Helix Torus Joint 19 November 2017, 21:00 Sorry, your browser doesn't support embedded videos, but don't worry, you can download it and watch it with your favorite video player! There are a helix groove of one third rev. (n = 1/3) on the big torus. The small torus makes 1 rev. around its axis during 3 rev. around the big torus axis. « previous mechanism Door next mechanism » Escapement load comments Please enable JavaScript to view the comments.