gizmoman

I build chairs and repair older chairs too. I would like to suggest that the reason George Nakashima made a saw cut on the top of each tenon was not only to make a tight fit but to maintain the integrity of the glue joint even through stressful humidity changes. The glue joint around the perimeter of the tenon can remain intact while the center cut opens up slightly. There was probably no glue or wedge in that center cut and since Mr. Nakashima knew this technique he probably also oriented the leg grain for the least movement as well. A real craftsman. There is mention of this technique in Bruce Hoadley's Understanding Wood book, I believe.