stuart noble wrote:
The Medway Handyman wrote:
M wrote:
Hi,

I've been doing a bit of landscaping over the summer (?) and have
terraced my garden with a few low retaining walls. My intention was to
buy some stone (or concrete) blocks to work as coping stones, but I've
failed to find anything suitable and so have bought some preasure
treated wood to do the job instead.

Having messed up some skirting a few years ago by not correctly
measuring the angles of the corners of the room and assuming them to
be 90 degrees (please, nobody else do this) I would like to get the
wooden wall tops fitted with tighter joints, but how do I accurately
measure the angles?

Not sure I understand. Is the timber going on top of the wall in the
same way a coping stone/stones would?
Does anyone have any foolproof techniques to measuring internal or
external angles of walls for use when calulating mitre cuts? Ideally
i'd prefer some method whereby I don't have to go out and buy a
special angle measurement tool (ashamedly I don't even have a sliding
bevel), and i'd even consider maths as a way out so long as it works!

As others have said, you don't mitre internals when doing skirting
boards, you scribe them.

Going back to the garden walls, if the timber is going flat on top
like a coping stone would, there is a simple way of doing it, which is
harder to explain than to do.

Lets say the two walls are like a capital 'L'. The angle may be 90 or
88 or 92 it matters not.

Cut a board for the upright of the L with a 45 mitre at the end, call
it piece A. Leave this to one side for the moment.

Place a board (B) on the crosspiece of the L of appropriate length.
Place board A on top with a scrap piece of timber under the other end
to keep it level. Adjust the boards so that they align with the
walls, then mark a pencil line on board B along the angle of A.

Cut along this line and the boards will fit. The join will match the
wall angle whatever it is and the mitre will fit. It won't be a 90
mitre but it doesn't matter.


But then the two angles won't be the same, and therefore neither will
the length of the cuts. Rather like coming round a 135 bay with 1 x 90
and 1 x 45
To extend Dave's method, once again more difficult to describe than do.
Take the two pieces of wood you want to use and lay one piece on one
of the walls as you would want it to be, with one corner over the
outside of the angle of the 'L'. Lay the other piece over it,
supporting it so that it is horizontalso that the outer corner is
exactly over the outer corner of the first piece. At the inner part of
the corner mark both pieces of wood. Cut both pieces from the mark to
the corner and you have bisected the angle.

I have used this method with paving slabs to turn a corner. Thry it
indoors with card to convince yourself

HTH

Malcolm