Thread: Beginner question on wood expansion

I believe at that size you would be hard pressed to measure expansion but in any case the base is never going to be an absolute tight fit. The options i would suggest are,

Cut the base 1-2mm short either way and let it float.
As i do when making boxes, apply a spot or two of glue at each end just to stop it rattling around.
Use a nice veneered ply 4mm or 6mm thick and expansion will not out of the equation.

Is there an issue with letting it float?
Thats the easiest way to allow for expansion. Gloing a side or middle of both ends also works but letting it float has been my go to for solid wood bottoms.

You can generally find the movement numbers on google. Ie wood database.

Originally Posted by double.d

I believe at that size you would be hard pressed to measure expansion

Agreed, not worth worrying about.

Ahhh, good - thanks! The dovetails have taken a while, so I'd hate to think they'll blow apart with a solid base! thanks for putting my mind at ease!

While it may be difficult to measure the expansion, rest assured that if you don't allow for it, it can pop joints. As said, allow ~1-2 mm, and use a spot of glue in the middle of each end. There's no structural issue with leaving the panel floating, but it may be annoying.

Main problem with leaving it floating is that I you may get an unsightly line around the edge of the base as it exposes timber which was previously hidden. You can mitigate this somewhat by prefinishing the base before you embed it, but that makes gluing it challenging. Well hidden metal fixings where you were planning to put glue might be ok - headless pins maybe.

Forgot to mention. We used to be able to buy foam balls that you put in the grooves to control the movement so the base was always centred and didn’t rattle. I haven’t seen them for sale lately but there should be plenty of diy substitués.