# Wood Movement



## stephan (Feb 4, 2009)

After reading comments on my inquiry regarding joinery, I was reminded about another question. I have been reading books on furniture styles and several of the books talk mention that this or that is joined without gluing to allow for movement. I have thought about wood contraction/expansion as I have made things in the past but I never did anything about it because didn't know when it was needed. Nothing seems to have suffered for it, but I have not made anything very big. How do you know when to allow for movement?

thanks


----------



## dovetail_65 (Jan 22, 2008)

When attaching pieces across the grain of another. Like a piece of molding going across a solid panel.The panel will grow far more than the molding.

When attaching a very large piece to a piece that is much smaller in its area the large piece will move more than the smaller piece.

When attaching pieces with the grain running opposite directions.

When attaching a piece that changes direction in the Z axis, like adding legs to a table. "A wide, solid-wood kitchen table top can expand or contract up to 3/8" across its width. To deal with this, think of a table as two separate units -- a leg assembly and a top. If the top were fastened so it couldn't expand or contract, serious damage would result. If the top expanded, it could push the leg assembly apart. Or if it contracted, it could crack and split".

When making large glued up items.

Don't try to use glue to prevent expansion it will not work.

This list is no way complete at all. Entire books have been written on how to deal with expansion of wood.


----------



## xplorx4 (Dec 1, 2008)

Good question Stephen, I have heard that before, but never got around to asking. Nick thank you for the good answer. If and when I get done down stairs with all that needs to be done I can get started with some woodworking again.


----------

