In the Uk at least 4x2 is not always 4 inches wide and 2 inches deep. Crazy I know,
that's where the terminology comes in, which I will hopefully provide links to later
starting at the largest here are just some of the different 4x2's
-4x2 rough sawn, this is more of a fencing material and is very rough to the touch, It is nearly "full dimension" e.g 4"x2" or 100mmx50mm
-4x2 regularised, this is usually sold in either treated or untreated (green or not) and has been planed on all sides with the corners rounded, will usually end up at about 90mmx45mm or 3 3/4"x1 3/4"
-4x2 CLS (Canadian lumber standard) looks very similar to regularised but is even smaller usually around 87mmx 38mm or 3 5/8 x 1 5/8
-4x2 PAR/PSE (planed all round/planed square edged) this is more of a joinery type material usually without treatment and square corners but very smooth. this usually comes at about 90mmx 45mm
-then there is the option of strength classification C16, C24, T26
-options on joinery grade material 4ths, 5ths,CVG
the list goes on and hopefully it will get filled one day
but for the moment just make sure you know what you are asking for
HTH
Ed
