In article 1107790649.385217.148810
@z14g2000cwz.googlegroups.com, says...
The problem is not that there was not enough depth for the tap. The
hole is threaded so deep that I run out of male threads on a nipple
before the nipple seals to the manifold. If I run the nipple into the
manifold to just before the end of the male thread, I can actually
"rattle" the nipple in the tapped female NPT hole. All I really needed
here (quality wise) was "good enough to work".
Would I be out of line by asking for a re-run?


OK, the opposite of what I was imagining, they removed too
much material. If you specified a 1/2 NPT thread, they
should remake the parts.

How much pressure does this have to take? If safety isn't
an issue and you're prepared to be cussed by anyone who has
to work on this in the future, a down and dirty solution
would be to make matching nipples with oversize threads.
Another dodge is teflon lined nuts that will seal on the
nipple thread and the face of the manifold. McMaster sells
them.

Ned Simmons