I am not sure how to quote someone on the forum, so here goes.
Dave Monk. The wall thickness is 3/4" Red Oak. Including the top and bottom, 1 1/4".
Kevin. This is a standard Diana Thompson box. A lid liner is cut on the inside and glued to the lid. The perimeter glueup is then cut. The inside of the lid liner fits the box wall nicely.
Thanks for all the nice comments.