The message
from Al D contains these words:

You mean smoothly adjustable between straight and 15°, yes?

Yes. However, someone has suggested the concept of teeth that engage:
If the joint has small notches or teeth that force the adjustments to
be in, say, 1-degree increments, that would be fine too.

1° teeth would be so fine as to be fairly useless.

--
Skipweasel
Pay no attention to that man behind the curtain.