Making a test ring

1. Similar to what has been done in other projects, add a Boolean modifier to the ring and difference the Finger object from it. The Finger object obscures the effect of this operation, so hide it. One way to do this is to select (right-click) the Finger object and navigate to Show/Hide | Hide Selected from the menu at the bottom of the 3D View Panel Object or press the H key. Another way is to click on the icon that looks like an eye in the Outliner on the line for the Finger object:

   

2. The ring is now perfectly serviceable, but there's no harm in making it a little more appealing. Enter the Edit Mode (Tab). Again, notice that without applying the modifier, its effects are undone while in Edit mode. Loop Cut (Ctrl + R) the cylinder around the middle-click and left-click twice when selecting, so the slice does not slide up or down:

   

3. Scale (S) the newly sliced ring slightly outwards. The scaled ring of points should not extend more than 1 mm (one small grid square in the background...