Rule 15 of 31 · Chapter III — Read the Wood
Orient grain for strength and looks
Why this rule exists
Grain direction decides both how a part looks and how strong it is. A leg with grain running its length is strong; the same leg with grain running across it snaps under load. On show surfaces, matching or balancing grain across a panel turns a collection of boards into something that reads as one piece. Thinking about orientation before glue-up is the difference between furniture that looks composed and furniture that looks merely assembled.
In practice
Run grain lengthwise on legs, rails, and stretchers so the long fibers carry the load rather than shearing across it. For glued-up panels, arrange the boards so the grain and color flow naturally, and alternate growth-ring direction only if you're not flattening afterward. Lay the parts out and shuffle them for the best face before you commit any glue. Mark the final arrangement with a witness triangle across the joint so you reassemble it exactly the way you planned.
When it doesn't apply
Utility panels, drawer bottoms, and hidden structure don't need grain-matching, so prioritize using up your stock there. And plywood's cross-laminated layers make grain orientation a non-issue for strength, though you still mind the face veneer's direction for looks on show surfaces.