Hi,
Has anyone come up with an easy way to make good looking ventilation holes on plastic (ABS) enclosures?
I'd simply cover both sides of the area to be drilled with adhesive tape, mark the drill holes ensuring these are evenly spaced for good optical effect, support the underside of the area to be drilled with a wooden block, and drill at a very low speed with very little pressure on the drill. Small holes (say 4mm maybe with an even smaller say 2mm pilot hole) work best.
If the drill is too fast, the material tends to melt and clog the drill, resulting in a ragged hole. It is always good if you have some scrap material to experiment with first.