All Inclusive Guide to Wood Classifications and Species (Part 2)

Different Cuts and Designations of Lumber

Plain sawn, rift sawn and quarter sawn: what is the difference and what does it all mean? To a sawyer who mills logs these definitions may mean how a particular log is cut into lumber. To a furniture maker, woodworker or consumer these definitions explain details about the particular piece of lumber itself regardless of how the sawyer milled the rest of the log. Simply put these definitions describe the orientation of the lumber when it was milled from the log. The easiest way to see this orientation in most lumber is to look at the end grain of the wood to view the growth rings. Plain sawn lumber will have growth rings up to 30 Degrees to the face of the board. Rift sawn lumber will have growth rings 30 to 60 Degrees to the face of the board. Quarter sawn lumber will have growth rings 60 to 90 degrees.

The purpose of having this knowledge isn’t to be able to look at a board and determine if it’s quarter or rift sawn. More often than not, unless you intentionally purchase lumber which was labeled one of the three then it will be a combination of them all. The knowledge to take away is that based on the orientation of the growth rings, lumber will present a different look, on it’s faces and edges, and behave differently in regards to wood movement. See the illustration for examples of each according to its end grain and face/edges. Generally, the closer the growth rings become to 90 degrees to the face the more stable the board becomes at resisting unwanted wood movement such as cupping.

Measuring Lumber

Another designation you will see when purchasing, working with, or speaking about rough sawn lumber is its thickness. You may wonder how measuring thickness can be so complicated. Well we enjoy sounding cool when we talk about lumber, so we made up new system! I’m sure there is lots of history behind this, but I like my reasoning for now. Anyway, everything is measured in quarters of an inch. 4/4 (pronounced: four quarters) equals 1 inch, 8/4 (pronounced: eight quarters) equals 2 inches and so forth. Most commonly lumber is milled into 4/4, 8/4, and 12/4, but this may change depending on your location and region; you may be able to find 6/4 or 10/4. These measurements are more of an average as a 4/4 may measure between 7/8”-1 1/8”. It is important to note that this is still rough lumber and after milling the pieces you will be lucky to get a 7/8” final board thickness from a (full 1”) 4/4 thick rough sawn board, more often you will be left with a 3/4” thick milled board instead.

Figured Lumber

Along with everything we’ve discussed some lumber may also be described using special designations to point out different qualities of particular pieces of lumber. Examples of these include: Birds’ Eye, Curly, Spalted, Figured, Live Edge, and Burl. Birds’ Eye can occur within several species of wood but is most famous in hard maple, forming tiny swirling “eyes” which break up the otherwise smooth grain lines. Curly lumber is very distinct and is almost an optical illusion as it appears to have waves flowing across the board perpendicular to the grain. Spalted lumber is caused by fungus, usually in dead trees, which causes changes in the lumber’s coloration. Figured lumber is a very broad term which simply means a particular board has certain characteristics which make it stand out. Birds’ Eye, Curly and Spalting are all examples of being Figured, however a particular board may be described as Figured solely from unique coloring and grain patterns. Live Edge lumber is simply when a board has kept its natural edge from the outer diameter of the tree. A Burl is generally an abnormality, as a growth or nodule on the side of a tree. Although creating a unique design, its maze of a grain pattern makes it very difficult to work with.

Stay tuned for the rest of the series!