Hughie,
I can only think to say 'That's a beast', umpteen questions spring to mind but to limit myself;
What made you want to design and build your own lathe, and
What sort of swing does it have?
OK a few specs. It will swing 900mm + with a 750mm bed powered by 1.5hp single phase 1440 rpm motor. Index capabilities with two discs 15,20,24,30,36,45,60,90. I chose these numbers as they divide equally into 360 with no minutes or seconds of arc to worry about
Speeds , well, with three pulleys there's probably a dozen or more, the slowest is 308 and the fastest is 3210, initially I thought it was 250 and 2800 It currently has no tailstock and vacillate between making one and 'Oh never mind'
The reason, well I guess, 'cos' I can' lol . Also I obtained most of the steel for free. But wanted a dedicate bowl lathe for finishing bowl bottoms via my Longworth or Donut chucks. Both chucks are around 600mm in diameter and I preferred to have them set up permanently on this lathe.
To add to matters I have another almost finished much larger in capacity 1000mm swing and 1.5m between centres. Its of my own design. This one will have 3hp motor and a VSD for variable speed control. This will be my 'go to' lathe although I doubt if I will ever use it to its capacity.
I guess this all stems from my years in R&D, managing a engineering workshop for a global building company. The general idea was and still is for that matter to offer up the plans on a web site that I have yet to build.