Yazzo Motor Horn Disc

I need to be able to attach keyed components to the 5mm shaft of my motor.

This thing is a "motor horn" like you see for hobby servos. The primary design benefit is a key notch in one side which will allow you to attach something that has a matching key, like this thing: http://www.thingiverse.com/thing:5867

There is a 3mm hole for a set screw to come in from the side opposite of the notch. I have not placed a space for a capture nut. That can be for a derivative.

In my own usage, I