How was this oil fitting made?

[ballard26]

Ended up making an oil fitting similar to RJSakowski's suggestion. All parts were made on 304L to somewhat match the nickel plated brass of the original fittings. Drawings for anyone interested are attached to this post. The only thing I dislike is the the diamond knurl I used. I have a straight knurl ordered and will remake the outer body with a straight knurl when it comes in.

Turning the cylindrical features on the lathe;


Drilling the cross-holes on the mill;
Slitting the screw slots;

Final results and side-by-side with the original;