Get a Grip on Lumber GradesComments (0)
This article is from Issue 49 of Woodcraft Magazine.
Make the right wood choice for your next project.
Consultant: Larry Osborn
Whether buying hardwood or softwood, it helps to understand how boards are graded and sold so you know what to ask for when selecting stock, and, in some cases, to save money. For starters, the various hardwood grades stem from the appearance of a board and amount of clear wood; softwoods break down into structural and appearance grades, with the former having to do with the structural integrity of the board in the number, size, and location of the defects. Defects for both hardwood and softwood include knots and knotholes, bird pecks, sap pockets, pith, stain, decay, splits, checks, bark, wane, rot, and warp. Warp includes cup, twist, crook and bow.
A trained grader assigns a grade to a hardwood board at the sawmill shortly after the log is cut. Softwood grading happens after drying and surfacing the lumber. For both woods, the fewer the defects, the higher the grade and price. Use this guide to get a grip on grades.
If you don’t need the full width and length of a top grade clear board, drop a grade or two, work around the defects, and realize a better bang for your lumber-buying buck. For instance, you could opt for No. 1 Common instead of FAS for smaller parts in a project not needing wide and long boards or where appearance is a nonissue.
Hardwood boards destined for cabinet, furnituremaking, and woodworking in general are appearance graded based on their minimum yield of clear-face cuttings. As shown in Figure 1, clear cuttings are the rectangular defect-free sections of wood in a board. The best grades yield large clear areas with the fewest cuttings. At a sawmill that produces fine hardwood lumber (called a “grade mill”), you typically find five grades, all established in 1897 by the National Hardwood Lumber Association (NHLA). They are as follows:
- First & Seconds (FAS), the highest and priciest grade, represents boards from 6" and wider to 8' and longer. Graded from the poorer side, FAS boards will yield 831⁄3% to 100% clear wood in minimum-sized cuttings at least 3" wide and 7' long or 4" wide by 5' long (Figure 2). Architectural millwork and molding manufacturers favor FAS in order to obtain the long length pieces they need for their product. Furnituremakers favor it as well.
- FAS 1 Face (F1F), the second highest grade, amounts to practically the same as FAS except that both faces of the boards are graded, with the best face meeting FAS guidelines and the other face No. 1 Common. F1F also yields at least 831⁄3% clear face cuttings. F1F has the same uses as FAS.
- The next best grade, Selects, are essentially the same as F1F (and sometimes grouped with it and sold as “Selects and Better”) with a 4" × 6' minimum board size. Usage runs about the same as FAS.
- No. 1 Common boards (Figure 3) are 3" and wider, 4' and longer, yielding at least 662⁄3% clear face cuttings in minimum sizes of 4" × 2' and 3" × 3'. It’s graded from the poorest face.
- No. 2 Common boards, due to the generally smaller sized pieces obtained from them, allowable surface defects that detract from appearance, and a low minimum yield of 50% clear wood, are rarely utilized as woodworking stock. The grade does, however, meet the needs of flooring manufacturers.
How It's Sold
Should you shop for hardwood at the local home center, expect to find premium-priced, clear, S4S (surfaced four sides) boards in specific thicknesses, widths, and lengths. Also expect limited species (red oak, maple, yellow poplar, and perhaps walnut). Your other choices include buying from a sawmill, hardwood specialty store, or online supplier. There, you’ll typically pay less, buy by the board foot (1 × 12 × 12"), and encounter multiple species in random lengths and widths that are rough-sawn or S2S (surfaced two sides). Sawmills offer the best deals, selling rough-sawn (unsurfaced) lumber in several grades and thicknesses that include 4⁄4 (1"), 5⁄4 (11⁄4"), 6⁄4 (11⁄2"), and 8⁄4 (2"). Online dealers carry rough-sawn lumber (in plainsawn and quartersawn where appropriate) though they’ll sell S2S for a fee. Note that planed S2S boards will run 3⁄4-13⁄16", 1-11⁄8", 11⁄4-13⁄8", and 13⁄4" thick. You can also purchase thicker squares for table legs and turning stock. Hardwood specialty stores, such as the Woodcraft retail stores, sell top grade FAS boards that are S2S for best appearance and customer viewing. Note that figured woods do not abide by the standard grading rules and are priced according to the quality and desirability of the figure.
