Converted to randall
2 X 1" to 1/2" brass reducing bushes, Bunnings
2 X 1/2" brass plugs, Bunnings
2 X 1/2" O-Rings, Bunnings
2 X 1/4" Push in fittings, Keg-King
Blue plumbers tape to seal thread.
1/4" tap used on lathe to cut thread into plugs to make 1/2" to 1/4" reducing bushes.
Approx total cost = $22 for all fittings, $20 for filter
Thread tapped for free
I hope this helps someone trying to figure out where to get/make the fittings locally. The plugs only get 2 threads, the heads aren't super thick. But it seems to hold pretty well with tape and at worst, thread locker.
1/4" tap, was in a pack of 3-4 at the green shed for $10, with hand tap tool costing $15 if that comes to that.