A problem that can’t be denied—wood moves!
No matter what you do, the wood in your projects is going to move as the seasons change. I learned the hard way like most woodworkers when I watched one of my beautifully constructed pieces of furniture split. The joint was almost seamless right up until the humidity changed, and it split right down the middle. I knew about wood movement. I had read about it in nearly every article or project plan I had ever looked at. I just thought they were making a bigger deal out of this little wood movement issue. Over the past five years of building projects I’ve begun to understand just how big of an issue it is. You MUST account for wood movement regardless of the size of the project. As humidity changes the cells in the wood swell or shrink. The worst part–it does it randomly depending on the wood, the amount of humidity and probably a million other factors beyond the scope of this blog. The one thing you can count on is that generally the movement occurs across the grain. Also plywood is pretty stable because of the way it is put together with alternating grains with each ply so there is a less of a concern about wood movement.
The bottom line—you can’t stop it from happening so you must account for it. There are a few things you can to do to preserve your project. First, let the wood acclimate for several days in the shop before you start building. When you are constructing a piece, never trap the wood so it can’t move and whenever possible avoid cross grain assembly. This means using fastening methods that allow the wood to move and don’t glue in pieces that need to float in a project. If wood movement is dealt with properly, your project will last much longer. Hopefully you’re reading this before you learn the hard way.