Posted on : 12-01-2010 | By : American Wood Source | In : Resources
The chart below shows the 8 hardwood lumber grades used most frequently today. FAS is the highest grade, No3B Common, the lowest. The grading system established by the National Hardwood Association applies to all species of wood with a few exceptions.
- FAS: First and seconds, long, wide cutting, fixtures and interior trim.
F1F: FAS 1-face, Select lumber that is 6 inches or wider, lumber is graded from better side. The better face must grade FAS, back grades not below No 1 Common.
Select: No. 1 Common lumber, poorer side grades No. 1 Common, better side grades FAS. Different from F1F only in width and length minimums.
No 1 Common: Standard Furniture Grade
No 2 Common: Standard grade for uses requiring medium to short lengths: cabinets, millwork.
No 2B Common: Similar to No. 2 except defects such as stains admitted. Paint grade.
No 3 Common: Grading based upon sound cutting rather than clear cuttings. Used for pallets and crates.
Basic Lumber Grades
| Grade | Minimum Board Width | Minimum Board Length | Minimum Cutting Size | Basic Yield | Req. Cutting Units | # of cutting | One Extra Cutting Yield |
| FAS-1F | 8″ | 8′ | 4″ x 5′ | 83 – 1/3% | SMx10 | SM/4 4 max | SMx11 |
| No 1 Common | 3″ | 4′ | 4″ x 2′ 3″ x 3′ | 66 – 2/3% | SMx6 | (SM + 1)/3 5 max | SMx9 |
| No 2 A&B Common | 3″ | 4′ | 3″ x 2′ | 50% | SMx6 | SM/2 7 max | SMx8 |
| No 3 A Common | 3″ | 4′ | 3″ x 2′ | 33 – 1/3% | SMx4 | unlimited | - |
| No 3 B Common | 3″ | 4′ | 11/2″ x 2′ approx | 25% | SMx3 | unlimited | - |
SM: surface measure
Yield determines Grade
Most hardwood grades are cutting grades. When a piece of lumber is cut into usable pieces, the ratio of the volume of parts to the volume of lumber is the yield. Below are the two possible clear cuttings of wood:
Exceptions:
- All quarter sawn woods, Butternut and Walnut are 5” and wider in FAS.
- Butternut and Walnut minimum size of clear face cuttings:
- FAS: 4″ or wider by 3′ or longer and 3″ or wider by 6′ or longer.
- No. 1 Common: Clear Face Cutting shall not contain less than 144 sq in; min width 3″ min length 2′ No limit to number of cuttings.
Consult NHLA grading rule book downloadable on their website for complete, technical grading information. http://www.natlhardwood.org
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