Softwood lumber often comes with a stamp that tells the grading association, sawmill number, grade, species (sometimes), moisture condition, and stress rating if any.
In contrast to hardwoods, softwood grading separates into construction or remanufacture (wood that is to be further machined and processed into other products, such as pine molding or furniture parts). Construction lumber (softwood’s primary use and of interest here) is what you find at lumberyards and home centers, and it’s what woodworkers and crafters look to for project wood. Typically available as S4S, it falls into the following three divisions:
Stress-graded–This lumber type (typically 2-by and thicker building material) emphasizes strength as the highest grading consideration and is either machine tested or visually graded for strength. Its visual appeal remains secondary, making the wood not exactly a woodworker’s first choice for other than utility projects.
Nonstress-graded–In addition to strength, appearance plays a level of importance in the higher grades of this softwood lumber category, making it of greater interest. The grade comes from the best side of a board based on the allowable size and number of defects (mostly knotholes as opposed to sound knots).
Grades drop as boards display larger and more numerous defects. These grades feature the familiar 3⁄4"-thick boards in nominal widths of 2"-12" in 2" increments and lengths from 6'-18' in 2' increments. They include the following:
- No. 1 (Construction). This wood, with its moderate-sized tight knots, works well for shelving, paneling, and some furniture. It paints easily.
- No. 2 (Standard). Containing more and larger knots, it too can perform like No. 1 grade, but doesn’t paint as well.
- No. 3 (Utility). Here, knots, knotholes, splits, and other defects limit the use of this lumber grade to pallets, crates, and other rough construction uses. It’s of little value to woodworkers.
Appearance-graded–Of highest woodworking interest, however, is what’s labeled as appearance-graded. This lumber emphasizes appearance, making it the best choice for cabinets and furniture, especially pieces slated for a natural finish. Included is wood found in casing, base trim, and paneling. It includes:
- Finish, the highest designation in appearance grade, further divides into designations that employ letters or combinations of letters (B&BTR, C, D). Depending on the grading agency, names such as Superior or Prime can be applied.
- Selects, next in line, include similar grade designations (B&BTR, C Select, D Select). That said, some specific softwood species, such as western red cedar, redwood, and Idaho white pine have their own designations, but much simpler. At a lumberyard, you’ll encounter only four grades of Select boards–A, B, C, and D with A being the highest. Grades A and B are rolled into one grade called B and better (B&BTR). Among Select grades, you’ll find:
- A Select. With no visible defects, this wood works well for cabinets, furniture, and trim.
- B Select. Having small, infrequent defects, use this grade for cabinets and furniture.
- C Select. While one side has tiny tight knots, the other may be near perfect. Use as above.
- D Select. This grade contains pin knots and numerous small blemishes. Use it as above to a lesser degree and for rustic pieces.
If your project doesn’t need to have both sides of the wood exposed to view, choose a lesser appearance grade with one good face, such as C Select over B&BTR for savings. With a softwood piece to be painted, you have even more money-wise leeway, but be sure to seal all knots before finishing!
How It’s Sold
At most big box stores and major retail lumberyards, the top softwood grades described above traditionally are priced by the lineal foot and standard dimension thickness of 3⁄4" and in 2" width increments (1×2, 1×4, and so on). Also keep in mind that common construction grades are surface dried (S-Dry) to 18-20% moisture content, while the more expensive, higher select grades of woodworking and furniture stock are kiln-dried (KD) from 8 to under 18%. Be sure to check the grade stamp for these designations. Also keep in mind that the longer the wood sits at the yard, the more likely the moisture content could rise, particularly during the rainy season.
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