To help guide our customers in their furniture choices – and unveil the art of furniture-making — we are proud to offer a blog series on the topic of wood grain and figure.
First off, what are we even talking about? Grain is a few things. It is the arrangement of cells in wood. This arrangement forms the annual rings seen in a cut log, creating the alternating pattern of light and dark that makes each ring distinctive.
When you look at a piece of cut wood, the details of the surface are called the “figure.” Notice how natural wood isn’t just plain brown, it has many features, like the distinctive light and dark pattern from the grain. There may be unique patterns in the grain, or other features that aren’t from the grain at all, but something else entirely. Much of the visual landscape you see in a piece of wood is from the grain, but figure may be affected by much more than just the grain. The culmination of all of these features is what a furniture maker means when he or she says “figure.” Figure is a major determinate of the beauty of your furniture.
The grain and figure of the wood are critical factors in how it looks, how much it costs, how easy it is to work with, and a whole lot more. There is a lot to grain and figure, and your furniture maker will help you through the process, but this series will arm you with the information you need to make a choice, and may even give you some ideas for future furniture.
At The Sawmill
The sawmill is the first stop at which decisions are made that affect the grain and figure of wood. The big decision? How one cuts the log into boards. A piece of wood is like a steak, the cut makes the difference between the good, the bad, and the ugly.
The most basic aspect of cutting a board from a log is that a log is round and a board is not. Circular patterned wood needs to be cut into a straight board. It’s one of those things that’s almost so simple that it can be easily overlooked. The difference between the circular rings and the straight board is probably the most fundamental aspect of how a piece of wood ultimately looks.
Notice how the grain in this piece of wood runs pretty straight horizontally. To get a straight grain from round rings, the wood must be cut perpendicular to the direction of the rings.
There are three primary methods for cutting a log:
Flat-Sawing: When a log is cut into boards, generally from top to bottom. It is the most common way to cut a log, the fastest way to cut a log, and results in the least amount of wasted wood.
Notice how the angle of the rings is different for each cut
Guild member David Hurwitz explains that using the flat-sawing method on hardwoods results in “cathedral” shaped arches in the grain, because the cut occurs at angles against the circular grain. The different parts of the wood dry and swell unevenly, so the most stable cuts of wood come from lumber cut perpendicular to the grain, which makes the features as even as possible. As a result flat-sawn lumber is more prone to warping and coming apart when being worked for the same reason it bears a cathedral figure, because the cuts aren’t perpendicular to the grain.
Compare to the straight grain picture above. This grain is more angular and then turns back the way it came.
Rift-Sawing: Rift-sawing a log means that every board is cut perpendicular to the grain. This typically creates the straightest possible grain on each board. As a result, these pieces are also usually the most stable and are less likely to come apart when being worked. They may also resist warping and shrinking more than non-perpendicular cuts. Rift-sawing is, however, the rarest method, as it results in a lot of wasted wood, which also makes it more expensive.
Every cut is perpendicular to the grain, yielding a straight grain
Quarter-Sawing: This is a happy medium between flat-sawing and rift-sawing. Some of the center cuts of wood will be perpendicular to the grain as in rift-sawing, but as the boards move away from the center, the grain becomes progressively skewed. This method provides a good mix of efficiency, speed, and high-quality wood with good figure.
Hurwitz explains that there’s a specific type of figure that may result from quarter- or rift-sawn wood that isn’t the result of the grain itself. Specifically, this figure comes from the “medullary rays,” a feature of some woods like oak and sycamore. In the living tree, the medullary rays are a transport system that moves through the rings, perpendicular to the grain, and so are readily visible in cuts that are also perpendicular to the grain. This figure is striking, and can be quite beautiful.
“Ray flecks” from medullary rays running vertically. The grain runs horizontally and is straight. Note the difference in beauty compared to the picture above with only straight grain. This piece of wood would be called “highly figured” because of how much character it has.
Here’s a great video that shows how the quarter-sawing works, and how the medullary rays show up in some boards and not others. (Note: Don’t be confused with his use of the term “rift lumber,” he means something different from “rift-sawing” mentioned above.)
Drying the Wood
Besides cutting the wood, a sawmill will generally dry the wood as well, which may further affect figure and workability, but not usually as significantly as the process of cutting it. Specifically, the drying process (which can be done naturally, or in a kiln) reduces the moisture content of the wood. This helps to stabilize flat-sawn cuts, and can thus make wood more workable for the furniture maker.
The drying process can also produce a unique type of figure called “spalting.” Spalting, which will be described more in-depth in a later blog entry, is a figure that results from a fungus infecting the wood. Hurwitz explains that the kiln drying process kills the fungus and thus leaves the wood with a unique figure while preventing the rotting process, keeping your furniture intact and highly unique.
The wood is worked first by the people operating the sawmill, and as you can see, the choices made there will have a big effect on the look and cost of your furniture. Cutting a tree perpendicular to the grain, gives a straight-grained figure, makes the wood more stable, and takes more time to cut while resulting in more waste (although Vermont-sourced lumber is a sustainable practice, by law).
For heirloom furniture, opting for strong, quality lumber is critical, and depends hugely on how it is cut and dried, and your furniture maker will need a high quality cut of wood if it is to be carved or bent. When it comes to the figure, seeing the cathedral helps you tell how the piece was cut (at an angle to the grain), and if you want the cross-hatch look of the medullary rays, which can be quite beautiful, a nice perpendicular cut is what your furniture maker will choose.