I can't give all the specifications though.. that's why its so tricky. It's top secret.
The main thing I am wondering is if a threaded rod.. like the blue threaded portion above can move left or right along that path above if you have a a threaded rack rather than a gear rack like above..
OR.. let's say you remove the racks... and you just have threaded rod stock as pictured above.. can the threaded rod in the middle move along there even if the small threaded stock is a smaller stock as in the picture.
Maybe I need to make some more sketchup drawings to illustrate this better.