Following the posts in my '4 Jaw Work' thread, and having suggested that I may try to make an injector,

I've started on making an injector ~ again, out of a billet of aluminium, for no other reason than this is what I have a stock of, in appropriate sizes. I started by doing a sketch from the *LINK* information which several of you kindly provided; to ensure that I had a steam inlet, a water inlet, an overflow & a safety valve which incorporates the outlet to the boiler. That done I put some dimensions to it, which would enable me to access all of the internal parts to fit the pressure cone. (one cone will do for the purpose of the exercise)
So – the body is machined ~ I don't yet have a mill, so some of the drilling was done in the pillar drill and some done on the lathe in the 4 jaw chuck. All of the openings line up and are where I anticipated they would be [internally] and I have bored out the two ends to take the cover caps which I have also made. These will bolt onto two BA studs each. (I do appreciate that the real injector would have more than two fixings, but two on each end is sufficient for this exercise purpose)
My next task is to machine the four spigots for steam in, water in, overflow and high pressurized steam out. I intend to make the cone and the external connections with brass and use 1/4" copper pipework.

Can you please advise on the thread type and pitch for brass gland and compression nuts ?

Thanks
Jack