In message , Roger Wareham
writes
bof wrote:


You should just need to cut at 1/2 the angle the corner is, if it's 90,
then cut at 45, if angle is 100 cut at 50, if it's an external angle
it's the same, 270 corner cut at 135; I've done a couple of odd wall
corners with 150 and 120 angles. The only trick needed is to cut the
coving at the angle it will meet the other piece at the corner, i.e.
stand the coving on its edge, rather than laying it flat.

Is this any good?

http://www.magicmitre.co.uk/

Not tried one, I just use a cheap and cheerful mitre saw. The box
attachments on the one in the URL look like they'd make standing the
coving on its edge a bit easier.

--
bof at bof dot me dot uk