Track 2
How wood behaves as a material. The most important track for avoiding mistakes — covers why boards warp, cup, twist, and shrink.
10 guides in this track
Moisture content (MC) is the percentage measure of water in wood, and it’s the starting point for predicting movement, acclimation, and drying decisions.
Equilibrium moisture content (EMC) is the moisture level wood naturally settles at for a given temperature and relative humidity, and it’s the key to seasonal movement and acclimatisation.
Wood movement is the predictable swelling and shrinkage of wood as moisture content changes, and understanding direction (tangential/radial/longitudinal) lets you design joints and panels that survive seasons.
Tangential vs radial is the single most useful cut-angle concept in timber: it tells you how much a board will move across its width for the same moisture change.
Longitudinal Movement (and Why It's Small)
Longitudinal movement is the small (usually negligible) change in wood’s length with moisture, and understanding the exceptions (juvenile and reaction wood) prevents “mystery” bowing and twist.
In the previous guides, we covered the three axes of wood movement — tangential, radial, and longitudinal — and the reasons behind each. Now it's time to bring them together.
Humidity (relative humidity, RH) is the real control dial for wood: it sets EMC, which drives moisture content change and therefore movement.
Case Hardening and Drying Stress
A board can be meter dry and still spring, pinch, or bow the moment you rip it. This guide is the moisture gradient behind that stress, how to spot it, and what to do before you machine.
Internal stress is why boards move after you cut them—sometimes from drying (case hardening), sometimes from growth stresses locked in while the tree was alive.
Some timbers barely move. Others fight you every step. This guide is what that difference is, what controls it, and how to choose species, cut, and construction so the movement does not wreck the work.