GMM wrote:

I guess a small radius would solve most of the wear problem without
causing enormous stretch problems with the carpet but is there
something else I can use, other than a router, that would allow me to
form a radius all the way to the edge? A hand-tool based approach
would seem unlikely, simply in terms of getting a good regular finish,
and I'm not sure that an angle grinder, SDS drill or chain saw would
necessarily do this job, before anyone suggests them.....

I was going to suggest routing just the centre section and leaving 3"
either side square - but Jim beat me to it. ;-)

I would have thought that would let you tart up the edges and have them
on show (so you retain some of the benefit of the hardwood), while
preventing the stair runner for wearing too fast. If you fix the runner
with proper stair rods, then you can also shift it up or down
periodically to stop it wearing too much on the nose in the first place.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/