i noticed abt ur DIY cooler,but then, is ur cooler stable to put a laptop on since u're using a plastic file(light and hallow).besides tht,i've another option on cutting a whole on the file using a razor and the side holes u made at the file.i suggest tht u can use a soldering gun instead(remember those days in secondary school?,alat pateri)when u poke hole already den must clean wif soldering flux.easily obtainable at pudu market.no need use so much energy to cut hole and scared later the knife breaks and fly to ur face if use too much energy