Drill bottle cap for PET bottle bump removal

Based on a Coke cap, this is a simple electric drill attachment to facilitate rolling a PET bottle over a stove or another heat source, to flatten all the bumps.

It's made to be used with a M8 screw and nut.

To airtight seal the cap, I pored some hot glue into the space for the screw hat and pressed firmly. You can then apply some more hot glue over to seal everything even more.

Than I added some super glue on the outside before tightly secure de nut.

Successfully used with other bottles, not only Coke ones, so I'd say that is pretty versatile.