2" Barrel bung with Buttress thread

2" Barrel bung with Buttress thread and 1/2 BSP pipe fitting. I need this for my weed spraying barrels and they are a pain to get your hands on. Fusion 360 saves the day!

I am making a one way valve for my barrel bung that will screw into the bung. You will be able to screw it into either end so it will either be a pressure relief valve or a suction relief valve.

The valve needs a spring, O ring and washer for the end of the washer. The exact sizes is up to your judgement. Take the printed valve and washer with you to the local hardware shop to see what best fits.

If you have any suggestions for different versions I would be happy to design something and publish it.