Here is a story I tell from time to time.... My cousin's barn got hit with a hurricane back around 1950, hurricane hazel, I beleive. The hurricane ripped the roof off the barn, but the frame(including most of the rafters) stayed up and stayed square. We recently took that barn down and I was amazed to see that the mortise and tenon joints had 1/2" gaps inside. Very loose fit on the tenons but the shoulders were tight. Why did this barn not blow down? Could be good design/luck/ability to flex/great wood... but not tight joints. Seeing this frame changed my own attitude toward joinery, and I now wonder how crucial tight joints are to strength.
