The finished size of the "2X4" is more complicated than Gurney told us.

Up until World War I, the finished size of the "2x4" was in fact--you guessed it!--two by four inches. As a wartime economic restraint matter, its official size was reduced by some fraction of an inch, and the size was not restored when the lean times were over.

Then in the middle of the 20th Century--I think I remember it as being some time in the 50s-- the official size was reduced again, to its present size. I recall when it happened, but not just when it happened. I'm not sure what the argument was to the Standards Bureau at that time.

Dave Oesterreich