Improved 2-liter Bottle Tornado Connecter

Improved connector for two 2-liter bottles to allow you to make a Tornado/Vortex. Thread fittings are the US standard 2-liter bottle threads, PCO28 1881. Should fit other bottles with a nominally 28mm OD and a 2.7mm pitch such as 20oz and half liter soda bottles.

Seals most effectively with (2) -020 O-ring (1" OD) for a seal on the bottle mouth.

Oil-Resistant Buna-N O-Ring, 1/16 Fractional Width, Dash Number 020 | McMaster-Carr

The MK2 version has a 120 degree included angle surface on the bottom of the O-ring grooves so it doesn't need supports in the groove. This makes it much easier to remove the supports and improves the sealing surface of the groove. It does need to be printed with supports on the flat surface between the groove and central hole, highlighted area in the picture below.

I have also attached the Gcode file I used to print in my CORE ONE. I used PLA with 100% infill and a .4mm nozzle.

If you put both bottles, one with water, in the refrigerator before assembling they will have positive pressure when they warm, helping to prevent denting.

Flip the bottles over and give the bottles a swirl to create your own "tornado".

Tiny sharks for a shark-nado

https://www.printables.com/model/1561495-tiny-sharks