Coving

[WILLWONKER]

I am putting up some coving in a down stairs loo, the problem i have is, i have two internal corners at a cut of 45 degrees, (not a problem ) then a internal corner that the wall swings outwards down to some boxing in, that will be a straight cut. how can i measure the angle of the internal that swings outwards

[jomifl]

not sure if this is the best way but here goes. start off by cutting 2 pieces of coving a bit longer than needed. you will need a helper here,put one piece in position so that it just buts up against the corner, fit the other piece so that it overlaps and sighting from below make pencil marks on both pairs of edges where they meet. then on a table line a straight edge up on each pair of marks and draw a line between them.
It is a lot easier if you can bear a join in the middle of the coving because then yoiu can fit the end mitres on separate pieces and then cut and join to suit. Do the tricky one first.

[Old_Geezer]

You can buy "Magic Mitre Box" which allows you to transfer any angle to the jig and will guide the saw to half the angle. If that's any help.

[jomifl]

sounds a lot easier than my suggestion