Reply To: Trestle table top
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By all means arrange the boards so that any rising grain is all facing the same way; however, what I infer from your question is the fact that some of the boards may ‘cup’ or warp as they acclimatise. This will certainly happen if you change the board’s environment – nothing to be done about this other than let it happen, let it all reach equilibrium and then flatten both sides again. It’s what wood does. Cupping occurs because the heart-side of the board dries slower than the bark side.
One accepted strategy, where a series of boards are arranged edge to edge, is to minimise movement (and any subsequent remedial planing) by aligning the boards in an alternating sequence; heart-side uppermost, then bark-side, then heart-side and so on. This means that even if the top is very slightly corrugated, any cupping cancels itself out across the width. In reality, a cupping of only a couple of millimetres across a 4 inch board is not worth bothering about.
Where boards are edged for a table, I note that you have boards almost 8 ” wide – I would strongly advocate keeping them about 4” – 5” wide – in order to minimise cupping and to assemble the whole thing without glues – especially if it is outdoors. 7-plus inches will give a deeper cup than 4 inches. Ideally Tongued and Groved (or grove and spline) with bread-board ends, fixed with draw-bored pegs. This method may minimise movement, but allow the whole thing to move with the change in seasons and will leave the possibility that if the worst comes to the worst, (it warps badly) you can take the whole thing apart and re-make it.
Here’s a couple of photos of a table top of similar dimensions to yours that I made about 10 years ago using T&G, bread-board ends and draw-bored pegs which illustrates the method I outlined.
Good luck