These are real bulkhead fittings, not made up ones.
They are designed to pass fluid through a wall, not into a vessel though. But with the addition of a rubber seal, they work well for that too.
Max pressure is 1000 PSI at 72F !
I used the 1/4" size on my corny steam vessel and with the addition of a seal on the sealing face, it held 30 PSI with no problem. At these prices, why make them up from parts ? (I'm asking myself that too...)
Female Male Panel
Pipe Thread Hole
Size Size‡ Size Each
1/8" 5/8" 5/8" 50785K272 $7.84
1/4" 3/4" 3/4" 50785K273 9.58
3/8" 1" 1" 50785K274 9.72
1/2" 1 1/8" 1 1/8"50785K275 13.49
http://www.mcmaster.com/
McMaster has others. Search with the keyword bulkhead.