I have it pretty much done and it works
I need to refine a few things. I've got a thin fiberglass base for it to mount to (drying now), to avoid torqueing the assembly. I need to make two new sliders and a new center acutator. These are too thin. I've tapped them to mount the keyboard and it works, but it's only a thread or two. I'm going to pick up some bar stock and make thick ones tomorrow with lots of room for tapping.
I need to cut the drive shaft down and smooth the very tip with epoxy. The threads hitting the support make too much noise. Other then the, looking pretty damn good. I'm thinking of slowing it down. It takes a little less then a second for it to hit full extension. I wonder how much it could move with a better motor. This one is fast, but doesn't have a lot of torque.
So everything should be done tomorrow or Sunday, I'll be posting pics and vids.