If you have a male threaded stud top and bottom, you can attach a female coupler to each and fit a rod or tube of any length that you desire between them.
Seriously, trying to thread a thin wall 16mm dia tube is a huge task.......a typical pitch will be 2.0mm metric coarse and a metric fine maybe 1.5mm so it's quite a bit of engineering!
Often these threads are rolled on by the factory, and of course we can't compete with that.
I'd be looking at the other options suggested here.
John
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