Hardwood Lumber Grading
Hardwood lumber grading is a complex process using rules maintained by the National Hardwood Lumber Association (NHLA: www.natlhardwood.org). The NHLA rules were designed to provide the furniture industry a mathematically measurable method to grade lumber for its amount of clear, defect free wood.
Hardwood grades are based on the size and number of clear pieces that can be obtained from a board when it is cut up to be used to make a product. Grades are not determined by gut reactions to what a person thinks the grade should be, but actual measurements of clear sections and definitions for defects.
In practice, some of the above grades are rarely used in the commercial trade and others are typically combined. For example, lumber graded “Select & Better” would include FAS, F1F, and Select boards. No. 2A Common and No. 2B Common may be combined as “No. 2 Common”. In addition there are special rules for some species and special designations for special selections or agreements between the buyer and seller.
The upper grades, FAS, F1F and SEL, are most suitable for mouldings, joinery products such as door frames, architectural interiors and furniture requiring a high percentage of long wide cuttings. It should be noticed that FAS – the highest grade – is not synonymous with being 100% clear material.
The Common grades are likely to be most suitable for the cabinet industry, most furniture parts and flooring. Explore the use of the common grades to achieve the most value considering lumber cost and yield.
For complete details the grading rule book can be purchased from the National Hardwood Lumber Association.
While most woodworkers would like to have a large, clear, defect free board this may be a waste of a valuable resource. When selecting wood for a woodworking project, consider the size of the boards required. In many situations, smaller boards or lower grades are a more economical choice than the higher grades if small, clear pieces are required.
The standard hardwood lumber grades are summarized below:
Firsts and Seconds (FAS)
The best and most expensive grade. Boards 6″ and wider, 8′ and longer. Yields 83-1/3 percent of clear face cuttings with minimum sizes of 4″ x 5′, or 3″ x 7′. Board is graded from the poorer face. Suitable for fine furniture, cabinetry and applications where clear, wide boards are needed.
FAS One Face(F1F)
The same as FAS except the board is graded from the better face.
Face side is FAS, back side is No. 1 Common. Boards are 4″ and wider, 6′ and longer. Yields 83-1/3 percent clear face cuttings with minimum sizes of 4″ x 5′, or 3″ x 7′. A cost effective substitute for FAS when only one good face is required or smaller cuttings are acceptable.
No. 1 Common
A typical thrift or “shop” grade. Boards are 3″ and wider, 4′ and longer. Yields 66-2/3 percent clear face cuttings with minimum sizes of 4″ x 2′, or 3″ x 3′. Provides good value, especially if relatively small pieces can be used.
No. 2A & 2B Common
Boards are 3″ and wider, 4′ and longer. Yields 50 percent clear face cuttings 3″ and wider by 2′ and longer. Suitable for some paneling and flooring applications.
No. 3A Common
Boards are 3″ and wider, 4′ and longer. Yields 33-1/3 percent clear face cuttings 3″ and wider by 2′ and longer. Economical choice for rough utility applications:, crates, palettes, fencing, etc.
No. 3B Common
Boards are 3″ and wider, 4′ and longer. Yields 25 percent clear face cuttings 1-1/2″ and wider by 2′ and longer. Applications same as No. 3A Common.
Source: National Hardwood Lumber Association