Richard,
Wow, Your experience with Sierra sounds similar to mine with Robinaire. That is actually one of the reasons I got my own machining equipment. That and I just like to cut metal. I do have some basic drawings. SInce I machine everything myself I don't worry about tolerances on the drawings. I will see what I have. I used bevel gears for the rotation which I got from SDP-SI.com. If I did it again I would probably try to use the same method robart uses. All the rest pretty much came from McMasterCarr (clippard actuators, standard bushing etc). I will see what I have for drawings when I get home.
Jeff