| J1S, J2S | Jointed, Sometimes needed for wide stock. |
| S2S | Planed on both surfaces of the board. |
| S1S | Planed on one surface of the board. |
| RGH | Rough sawn lumber. |
| R1E | Straight line ripped one edge. |
| R2E | Straight line ripped two edges. |
| Resaw | A board split in half from a thicker board. |
| 4/4 | 1" rough thickness. |
| 5/4 | 1-1/4" rough thickness. |
| 6/4 | 1-1/2" rough thickness. |
| 8/4 | 2" rough thickness. |
| 10/4 | 2-1/2" rough thickness. |
| 12/4 | 3" rough thickness. |
| 16/4 | 4" rough thickness. |
| FAS | First and Seconds, the top grade for hardwoods. |
| Sel&Btr | Select & Better. Includes Select & FAS boards. |
| #1Com | Number one common grade. |
| #2Com | Number two common grade. |
Board Measure
Board feet is a unit of measure. A single board foot is one foot wide, one foot long and one inch thick or equivalent. To determine a board footage multiply its width in inches by the length in inches and by its thickness in inches and divide by 144. This will give you the total board footage in a piece of lumber.
Sapwood and HeartwoodSapwood and heartwood are allowed in any ratio. Any lumber order not specifically mentioning sapwood or heartwood, unless specificed by a particular grade, may have any amount of heartwood and sapwood. For example, a board entirely of heartwood, a board entirely of sapwood and a board half of each are identical.
StainUnless a grade specifically mentions stain, no stain is admitted in surfaced stock. If stain is admitted in a grading, the stain cannot change the hardness of the wood.
Streaks and SpotsMineral streaks and spots are admitted. Color variation may be the result of mineral streaks and spots. Mineral streaks range from olive to brown to black.
Hardwoods
Cutting
A board is made up of clear and sound portions and defects. During grading, the grader visualises the maximum clear yield of a board. A portion of a board's surface that is clear is measured. The sum of each of these clear portions is tallied and used towards grading a board. A clear portion is an imaginary rectangle extended as far as possible between defects. For example, a clear portion, a clear cut, is bordered by four knots or four edges or a combination thereof. A clear cut may be bordered by two knots and two edges. The remaining surface area of a board that is not classified as clear may be either sound or defect.
Clear Face Cutting
A cutting with no defects is classified as a clear face cutting. The reverse face must be sound for a clear face grading. If the back is worse than sound the face is not classified as clear. For example, a board with no defects on its face cannot be classified as clear if the back is riddled with unsound knots. The clear face grading relies on the back to be sound.
Sound Cutting
A sound cutting is a board that is free of rot, pith, shake and wane. A board is sound if it contains sound knots, bird pecks, stain and streaks. Soundness means the board's strength is not impaired by anything on its surface. Holes are admitted in a sound board, unless they are the entire thickness of the board, up to two 1/4" holes or one 1/2" hole per 12 cutting units.
Cutting Units
A cutting unit is an imaginary rectangle one inch wide by a foot long, exactly 1/12th of a board foot. Cutting units are used to determine the extent of surface features on a board during grading. A grader cuts the board in their imagination, different grades allow a minimum number of cutting units. For example, a board 9 3/8" wide by 16' long contains defects. A clear portion 8 1/2" x 6' yields 51 cutting units, a 3" x 9 1/2' portion yields 28 1/2, 4" x 2 3/4' yields 11 and 3" x 3 1/3' yields 10. The sum of the cutting units is 100 1/2, about 67% of the board. A board containing 67% clear cutting units is at best #1 Common. A board would never be cut this many times, it is just a method to calculate the clear portions of the board.
Hardwood Grades
F1F (FAS One Face)FAS
An FAS board must be at least 6" wide and 8' long. 83 1/3% of the board must be clear. To determine cutting units the maximum number of imaginary cuts is one-quarter of the board measure. For example, a 6" x 8' board is 4 board measure. The board can be cut only once, 1/4th of 4. After this single imaginary cut the board must be 83 1/3% clear. The area of each imaginary cut must leave at least 4" x 5' or 3" x 7' sections. If a board is 8 board measure then two cuts are allowed, yielding 83 1/3% clear, each cut at least 4" x 5' or 3" x 7'.
If a single cut in a 6" x 8' board does not yield an FAS grade there are additional rules. One additional cut is allowed in boards between 6 and 15 board measure if the resulting clear portion of the board is 91 2/3%.
The reverse face of a board must also be FAS for the entire board to be graded as FAS.
If a board face is graded to FAS but the reverse face is not, the board drops in grade. If the reverse face of a board can be graded as #1 Common, the entire board is graded as F1F. For example, if a board face grades to FAS but the reverse face only yields 82% clear the entire board is graded to at best F1F. If a board reverse face cannot be graded to #1 Common the board is not F1F.
