Berkeley CSUA MOTD:Entry 37343
Berkeley CSUA MOTD
2019/05/19 [General] UID:1000 Activity:popular

2005/4/25-26 [Uncategorized] UID:37343 Activity:nil
4/24    What is the historical reason that 2x4 studs are really 1 1/2 by
        3 1/2? Ditto with 2x2, 4x4, etc.
        \_ They're 2x4 rough, before they're sanded.
        \_ Ever been to a lumber mill? Its not really the sort of equipment
           that can give you more than 1/2 in accuracy.
          \_ actually, they are standard 1 1/2 x 3 1/2
                and btw- 2x4 is within 1/2 inch accuracy
        \_ Old 2x4 studs (like in my old house) are indeed 2x4.
           \_ How old is your house dim?
              \_ 1928
        \_ I heard it was because they use 2" of raw lumber to make 1 1/2"
           of finished lumber.
           \_ Sounds kinda like how the 19" CRT is really only 18". ;)
        \_ It was done by the lumber mills to cut costs and improve their
           profit margins.  They used to produce dimensioned lumber in the
           actual dimensions, but started undersizing so they could make
           more product from each tree.  Since their customers were already
           used to similar differences in sizing between rough and surfaced
           boards, it was pretty easy to get their customers to accept it.
           As for the poster who thinks that the equipment in lumber mills
           can't provide 1/2" of accuracy, you're way off.  You'll notice
           more variation in the dimensions of wood from it swelling and
           contracting as its moisture content changes with the humidity
           of the surrounding air than from variations in the milling process