Threading to a shoulder?

[DianneB]

Well making the top from two pieces worked just fine. The nut was soldered to the sleeve (with the male threads) at the same time the pipe was soldered in. The top and bottom close nicely together now and the check valves work fine. I may file the notches in the discharge pipe a bit deeper to get more cross-sectional area on the discharge when I find my small files (which aren't in the shop) LOL!

[The objective of this whole exercise was/is to improve the performance of the crosshead pumps on my LE American which weren't preforming according to the calculated values, to upgrade the seal to O-rings (to replace the packing glands that were impossible to adjust without stripping the crossheads apart), and to eliminate the flow restrictions in the original design.]

[Builder01]

They look fine. Keep us posted if they ultimately do what you need (or not!).

David

[tetramachine]

Eyeing up the parts, it looks like you can extend the bore for the ballseat a couple threads, then use a parting tool to relieve the last threads at the shoulder.

[Asteamhead]

DianneB,
What about turning an O-ring grove of about the inner diameter of the thread to win both space and a reliable sealing?
Please see a strainer as example of a (very short) cap with O-ring grove. That's my practice proven for many years.
Asteamhead