I am buying timber to use a curtain batten, between the rail and the wall. So I want the edges to be flat. I see wood sold as 'planed all round' and 'planed square edge'. What's the difference? Which do I want for curtain batten?
Planed all round means all flat surfaces have been planed.
Planed square edge means you have one edge planed straight and can measure from there. It's one step up from rough sawn.
Timber finish terms for reference
Further designations used in wood grading:
Note that PSE is not necessarily the same as S1S. The board edge (narrowest dimension) is planed straight and true with PSE. For Cedar trim, for example, you have a wide dimension planed smooth.
The Red Oak I used for window trim was S3S, made for nice top and sides, would have been pretty rustic for the rough side to show.