I like it! What precautions have you taken against expansion?
Great question! I find that if you use two lag screws that are six to eight inches apart, then expansion isn't an issue. The table pictured above is a bit of an illusion because there are no lag screws near the edge of the table, just behind the center two dowels. Here is another example that shows what I mean: http://3.bp.blogspot.com/-DJ9mYt3tsS8/Uc8megRhyWI/AAAAAAAABDw/Lqqc2zP_ktU/s1600/_MG_4865.JPG