Types of Lumber/ How to Tell

Lets review the types of lumber, flat sawn, riftsawn, and quartersawn. What do the names mean, and how do you tell them apart, and why should you care?

The key to telling the difference is “reading” the end of the board. What you’re looking for is the angle of the growth rings. This angle is determined by how the lumber was cut from the log.
(Copyright woodsmith magazine below)
“FLATSAWN. On flatsawn lumber, the rings will be 30 degrees (or less) to the face of the board. In many cases, especially with boards coming from large diameter logs, the rings will be parallel to the face. "

“Flatsawn lumber is the most common type of lumber you’ll come across because a log yields the most lumber when it’s cut this way. Because of this, it’s the least expensive cut available.”

“But flatsawn lumber tends to move a lot with changes in humidity — it often cups or warps. And the grain swirls in many directions over the face of the board. When this wild-grained wood is stained, the softer more porous early wood will soak up more stain and look darker than the harder, less porous late wood.”

“Lets look at riftsawn lumber. When I’m looking for more attractive boards than flatsawn, I look for riftsawn.”

“In this case, the growth rings (in the end grain) are greater than 30 degrees, but less than 60 degrees to the face of the board. Riftsawn lumber generally has straighter, clearer grain than flatsawn lumber. "

“Usually riftsawn lumber is mixed right in the same stack as the flatsawn. In fact, many boards in a flatsawn stack will have both riftsawn and flatsawn grain. When a single board has both types of grain, what you actually see on the face of the board is wild grain running alongside nearly straight, clear grain.”

“Another reason to look for riftsawn wood is for its stability — it’s more dimensionally stable and less likely to warp or cup than flatsawn lumber.”

“A look at quartersawn: top ’o the line. The straightest grain comes from logs that are quartersawn. Here, the growth rings will be 60 degrees to 90 degrees to the face of the board.”

“In addition to really straight grain, some hardwoods, such as red and white oak, cherry, and hard maple, exhibit highly figured grain (ray flecks) when quartersawn. And when finished, these woods can be quite striking.”

“Also, when the humidity does change, quartersawn lumber is the most stable of the three cuts of lumber. The downside to quartersawn lumber is that it requires larger logs to produce reasonably wide boards. And since there’s more waste (a lot more), it’s the most expensive cut.”

“So buy the cut you need. If you’re building reproduction Arts and Crafts furniture, then quartersawn lumber is the only way to go. But most of the time, it will be worth your trouble to spend the extra time searching through the pile of flatsawn lumber to pull out the riftsawn boards.”
(End of copyright )