:max_bytes(150000):strip_icc()/stack-of-old-wooden-railway-sleepers-background-pattern-533048604-2e22b6241e5c465b88336b821b1d7f2c.jpg?w=1200&resize=1200,0&ssl=1 "Understanding Nominal vs. Actua; Sizes in Lumber")
In case you’re new to buying lumber for craft duties or dwelling enchancment work, certainly one of many first stuff you uncover is that the dimensions by which the wood is obtainable (nominal measurements) normally usually are not the an identical as a result of the wood’s exact measurements. For example, the exact measurement of two x 10 framing lumber is about 1 1/2 inches thick and 9 1/4 inches in depth whereas a bit of 1 x 4 pine, actually measures 3/4 inch thick and three 1/2 inch in depth.
To further confuse points, hardwood sizing necessities are fully totally different than softwood necessities, and hardwood is commonly provided by a unit of amount typically generally known as the board foot, not by board dimension. All of this might make points significantly sophisticated when looking for lumber to make a endeavor to specific dimensions.
Nominal vs. Exact Measurements of Dimension Lumber
The time interval dimension lumber is used for softwood species (much like pine or fir) utilized inside the developing trades for framing and totally different carpentry makes use of. Historic practices inside the lumber enterprise make clear why the nominal dimension of this lumber (what the wood generally known as) is greater than the exact dimensions.
Initially, a 2 x 4 was scale back as a tricky inexperienced board that was exactly 2 x 4 inches in measurement, nonetheless by the purpose the boards had been dried and planed, the boards grew to turn into smaller, approaching the now-standard 2 x 4 dimensions of 1 1/2 x 3 1/2 inches in measurement. In stylish lumber practices, the boards at the moment are not exactly 2 x 4 inches when first scale back, nonetheless as we communicate’s drying and planing methods nonetheless go away the board 1 1/2 inches thick and three 1/2 inches in depth. The outdated commonplace of calling this board a 2 x 4 stays, though in as we communicate’s lumber practices, the board has not at all been 2 x 4 inches in measurement.
Beneath are the nominal vs. exact sizes for widespread sizes of dimension lumber:
| Nominal Dimension | Exact Dimension |
|---|---|
| 1 x 2 | 3/4 x 1 1/2 inches (19 x 38 mm) |
| 1 x 3 | 3/4 x 2 1/2 inches (19 x 64 mm) |
| 1 x 4 | 3/4 x 3 1/2 inches (19 x 89 mm) |
| 1 x 5 | 3/4 x 4 1/2 inches (19 x 114 mm) |
| 1 x 6 | 3/4 x 5 1/2 inches (19 x 140 mm) |
| 1 x 8 | 3/4 x 7 1/4 inches (19 x 184 mm) |
| 1 x 10 | 3/4 x 9 1/4 inches (19 x 235 mm) |
| 1 x 12 | 3/4 x 11 1/4 inches (19 x 286 mm) |
| 2 x 2 | 1 1/2 x 1 1/2 inches (38 x 38 mm) |
| 2 x 3 | 1 1/2 x 2 1/2 inches (38 x 64 mm) |
| 2 x 4 | 1 1/2 x 3 1/2 inches (38 x 89 mm) |
| 2 x 6 | 1 1/2 x 5 1/2 inches (38 x 140 mm) |
| 2 x 8 | 1 1/2 x 7 1/4 inches (38 x 184 mm) |
| 2 x 10 | 1 1/2 x 9 1/4 inches (38 x 235 mm) |
| 2 x 12 | 1 1/2 x 11 1/4 inches (38 x 286 mm) |
| 4 x 4 | 3 1/2 x 3 1/2 inches (89 x 89 mm) |
| 4 x 6 | 3 1/2 x 5 1/2 inches (89 x 140 mm) |
| 6 x 6 | 5 1/2 x 5 12 inches (140 x 140 mm) |
Shrinkage is further pronounced laterally (all through the grain) than longitudinally (with the grain), so a board provided as an 8-foot 2 x 4 is normally very close to the whole 8 ft in dimension.
Hardwood Sizing
The sizing necessities used for hardwood lumber (much like oak, maple, birch, and mahogany) utilized in improbable cabinetry and furnishings are barely further sophisticated. Not solely are fully totally different measurement necessities used, nonetheless the sizing moreover will rely on whether or not or not the stock is surfaced on one side (S1S) or on two sides (S2S).
| Nominal Thickness | S1S | S2S |
|---|---|---|
| 1/2 inch | 3/8 inch (9.5 mm) | 5/16 inch (7.9 mm) |
| 5/8 inch | 1/2 inch (13 mm) | 7/16 inch (11 mm) |
| 3/4 inch | 5/8 inch (16 mm) | 9/16 inch (14 mm) |
| 1 (4/4) inch | 7/8 inch (22 mm) | 13/16 inch (21 mm) |
| 1 1/4 (5/4) inches | 1 1/8 inches (29 mm) | 1 1/6 inches (27 mm) |
| 1 1/2 (6/4) inches | 1 3/8 inches (35 mm) | 1 5/16 inches (33 mm) |
| 2 (8/4) inches | 1 13/16 inches (46 mm) | 1 3/4 inches (44 mm) |
| 3 (12/4) inches | 2 13/16 inches (71 mm) | 2 3/4 inches (70 mm) |
| 4 (16/4) inches | 3 13/16 inches (97 mm) | 3 3/4 inches (95mm) |
Hardwoods are hardly provided in commonplace dimensions like softwoods. Instead, suppliers sometimes promote hardwoods in a unit of amount typically generally known as the board foot. One board foot equals 144 cubic inches of wood. In numerous phrases, a 1-inch thick, 12-inch in depth, and 12-inch prolonged board includes one board foot of hardwood lumber.
Furthermore, hardwood is also provided in quarters. Each quarter refers to 1/4 inch of thickness, which means {{that a}} 5/4 board is roughly 1 1/4 inches thick. In case your endeavor requires a bit exactly 1 inch thick, you will want to purchase a 5/4 board and mill it proper right down to the right measurement using a jointer/planer.
Plywood
Plywood is commonly provided in 4 x 8-foot sheets. The commonest nominal thicknesses are 1/2 inch and three/4 inch, nonetheless as soon as extra, the exact sizes are barely fully totally different. A sheet of 1/2-inch plywood is unquestionably 15/32 inch thick, whereas a 3/4-inch sheet is 23/32 inch thick.
Plywood is graded so that each face receives a grade of A, B, C, or D, with A representing the smoothest sanded finish. For example, AA plywood has a furniture-grade finish on all sides, whereas BC plywood will in all probability be graded B on one side and C on the other.