Clear-face yield
The proportion of a board’s face that will produce clear cuttings of a stated minimum size — the measurement an NHLA lumber grade is built on.
Yield is expressed in twelfths because the NHLA rules measure a board in units of twelve. FAS at 10/12 is 83-1/3%; No. 1 Common at 8/12 is 66-2/3%; No. 2A Common at 6/12 is 50%; No. 3A Common at 4/12 is 33-1/3%.
The cutting size is part of the definition and is not optional. FAS requires a minimum cutting of 4 inches by 5 feet, or 3 inches by 7 feet. No. 1 Common accepts 4 by 2 feet or 3 by 3 feet. A board can carry a high proportion of clear face and still fail a grade because the clear areas are too small to cut usefully.
Related
Terms this one depends on
- NHLA gradeA hardwood lumber grade set at the sawmill by how much clear material a board will yield when cut up — not a statement about a finished floor.
- Flooring gradeAn appearance classification for finished flooring. The standard states outright that all grades are equally strong and serviceable in any application.
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Where this definition comes from
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