Attaching Stations to the Strong Back

The stations (frames) are attached to strong back (building table) using a 2X4" screwed to the table at each station. Then the frames are connected using a 5mm plywood that is attached using machine screws.
There is a 3mm wire running down the length of the table and each frame has a 5mm hole in it.
When the wire has a 1mm space around it the frame is centered and can be attached.