Light Switch Dimmer Knob (for broken switch spline)

Here is a basic switch knob that has been designed to go onto a dimmer switch with a broken spline. A typical spline has two tines (for lack of a better word). This knob with fit on the a spline with one of the tines broken off (as seen in the photos).
I also made a knob that fits on an undamaged spline. See it here: http://www.thingiverse.com/thing:400669