Alright guys, I don't even know why I bother answering any more but this will make since to all of you when I explain it. Wood expands and contacts with the level of humidity in the air...OK. Now, put the slates all together, level them up....don't glue the slates together to keep the seams LOOKED to each side.....the FRAME grows in length, and shrinks in length with expansion and contraction....got it? Now, when the frame contracts, shrinks...the frame pulls the slates together at the seam....squeezing the wax up out of the seam, and for all you that suggests bondo is the answer to stop this action from happening....you're wrong...Rob....the slates will still move unless they're LOOKED together, proof of that is when you take the table apart, pull the slates apart....and notice that nice little 1/4" wide piece of slate seam that broke away from the sharp 90 degree edges on both sides of the seam....leaving you that nice little ditch at the seam that requires more bondo to fill it in the next time it's assembled.....CLASS OVER.