Seeing as how I had need of a 50ft turntable but didn't fancy paying £70 or so for the SE Finecast offering, I set about seeing what I could knock up myself.  I've just today got the thing working satisfactorily, so in case it's of any use to somebody else contemplating having a go, here's what I did.  Note that this incarnation is the result of what amounted to a design-it-as-you-go experiment to see if I could do it with just hand tools.  After thorough testing, the bridge unit will be replace