Andrew VK3BFA wrote:
...HOW do I
roll/reduce the diameter of the bigger tubing so its a nice
interference fit onto the smaller size down? - whats the machine
called, can I homebrew one (I have basic hand tools, a welder, lots of
"stuffit - lets try this"...misguided enthusiasm -- well equiped
here...) - any tips, references. pointers appreciated....
Andrew VK3BFA.

It's much easier to expand the smaller tubing than shrink the larger
one with hand tools. You might be able to use a small exhaust pipe
expander. I have used deep impact sockets as a form to hammer tubing
larger and make it round again.

jw