Oxygen replenishment port thread size

[Trevor Laundy]

Can anyone define the thread size on the original build external oxygen recharge port? It is under a small hatch just behind the baggage door on the port side of my 69 PA30C Turbo.

I am spending a fair amount time above FL100 travelling between UK and Cyprus and would like to procure/make an adapter to allow me to fill from European sources away from home. I know that the routinely available oxygen filling hoses do NOT fit and oxygen for small aircraft is not commonly available in Europe anyway, so I want to take it whenever available.

Part No. 23C-47 756-504

Thanks,

[Ben Ayalon]