Well, here's the postscript. Finally managed to finish assembling the hollowing rig and here it is…

…and here's a close-up of the articulated section with the taper roller bearings….

I haven't had time to test it on some real hollowing yet which'll have to wait until I get back from a business trip but I'm pretty chuffed how it turned out.
Thanks for the guidance to get the boring done properly!
(Apologies for the clutter in the background).
Jon
Edited By Jon Gibbs on 18/08/2015 19:54:18