Warning: this is an old but functional version. Check the newer version at: http://www.shapeways.com/model/146656/universal_ring_dial_2.html
This Universal Equinoctial Ring Dial is a portable and self-orientating sundial. You can see how a similar dial works: http://www.sunwatchmaker.com/instructions.php .
You''ll get in position the meridian ring, the equatorial ring and the central bar. The eyelet must be inserted through the "jasolo fecit" part of the meridian ring. The slider is entered through the slit of the central bar and then it is turned with a little force.
For finishing, dip the model a couple of hours in cold tea (hot or warm tea will deform the model). Later, paint with black ink the marks and once dried, remove the ink with a wet tissue (ink will remain on the marks).