jkn submitted this idea :
OK, I now learn that they are called 'shade rings', or 'lamp rings'. So at
least I can get hold of some.

Still interested in a decent 'shade ring tool' or ideas for easing the
turning...

J^n

I don't know if this might help, but they used to sell a spring steel
clip to replace shade rings, stamped out of sheet metal. You just
squeezed its arms and it released the shade.

Another variation used a thin metal spring arms, which you held
together to remove the shade, but the shade needed to have a larger
than normal hole for the squeezed together arms to be able to pass
through. It would be held in place by a normal shade ring.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk