Above all - a project like this should be done in a cookie
sheet or plastic tray with a tall rim. That way all parts stay
within hands reach.


Cheap frames have fully threaded screws(from head
to tip) that will work loose over a short time. Better
frames have screws that are threaded only half-way
or so(NO thread facing the surface of the hole through
the arm). Even better ones use a nut flush-mounted
on bottom side of lens frame.