Thanks for all the replies.
The bolt idea sounds like a good one and I'll check out
floor flanges.
I'm not familiar with phosphorous bronze. I assume this
is a brazing process and not a soldering one? Does this
require an OA torch or is a mapp torch adequate?

This project is just a handrail, not the safety rail, and
will be supported every 4' by a 4x4 post. If somebody
fell against it they'd have to go thru both rails.

Art