Actual dimensions of a 6 x 14 piece of lumber....5.5 x 13.5????

Question

Hi,
What would the actual dimensions be to a 6 x 14 piece of lumber? I am guessing 5.5 x 13.5 inches, or is it 5.5 x 13.25 inches? Why are the dimensions not actually 6 x 14? This question has been driving me crazy.

thanks,

pb4sc

Answer 1

There may be a little variance between runs... 1/16th of an inch isnt unusual.... if you want an 'exact' measurement, you'll have to actually go buy a board, lol. An approximate measurement would be 5 1/2" x 13".

And no... it's not because of 'budgit cuts'.... it is because of the standards agreed upon by the lumber industry. A '2"x4"' actually starts out at the lumber mill as a 2" x 4" rough cut. The person who has their home built with studs that are actually 2 inches thick... that home was probably built with 'green' lumber.... it was not kiln dried.

Lumber shrinks when it is dried. This is a fact of life, and cannot be gotten around... it is its nature. It also swells when it gets wet., hehehe. So.... after the lumber yard has made it's rough cut... the wood gets sent to a kiln, where the moisture content is dropped to around 6% to 8%, here in the US. Then, it is planed, to get rid of those rough saw marks.... and you lose a little more off of the total size.

So, unless you buy 'green' lumber, it is going to be smaller than the size it is called.

I used to buy oak by the truckload, as a furniture manufacturing manager....and we went by "quarters", rather than inches.... a 4/4 board... what would be called a ' 1"x __' at the lumber yard... surface planed- hit/miss would be about 7/8" thick... but there would be some rough saw marks on it.....at the lumber yard... that same piece of lumber, would be only 3/4" thick, but it would be relatively smooth... no rough saw marks.

So, the "nominal" dimensions we use, to refer to the 'first cut' of the lumber... before it gets dried, and planed to a smooth surface.

Answer 2

Up to nominal 8 inch lumber the real dimension is a half inch smaller than the nominal size. Starting at 8 inches the real dimension is three quarters of an inch smaller. Why? I don't know but that is the way it is.

Of course there can be some tolerance in all real lumber dimensions depending on the setting of the planer or dryness of the wood. A sixteen of an inch plus or minus is not unusual so you could end up with two pieces with as much as an 1/8 difference in width.

Answer 3

I only recently learned this. A 2x4 you typically buy is not 2" x 4" because it's "finished" - the outer layer is removed.

The 2x4's in my old house, built at the turn of the (last) century, were really 2" x 4", but they had a rough-hewn surface. At some point, everything went to a finished surface, where the top surfaces were trimmed, and the actual cross section became 1.75" x 3.5".

Can't tell you what a 6 x 14 cross section becomes - but boy that's a huge piece! Maybe ask the lumber place that would actually supply it...? I don't know that they'd take off more wood just because it's a larger cross-section.

Answer 4

You got the 5.5 right, however after you go above a 6" (2x6) the dimension actually loses a full inch. 2x8's are really 1 1/2 x 7". 2x12's are really 1 1/2" by 11".

Answer 5

budgit cuts, all lumber is likr that. a 2x4 is the same way. That is what the old numbers used to be. instead of changing them they just left it. its weird I know but that is the way it is.