SelectA select board is graded exactly like FAS. The only difference is that the minimum size of a Select board is 4" x 6' (whereas an FAS board must be at least 6" x 8').
The reverse face of a Select board can be either Select or #1 Common.
#1 CommonA #1 Common board must be at least 3" wide and 4' long. 66 2/3% of the board must be clear. The maximum number of imaginary cuts is one-third of the board measure plus one. Surface area after each imaginary cut must be at least 4" x 2' or 3" x 3'. For example, a board 6" x 8' is 4 board measure. One third of 4 + 1 is 1. If a single imaginary cut in the board yields 66 2/3% clear where the uncut area is at least 4" x 2' or 3" x 3', the board is graded as #1 Common.
An additional cut in the board is allowed if the resulting clear yield is at least 75%. This applies to boards between 3 and 10 board measure.
The reverse face of a #1 Common board is always #1 Common.
#2 CommonA #2 Common board must be at least 3" wide and 4' long, just like #1 Common. The clear yield of a board can be as low as 50% after cuts equal to half of the board measure. Surface area after each imaginary cut must be at least 3" x 2'. For example, a board 6" x 8 is 4 board measure and can be cut twice, half of four. The resulting clear area of the board must be at least 3" x 2' and at least 50% clear.
An additional cut is allowed in boards between 2 and 7 board measure if the yield is 66 2/3% clear.
The reverse face of a #2 Common board can be #2 Common or better. If the reverse face of a board is #3 Common then the entire board becomes #3 Common.
#3A Common#3A Common boards must be at least 3" x 4' but yield as much as 33 1/3% clear. There are unlimited imaginary cuts as long as the resulting uncut area is 3" x 2'.
A board may be graded as #3A Common if the face is #2 Common and the reverse face is structurally sound.
#3B CommonBoards at least 3" wide and 4' long with 25% clear are classified as #3B Common. There are an unlimited number of imaginary cuts with the resulting area at least 36 square inches no narrower than 1 1/2".
Special Hardwood Grading Considerations
Cherry
An unlimited number of pin knots are allowed in all grades of cherry. Each knot must be sound and no larger than 1/8" in diameter. Gum spots and streaks are also admitted in any grade without limit.
Red Oak, White Oak
Mineral streaks and spots, and streaks and spots of a similar nature, are allowed in cuttings. The total area of these streaks and spots can be no more than 8 1/3% of cuttings. Streaks and spots outside of the cuttings are allowed to any degree.
Poplar
Mineral is allowed in cuttings of Poplar up to 16 2/3% of cuttings. The limit of 16 2/3% is limited to FAS, F1F and Select faces. Faces graded #1 Common or lower there is no limit to the amount of mineral in cuttings.
Black Walnut, Butternut
In Black Walnut and Butternut graded as Select&Better the minimum cuttings sizes are 4" x 3' or 3" x 6'.
Definitions
Book Matching
Bookmatch is a set of boards that mirror one another. They have been cut from a single log and the two faces match in grain pattern and color.
Bow
Distortion of a board lengthwise. A bowed board will not be flat across its length.
Check
A crack in the surface of a board. The check does not go through the entire thickness of the board. It is a result of uneven drying, particularly by the sun and many times from too aggressive kiln drying schedule.
Crook
Distortion of a board across its width.
Cup
Distortion of a board across its width.
Heartwood
Heartwood is the dead portion of the tree. It extends from the pith(center) to the sapwood. It is usually a slightly darker shade than sapwood. The center of the tree is where the heartwood is located.
Knot
Discolored wood resulting from a branch. Red knots are living branches which the tree has overgrown. In Pine, red knots are usually sound and fixed since it grew until the tree was cut down. Black knots are dead wood, from dead branches, which are not necessarily fixed. Fixed knots are those which will only fall out of a board when under direct pressure.
Mineral Streak
Discoloration of hardwoods ranging from olive green to brown to black.
Pin Knot
Knots upto 1/8" in diameter are considered pin knots. Pin knots in Pine are up to 1/2" in diameter.
Pith
A portion of wood usually softer than the surrounding board. It occurs more often in heartwood at the center of trees. Pith that is equal hardness to the surrounding board is not a defect.
Sapwood
The living portion of the tree extending from the heartwood to the bark. Sapwood tends to be more pale than heartwood.
Sequence Match
Adjacent components of plywood are of lateral layers from the same log. Features are nearly identical across a sheet with grain lining up almost perfectly.
Shake
Seperation along the grain. It occurs most often between rings of annual growth.
Stain
Discoloration in a board. This discoloration is different than sapwood, heartwood or natural variation. It ranges from pink to gray to brown.
Twist
Distortion of a board both lengthwise and/or widthwise.
Wane
A lack of wood on the edge of a board. Wane may include bark. Wane is the result of a board being cut too close to the outside of a tree.
Warp
A term for any variation in the flatness of a board. It can include bow, crook, cup and/or twist.