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Timber Grading

Brooks Bros Guide to Timber Grading

North American hardwood

The NHLA (National Hardwood Lumber Association) grades cover the majority of commercial hardwood species growing in the USA. The following is a brief summary of the grades, characteristics and defects of North American hardwoods.

Grades:

FAS
The FAS grade, which derives from an original grade ‘First and Seconds’, will provide the user with long, clear cuttings – best suited for high quality furniture, interior joinery and solid wood mouldings. Minimum board size is 6″ and wider and 8′ and longer. The FAS grade includes a range of boards that yield from 83.33% (ten-twelfths) to 100% clear-wood cuttings over the entire surface of the board. The clear cuttings must be a minimum size of 3″ wide by 7′ long or 4″ wide by 5′ long.

The number of these cuttings permitted depends on the size of the board, with most boards permitting one to two. The minimum width and length will vary, depending on species and whether the board is green or kiln dried. Both faces of the board must meet minimum requirements for FAS.

FAS ONE FACE (F1F) (COMMON GRADE FOR THE UK MARKET)
This grade is nearly always shipped with FAS.
The better face must meet all FAS requirements while the poor face must meet all the requirements of the Number 1 Common grade, thus ensuring the buyer with at least one FAS face. Often export shipments are assembled with an 80-20 mix (80% being the percentage of FAS boards and 20% the percentage of F1F boards). These percentages are strictly left to the individual Buyer and Seller agreement.  

Note: Minimum yield 88.33% clear wood cuttings on the poor face of the board

Walnut
Considered to be the elite of American hardwoods, Walnut is the favourite of the darker woods for fine furniture, interiors and gunstocks. Walnut grows in widely scattered stands throughout the eastern half of the United States. Historically the grading rules for FAS Walnut have been refined to encourage better use of the wood. Because of this, FAS Walnut grades allow for smaller boards, in both width and length. Natural characteristics are also admitted to a greater extent than the standard NHLA grade rules for other species.

For a more detailed explanation and what Walnut grades and products are available contact your usual or nearest Brooks Bros Sawn Timber Sales Office.

Characteristics and defects:

The following photographs illustrate characteristics that occur in North American hardwoods. Some are inherent to certain species and others are generic to all. These characteristics either occur naturally in the timber or as a result of the drying process. The grades are based on the percentage of clear, defect free wood in the board.

The NHLA grading rules allow the following characteristics in clear cutting percentages for all grades and they are therefore NOT considered defects.

norther american timber grades

Note: Although the NHLA grading rules do not consider these characteristics as defects for the standard grades, allowances are made within the individual species. For example, species such as Hard Maple and Ash are more desirable if there is a large portion of the board that is sapwood (white) and very little heartwood. The reverse is true when specifying species such as Cherry, Oak and Walnut. It is essential that the Buyers familiarise themselves not only with each species but the growing regions throughout the USA as well. Climate, soil and growing conditions such as hills and valleys all play an important role in the growth of a tree.

As previously stated, the NHLA rules are the framework to starting the trading process. For further details on characteristics found in individual species please contact your usual or nearest Brooks Bros Sawn Timber Sales Office.

The NHLA grading rules do not allow the following characteristics in the clear cuttings for all grades and they therefore ARE considered defects.

African Hardwood

In order to grade timber we need to have quality and quantity rules; in Africa there are many but only one meets the complete criteria and therefore is the one normally used.

This Grade is FAS IMPERIAL.

This particular grading rule originated in England and has been adopted by the ATIBT and is found in all OAB countries (Organisation Africaine des Bois) although in Ghana there is a little variation.

The FAS IMPERIAL system operates within certain requirements as follows: timber must be sawn at a larger dimension that specified in the contract in order to allow shrinkage that will naturally occur as the timber dries. Each pack must be representative of the species and quality offered. The limits are measured at the lower end specification of the pack, thus ensuring all other boards are of a higher quality and therefore meet at least the criteria of the grade. The timber is graded on the worst face of the board. The percentages are always calculated in volume, i.e. m³.

Grades:

40% free of defects and sap 60% maximum with defects based on the following limits and with sap not exceeding 10% of the width of the board.

Far Eastern Hardwood

Grading Far Eastern hardwood is covered by The Malaysian Grading Rules, designed for grading all hardwood timbers (except Teak) from Malaysia or adjacent territories. The most common grades imported by Brooks Bros and the UK market are the high-end Select and Better grades.

Grades:

PRIME & SELECT
Each different grade has specific requirements but there are some important factors that apply to more than one grade. Splits: This is a defect that should be excluded from all cuttings, but in any case must not exceed in aggregate length, in inches, the length of the piece in feet. Splits can only be “straight” if present in a piece (straight meaning less than 1″ deviation from parallel per foot in length of split). General: No piece may contain heart or borer holes. No piece may contain decay. Wane, other than a slight sliver on the corner, is not allowed in any piece except in Serviceable and Utility Grade. Brittle heart is not allowed in any piece except in Serviceable and Utility Grade. The different grades are as follows:

PRIME
Specification: Widths 6″ and wider, Lengths 6′ and longer.
Sapwood: Whether this is bright or not it must be excluded from clear face cuttings.
Knots: The average diameter of any sound knot must not exceed one third of the width of the face on which it appears.
Spring: This should not exceed 1″ per 12′ in length. Warp: Not admitted if sufficient to prevent the whole piece from being surfaced two sides to a standard surfaced thickness.
Cutting Requirements: The number of clear face cuttings required to make the grade will vary according to the size of the piece: one cutting from a piece of 3-4 9ft, two to five cuttings from any piece of 14ft² and over.

SELECT
Specification: Widths 5″ and wider, Lengths 6′ and longer.
Sapwood:
Unless it is greater in total than one third the width of the piece, or is present in both faces, bright sapwood will not be counted as a defect and may be included in clear face cuttings.
Knots:
As prime grade
Spring: As prime grade Warp: Other than spring, Select Grade has the same restrictions as Prime Grade. Wider pieces (greater than 10″) can be allowed if when ripped to produce two pieces they would fall within both the Select Grade and warp restrictions.
Cutting Requirements:
The number of clear face cuttings in this grade varies from one cutting from any piece 4.9ft² or less. The minimum size of clear cutting must be 4″ x 3′ = 12 units or 3″ x 4′ = 12 units.

Sawn Timbers

Black Walnut - Super Prime

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