Woodworking
Working with a material that keeps moving.
Woodworking shapes and joins wood. The defining difficulty is that wood is not dimensionally stable: it absorbs and releases moisture with humidity and changes size as it does, for the whole life of the piece. Nearly every traditional technique exists to accommodate that.
Grain and movement
Wood moves very little along the grain, noticeably across it, and most of all tangentially — roughly twice the radial figure. A wide tabletop can change width by several millimetres between seasons while its length stays effectively fixed. Fastening a wide panel rigidly at both edges will split it; the panel must be allowed to float.
Hardwood and softwood
The terms are botanical, not descriptive. Hardwoods come from broadleaved deciduous trees, softwoods from conifers. Balsa is a hardwood and is softer than most softwoods, and yew is a softwood harder than many hardwoods.
Joints
| Joint | Used for | Strength |
|---|---|---|
| Butt | Quick work, reinforced with screws or dowels | Weak alone |
| Mortise and tenon | Frames, chairs, doors | Very strong |
| Dovetail | Drawer and box corners | Strong; resists pulling apart |
| Lap | Crossing members | Moderate, easy to cut |
| Housing (dado) | Shelves into uprights | Good in one direction |
Well-cut joints resist racking through geometry, so the glue holds parts together rather than doing the structural work. Glue is stronger than the wood on long grain and weak on end grain, which is why end-grain butt joints fail.