Three meanings of grain
Grain, texture and figure
- Grain (direction)
- The direction the wood's fibres run — 'along the grain', straight grain, spiral grain. The Wood Handbook calls this the preferred use of the word.
- Grain (texture)
- Used loosely for the size of the cells, as in fine or coarse grain. Finishers' 'open-grained' and 'close-grained' woods are the same idea: large pores that may need filling under a smooth finish, or small ones that do not.
- Figure
- The pattern on the surface: growth rings on a plainsawn face, ray fleck on a quartersawn one, and unusual growth such as birdseye, wavy grain and burls.
Because the words are used loosely, the Handbook advises agreeing on what 'open grained' or 'coarse textured' means before ordering by those terms. On this page, 'grain' alone means fibre direction.
Plainsawn and quartersawn
A board sawn tangentially to the growth rings is plainsawn (flatsawn) in hardwoods, flat-grained or slash-grained in softwoods; one sawn radially, out from the pith, is quartersawn in hardwoods and edge-grained or vertical-grained in softwoods. In commercial practice the Handbook defines them by ring angle at the board's end: 0° to 45° to the wide face is plainsawn, 45° to 90° quartersawn. Hardwood with rings at 30° to 60° is sometimes called bastard sawn. 'Rift sawn' is used in the trade for boards near the middle of that range, but the Handbook gives it no angle — only an oak-flooring separation of 75% rift character.
| Property | Plainsawn | Quartersawn |
|---|---|---|
| Movement | Shrinks and swells less in thickness | Shrinks and swells less in width |
| Distortion | More prone to cup | Cups, surface-checks and splits less in seasoning and in use |
| Figure | Growth-ring patterns shown more conspicuously | Ray fleck, interlocked and wavy grain shown more conspicuously |
| Knots | Round or oval knots; boards with them not as weak | Spike knots, cut along their length |
| Other | Less susceptible to collapse in drying; shakes and pitch pockets run through fewer boards; easier to obtain | Raised grain less pronounced; holds paint better and lets liquids through less readily in some species; sapwood only at the edges |
From the Wood Handbook's Table 3–1. The 'more prone to cup' row follows from its statement that quartersawn lumber cups less.
The width difference comes from shrinkage: wood shrinks about twice as much along the rings (tangentially) as across them (radially). In white oak, from green to ovendry, that is 10.5% against 5.6% (Table 4–3); a plainsawn board's width moves with the larger figure, a quartersawn board's with the smaller. The wood movement calculator takes the orientation and works out the difference for a given board.
Oak, ash, walnut, cherry: why they look different
| Wood | Pore pattern | What the face shows |
|---|---|---|
| Red and white oak | Ring-porous: large earlywood vessels, an abrupt change to latewood | Bold ring figure plainsawn; wide, tall rays give the fleck on quartersawn oak |
| White ash | Ring-porous | Bold ring figure; coarse texture where the earlywood pores are |
| Black walnut | Semi-ring-porous: between the two types | Medium texture |
| Maple, birch, yellow-poplar | Diffuse-porous: vessels similar through the ring | Even texture; ring figure is subtle |
Pore types and examples from the Wood Handbook, Chapter 3; the oak ray dimensions — more than eight cells wide and several centimetres high — are the Handbook's too. Black cherry is not classed in the passages reviewed.
That is why quartersawn oak is sought for its fleck while quartersawn maple looks much like plainsawn maple: the figure needs wide rays, which oak has. In woods with narrow rays, quartersawing changes how the board moves more than how it looks.
Grain direction and slope of grain
- Straight grain. The fibres run parallel to the board's long edge. Only a straight-grained log can give straight-grained boards.
- Diagonal grain. The fibres run out of the edge at an angle — the slope of grain. Such boards shrink and swell atypically and are weaker, depending on the slope.
- Spiral grain. The fibres wind around the trunk; no long straight-grained board can be cut from such a log.
- Interlocked grain. The spiral reverses direction every few years, so no board from the log is uniformly straight-grained; quartersawing brings the resulting figure out most.
- End grain. The cut ends of the fibres. It absorbs finish and glue differently from the faces; end-grain glue joints are covered in wood glue.
Reading the grain of a board
- Look at the end: rings across the width (plainsawn) or through the thickness (quartersawn)
- Sight along the edge for grain that runs out — diagonal grain
- On oak, look for ray fleck as the sign of quartersawn stock
- Note pores: coarse ring-porous wood may need filling under a smooth finish
- Choose quartersawn where width movement matters, as in wide panels
- Match grain across a glued panel for colour and figure
Grades, sizes and surfacing are in the lumber guide, and choosing boards for a project in choosing lumber.
Sources
Definitions are the Wood Handbook's. 'Rift sawn' is a trade term: the Handbook uses it only as an oak-flooring separation and gives no ring angle for it, so none is given here as a rule; ask the seller what their 'rift' means.
- 1.
Chapter 3: Structure and Function of Wood. USDA Forest Service, Forest Products Laboratory — Wood Handbook, FPL-GTR-282, 2021.
Used for: Grain as fibre direction (the preferred use), as texture, and the finisher's open and close grain; texture; plainsawn (rings 0–45° to the wide face), quartersawn (45–90°) and bastard sawn (30–60°) lumber, with the softwood terms flat-grained and edge- or vertical-grained; the advantages of each (Table 3–1); straight, diagonal, spiral and interlocked grain; ring-porous, semi-ring-porous and diffuse-porous hardwoods and their examples; wide, tall rays in oak; figure, including ray fleck.
- 2.
Chapter 4: Moisture Relations and Physical Properties of Wood. USDA Forest Service, Forest Products Laboratory — Wood Handbook, FPL-GTR-282, 2021.
Used for: Tangential shrinkage about twice radial; plainsawn width estimated from tangential and quartersawn from radial values (Table 4–3); distortion by ring orientation (Fig. 4–4).
- 3.
Chapter 6: Commercial Lumber, Round Timbers, and Ties. USDA Forest Service, Forest Products Laboratory — Wood Handbook, FPL-GTR-282, 2021.
Used for: Oak flooring separated by grain into plain sawn, quartersawn (50% quartered character), rift sawn (75% rift character) and quarter/rift — the Handbook's only use of 'rift', without a ring angle.
About this guide
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