by: Racahel
The best thing I could suggest is a small hobby tool. With a fine engravers tip as it will drill a clean hole if done properly. Hope this helps.
