Wood Moves Across the Grain and Barely Along It — and It Never Stops

A board gets wider and narrower with the seasons and stays almost exactly the same length. That one asymmetry explains nearly every piece of furniture that has split itself apart. The numbers are not small. A 300 mm oak board can move 6 mm or more across its width between a damp summer and a heated winter — and along its length, over the same 300 mm, it moves about a tenth of a millimetre. Nothing stops it. Wood is hygroscopic for as long as it exists: finish slows the exchange but does not prevent it, and a 200-year-old table still moves every year. So the craft is not preventing movement but DESIGNING FOR it — which is what the rest of this batch is about.