Looks like fun! I'm sorry you had to do this in Auto-CAD. I've had the displeasure of having to use it briefly. Must have taken great patience on your part. If the funds/opportunity and time become available, I highly recommend this CAD package for part/assembly design. http://www.solidworks.com/

I've been using this along with Rhino 3d for over 10 years now and they're miles ahead of Auto-CAD in usability and speed. Also there is a new plug-in for Rhino that is pretty hot called T-splines that brings all of it together smoothly.