Quarter-sawing is a method of milling trees into lumber. Quarter-sawn lumber is highly sought after, particularly in certain species such as oak or maple, where look of the grain in the wood is accentuated by the method of cutting the tree. While rip-sawing is the most efficient (and common) method of milling, quarter-sawing is more difficult to cut but yields much more stable lumber. Because it is more difficult to cut and there is more waste, quarter-sawn lumber is considerably more expensive than rip-sawn material.
Why Quarter-Saw Lumber?:
Quarter-sawn lumber is more stable, because it is cut in a manner that attempts to get as much of the end grain of the wood perpendicular to the face of the board as possible. Without having grain running parallel to the face of the board, there is far less chance of the board twisting or cupping as it dries, or worse, when in use in a project. The more square the end grain is to the face of the board, the more stable that board will likely be over the course of its life in the project.
Additionally, quarter-sawn lumber of a variety of species has a look that is unmatched by a rip-sawn board. Oak is a prime example: the grain of oak is much more wavy and displays medullary ray flecks that are far more unlikely to be visible if the board is rip-sawn. Because of these qualities, quarter-sawn oak was the primary type of wood used to create authentic Arts and Crafts era pieces of furniture.
How is a Tree Quarter-Sawn?:
There are a few methods of quarter-sawing a tree, but the most common is for the mill to cut the round tree into four quarters along the long axis of the tree, much like four 90-degree wedges of pie. These wedges are then placed with the center point facing upwards, and boards are ripped off of the wedge. As you might expect, the widest board will be from the center of the wedge, with very narrow boards from the edges. By cutting the tree in this manner, the growth rings (which form the grain of the wood) are going to be closer to square to the face of the board than on most of the boards from a rip-sawn tree.
How Does Quarter-Sawn Lumber Move?:
Properly quarter-sawn lumber will certainly move, just like all other cuts, based on fluctuations in humidity in the environment that the board is used. However, by cutting with the grain square to the face of the board, a quarter-sawn board will swell primarily across the face (making the board wider), whereas a rip-sawn board may grow in width and height (and very likely will twist or cup as it swells). Knowing how the wood will adjust to moisture changes should be considered when laying out the boards for your project.