Hardwoods are graded by the national hardwood lumber association.
Maximum cuttings hardwood lumber grades.
Hardwood lumber is normally graded from the poorer quality face with a few exceptions such as 1f selects and surfaced lumber.
A cutting that is 5 1 2 inches wide and 4 1 3 feet long is 6 1 2x4 1 3 28 1 6 cutting units.
Each grade of hardwood lumber is determined by the size and number of clear wood cuttings which a board will yield when cut up and used in the manufacture of a hardwood product.
It is based on the number and size of the clear face cuttings rectangular pieces free of defects on the graded side that could be cut from the board being graded.
The grading of sawn wood into categories as it is processed helps to determine to a large extent the value and potential use possible for each board of sawn lumber worldwide hardwood lumber producers grade their lumber assuring downstream consumers of the lumber of the lumber s quality for the intended use.
For complete details the grading rule book can be purchased from the national hardwood lumber association.
An overview of lumber grades and wood quality.
Here s a chart to help explain the grading system.
The grading system is based therefore on the measurable percentage of clear wood that is defect free for each of the grades.
The actual number is usually fewer.
Grades are listed from highest to lowest.
Lumber is graded based on the quality and appearance of the wood.
Locate cuttings to obtain the maximum area.
Worth noting is the fact that once re sawn the cuttings obtained from the common grades will be the same clear wood as the upper grades but in smaller shorter and or narrower cuttings.
The maximum number of cuttings allowed depends on board size.
Explore the use of the common grades to achieve the most value considering lumber cost and yield.
Make sure the cuttings sizes are not below the minimum size for the trial grade.
Before we get into the different grades of lumber let s take a look at the various defects you may find in a piece of lumber.
Then calculate the cutting area.
Summary of the nhla hardwood lumber grading rules.
The common grades are likely to be most suitable for the cabinet industry most furniture parts and flooring.
These depend on various factors like the type of wood used and the number and types of defects if any.
Grade lumber requirements min.
Grading designation depends on the number of defects in a board.
The grading of hardwood reflects that.
Hardwood grading for lumber considers the size and number of pieces or cuttings which may be yielded during the creation of a hardwood product.
The other side of a clear face cutting may contain defects as long as they don t affect the strength of the cutting.
Board width inches clear cuttings poor face total yield.
A lower grade can be perfectly acceptable depending on placement and usage.
Adapted from nhla 2003.
