I have had great results with a Unibit... as in, 1000's of holes for a small gadget that I make for my side business. They have zero rake angle, so they don't p

I have had great results with a Unibit... as in, 1000's of holes for a small gadget that I make for my side business. They have zero rake angle, so they don't pull through thin sheet material. Keep them as sharp as possible to minimize heating. The bit that I use for plastic isn't allowed to touch metal. If coolant is needed, plain water works just fine. Some oils will craze plastic. Brad point bits also work well. If you're not doing production work, just be patient and proceed slowly to avoid heat buildup.