Pipe flare, aeroport for subwoofer port vent or any other PVC pipe that needs a flare

I've been looking into ported sub boxes lately and saw a few ways to flare ports to reduce chuffing, this is my attempts at making a flare form quickly and a failed attempt at doing it without a form - inspired by a video of someone doing it with a hand drill over a gas stove. Edit is a bit lazier than usual, don't have much time for such things.