orrrrrrrrrrrrrrrrrrrrrr something like this
https://www.ebay.com/itm/1pcs-long-1...-/171101789296
$3 + $2 shipping, and would thread into a union nut no probs.
Some specialist fastener suppliers in Oz may hold something like this as well.
CostLessBolts in Moorabbin is where i got a lot of oddball sized stuff like this,
Andrew