[beckthompson]

You also have to remember that new 2x4s are actually 1.5x3.5 while older ones were actually 2x4! Its fun to do work on an old house and actually get the correct measurement of 2x4 xD

[dnemmers]

Original 2x4s were rough cut on all sides, after planing 1/4” smooth on each edge…you lose 1/2” from each dimension, resulting in a 3.5” x 1.5” board.