What a year of seasons does to a chair

A hardwood chair in a heated flat is not a stable object. It takes on moisture through a damp summer and gives it back through a dry winter, and across the width of a 70 mm rail that is a movement of a few tenths of a millimetre either way. Along its length it barely moves at all.

That difference is what kills screwed joints. Steel does not move. The wood around the thread does, and each cycle the thread gets a little less to hold onto. Eighteen months later the chair has a wobble, you tighten the screw, and you have made the hole slightly worse.

An oak peg in an oak joint moves at the same rate as everything touching it. There is no differential, so there is nothing to work loose. The joint you pegged in July is the same joint in February.

What we do ask of you

Keep it off a radiator and out of a sunbeam. Neither will pull a joint apart, but both will move one face of a board much faster than the other, and that shows up as a cupped seat long before it shows up as a loose frame.