Hi Maurice
Knew I had one of those fittings tagged and put aside for future reference. The orifice is 1/16 of inch diameter.
Made up replacement by filling with solder and then drilling out the passages to the correct size, sorry no photo of the replacement. Needed a pipe tap to clean out the threads.
Photos show the one that came form my 1945 HUP which was pretty much original. Photos taken during overhaul a couple of years ago.
I replaced it as a matter of practice because I had one break off, another engine, on the test stand and it will empty the crankcase in a hurry. I was standing at the control panel when the fitting broke off at the block and oil started hitting the wall 5 feet away. Killed the engine quick, what a mess to clean up.
Cheers Phil