Brooks Bros guide to Timber Grading
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.
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:
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.
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.