Wood Grain and Bespoke Furniture: Part 2

Grain, Strength, and Movement in Solid Wood Furniture

Understanding what grain is at a cellular and structural level is only the starting point. The real significance of grain becomes apparent once timber is cut, assembled, and placed into service. Grain determines how wood carries load, how it responds to changes in humidity, and how it ultimately succeeds or fails as furniture.

For a bespoke furniture maker working in solid timber, grain directly governs the dimensions, proportions, joinery, and material choices used in a piece. Whether designing a record player stand or a walnut desk, the behaviour of wood over time must be anticipated rather than corrected after the fact.

This part focuses on how grain affects strength and movement, and why these two aspects cannot be separated.

Wood Is Strong Along the Grain and Weak Across It

One of the most important characteristics of wood is its directional strength. Wood fibres run predominantly along the length of the tree, and timber is correspondingly strongest in the longitudinal direction. Along the grain, wood performs remarkably well under tension and compression. Across the grain, its strength drops dramatically.

This anisotropic behaviour has direct consequences for furniture design. A long shelf in a record player cabinet gains its strength from fibres running continuously from one end to the other. If those fibres are interrupted, misaligned, or cut across, stiffness is reduced and deflection increases.

Similarly, desk rails, cabinet stretchers, and load-bearing legs rely on grain continuity for strength. Where grain is short or irregular, mechanical performance suffers regardless of how thick the component appears.

In solid wood construction therefore, visual thickness does not reliably correspond to strength; grain orientation and fibre continuity are far more significant.

Bending, Spans, and the Role of Grain Orientation

When a wooden component bends, the fibres on one face are placed in compression while those on the opposite face are placed in tension. Wood performs well under these conditions provided the fibres run uninterrupted along the length of the component.

In practical terms, this means that wide, flat boards used as shelves or tops should be oriented so that their grain runs parallel to the span. Cross-grain construction in load-bearing parts is one of the most common causes of long-term failure in poorly designed furniture.

In bespoke record player stands and vinyl storage units, this becomes particularly important. Shelves may carry significant point loads from turntables, amplifiers, or collections of records. Grain orientation, thickness, and support spacing must all be considered together.

Shrinkage and Movement: Radial vs Tangential Behaviour

As outlined in Part 1, wood moves as its moisture content changes. This movement is not uniform. Shrinkage and expansion occur primarily across the grain, and they differ between the radial and tangential directions.

Tangential movement, which follows the curvature of the growth rings, is generally greater than radial movement, which runs perpendicular to the rings. This difference is the reason boards tend to cup rather than shrink evenly.

Diagram showing impact of differential between radial and tangential shrinkage and how it causes cupping [1]

For furniture, this behaviour has profound implications. A wide, flat-sawn board will move more across its width than a quarter-sawn board of the same species. This does not make one inherently better than the other, but it does affect how each should be used. For example, when making drawers with tight fitting components where undue movement could cause the drawers to stick, quarter-sawn in definitely the way to go, although it does cost more.

In cabinet sides, door panels, and desk tops, this movement must be allowed for through considered joinery and fixing methods. Attempting to restrain it rigidly leads to splits, joint failure, or distortion.

Seasonal Movement Is Not a Defect but Must be Accounted for in Bespoke Furniture Design

Seasonal movement is often described as a problem to be eliminated. In reality, it is an inherent property of solid wood. The aim of good design is not to prevent movement, but to accommodate it predictably.

Furniture that survives decades of use does so because its construction allows wood to expand and contract without inducing damaging stresses. This is achieved through careful grain alignment, floating panels, sliding joints, and fixings that permit controlled movement.

Sliding dovetail joinery in one of my bespoke record player stands allows the wood to expand and contract whilst still maintaining the structural integrity of the whole

In centrally heated homes, relative humidity can vary significantly between seasons. Timber acclimatised in a workshop will almost always experience a change when moved into its final environment. Designing furniture that tolerates this transition is one of the defining skills of a competent bespoke furniture maker.

Reaction Wood: Compression and Tension Effects

Not all wood within a tree grows under ideal conditions. Trees respond to mechanical stress, such as leaning or wind exposure, by producing reaction wood.

Trees respond to asymmetric loading by producing reaction wood, but the form this takes depends on the species. In softwoods, reaction wood appears as compression wood formed on the lower side of leaning stems or branches. In hardwoods, it takes the form of tension wood, produced on the upper side. Both differ markedly from normal wood in structure, shrinkage behaviour, and mechanical properties.

Showing difference between compression and tension wood [2]

Reaction wood can be visually subtle but mechanically problematic. It often exhibits excessive longitudinal shrinkage, increased internal stress, and unpredictable movement. When released during machining, these stresses can cause components to twist or bow dramatically.

For bespoke furniture, reaction wood is generally avoided in structural parts. Where it is present, it must be understood and managed carefully. Ignoring it can result in furniture that moves excessively or distorts after completion.

Grain Irregularities and Structural Consequences

Grain is rarely perfectly straight. Deviations such as spiral grain, interlocked grain, and localised fibre distortion are common. These features contribute to visual interest but also influence strength and stability.

Interlocked grain, for example, can reduce the tendency for boards to split, but it can also increase movement and complicate machining. Spiral grain may introduce torsional stresses that become apparent only after material is cut to size.

Showing impact of spiral grain [3]

In furniture components subjected to load or restraint, such irregularities must be accounted for. A visually dramatic board may be entirely unsuitable for a long shelf or structural rail, but ideal for a non-load-bearing panel.

Grain Selection as a Design Decision

At this point, it should be clear that grain selection is not a cosmetic afterthought. It is a design decision with structural consequences. The placement of boards within a piece of furniture is as important as their species or finish.

In a record player cabinet, for example, grain direction in shelves, sides, and backs must be coordinated so that movement occurs in compatible directions. In a walnut desk, the orientation of the top relative to the base and its fixings determines how stresses are distributed as humidity changes.

Custom wood furniture succeeds when grain is treated as an active participant in the design rather than a passive surface.

Anticipating Behaviour Rather Than Correcting It

One of the defining differences between bespoke furniture and mass-produced alternatives lies in this anticipatory approach. Board-based furniture relies on engineered stability and surface finishes to suppress movement. Solid wood furniture relies on understanding and accommodating it.

This requires time, experience, and an acceptance that wood is never inert. When done well, the result is furniture that remains stable, functional, and visually coherent over long periods, despite seasonal change. For all the reasons why I prefer working with solid wood read this dedicated blog post here.

The goal is not perfection in the short term, but reliability in the long term.

[1] [Author Unknown] (n.d.) The three anatomical directions of wood: radial (R), tangential (T) and longitudinal (L) in ResearchGate [figure]. Available at: https://www.researchgate.net/figure/a-The-three-anatomical-directions-of-wood-radial-R-perpendicular-to-the-growth_fig1_371708288 (Accessed: 15 September 2025).

[2] MajorDifferences (2015) Difference between compression wood and tension wood [online]. Available at: https://www.majordifferences.com/2015/03/difference-between-compression-wood-and.html (Accessed: 15 September 2025).

[3] Galbert, P. (2024) Understanding wood grain [online]. FineWoodworking.com. Available at: https://www.finewoodworking.com/2024/02/16/understanding-wood-grain?srsltid=AfmBOoomG-Sm_mBTEEHAzl-JppJj6KTTqNtS2PYFBxlLBsGxw8K24DzL (Accessed: 15 September 2025).