As the build is in a Public Place I thought too much MDF dust wouldn't go down too well so some of the cutting and driiling needs to be finished prior to Saturday.
Here's the Traverser works:
At top of photo can just be seen the control handle (taken from a Victorian Cabinet Lock). The slot in the traverser is to house the bracket which locates the control rod.
The bracket protudes beneath the Traverser support base so the vertical slot on the base:
1. Provides clearance to enable bracket free movement.
2. Give fore and aft STOP positions (may review this on site).
3. Enables the whole thing to be screwed together as the handle is soldered to the control rod.
The brass runners shown will be fitted at the show with the small screws locating each channel onto the base. The square section brass tube will be CA'd to the Traverser. Hopefully the sliding brass runners will adequately transfer current to the rails. I'll be shocked if it doesn't!