Buying Cabinet-Quality Lumber
The wood used for furniture and other fine projects differs in many ways from lumberyard 2x4s.
The first thing to realize about cabinet-quality lumber is that the rules you probably know about ordering dimension lumber (the type you use for carpentry work) don't apply. Sizing, grading, ordering -- they're all different. Also keep in mind that except for a few white pines, redwood, and cedar, most of the time you'll be working with hardwoods.
Understanding Moisture Content All cabinet-grade lumber begins as a "green" board that's been mill-sawed from a freshly felled tree. The moisture content of a green board will be 28 percent or greater, making it unsuitable for woodworking because all wood shrinks, warps, and splits as it dries.
Air-drying reduces the moisture content naturally -- workers stack the slabs in such a way that air circulates between the separated layers of boards. Air-drying lowers the moisture level to between 12 and 17 percent. (This is acceptable for outdoor construction, but don't make any interior projects using air-dried material.)
Kiln-drying takes over where air-drying leaves off. Large oven-like kilns with carefully controlled temperatures reduce the moisture content to between 6 and 9 percent, the ideal range for interior projects.
With few exceptions, retail hardwood dealers sell only kiln-dried lumber. It's stored and sold indoors under a roof where the elements won't affect it.
When you purchase kiln-dried lumber, store it indoors lying flat on dry sticks of scrap or hardboard. Never lay it directly on concrete because it will absorb excess moisture.
How Hardwood Lumber Is Sized Unlike dimension lumber, which is milled to industry-established nominal thicknesses, widths, and lengths, most cabinet-quality stock comes in random widths and lengths to keep waste to an absolute minimum. In addition, because all furniture and other woodworking projects have different dimensions, there's no need for dimensioned stock.
Thickness, though, has been standardized, and is expressed in different ways, such as 4/4 (1"), 5/4 (1 1/4"), 6/4 (1 1/2"), and so on. Don't be confused by all this; just remember that the quarter designation and the nominal thickness are the same animal.
When you order cabinet-quality lumber, you'll receive a board as long as or longer than and as wide as or wider than the item ordered. The thickness (if surfaced) will be close to that listed in the chart. When you purchase hardwood lumber, you buy it by the board foot. Even if the dealer has the boards already priced, he arrived at those prices by first figuring the number of board feet each contained.
A board foot, simply, equals 144 cubic inches of wood. Think of it as a piece 1 inch thick and 12 inches square. Because board footage always is calculated in quarters of an inch thickness, starting at no less than 1 inch (even if you order less than 1 inch, you'll pay for the 1-inch thickness), a 5/4 board 6 inches wide and 72 inches long would be figured like this: 1.25 (thickness) x 6 (width) x 72 (length) = 540. Divide 540 by 144 to determine the number of board feet in the stock. If the board length is stated in feet rather than inches, use the same method but divide your total by 12 instead of 144.
How Cabinet-Quality Lumber Is Graded Unlike dimension lumber, which manufacturers grade according to its use in construction as full width and length members, hardwood is graded according to the expected number of clear face cuts a board will yield. And, because most hardwood is expected to be made into furniture, these cuts will be from 2 to 7 feet long. For more information on the hardwood grading system, which was developed by the National Hardwood Lumber Association, see the chart below. This same chart also discusses the grading system for white pine, which was formulated by the Western Wood Products Association. In cabinet lumber there are great differences in quality, just as there are in construction lumber, so use the chart as a guide.
Remember, too, that in building a large project, such as a table or desk top, you'll generally need the higher grades of lumber because they have fewer defects and are available in greater widths and lengths than lower-grade boards of the same species. Many retail hardwood dealers carry only the highest grades possible to avoid customer complaints and discount requests.
Estimating Your Needs Before you purchase any lumber for a project, draw or refer to a published cutting diagram, and figure the board footage needed. And, if at all possible, buy from a dealer who will allow you to hand-select your boards.
Hand-selecting gives you two distinct advantages. First, you can choose the grain, color, and texture you'd like to have. Second, you'll be able to select your lumber in sizes that accommodate your cutting list and thus reduce waste. If you cannot choose your own lumber, allow about 20 percent for waste, and add it to your needed board footage.
Where to Buy Cabinet-Quality Lumber In addition to the cabinet-quality lumber available from lumberyards, home centers, and retail specialty stores, you have the option of mail-order buying. Though you'll be able to order pieces down to 1/4" in thickness, lengths normally wil be limited to about 6', because shipping is done via UPS or parcel post.