Tim Wescott wrote:
(snip)
Find the appropriate sized tubing and thread it yourself?

Thought about that, but the time involved for me to do it by hand (no
lathe) would make it unprofitable.

How deep do you need the threads on the inside-threaded part?

We were thinking all the way, but that was just a preference.

Threading some varieties of stainless is a real treat, if you like
cussing and broken taps. I'd check McMaster and other sources out there
for what alloys are available, then I'd check back here for what may be
machinable.

If your outer-threaded parts are short enough you may be able to drill
out screws.

I think I've convinced my partner on this project to go with brass now.