In Part 1, we explored the history of the NHLA grading system as well as some of its limitations. Then we took a look at the four basic grading categories. Now we’ll take some time to understand the details of those category requirements in a little more depth, enabling us to better understand the role of lumber grades and leverage them for our usefulness without expecting them to do what they were never designed to do.
Understanding Grading Categories
As you consider the specific characteristics of the various grading categories, you’ll notice that both Common grades and First and Seconds (FAS) include a minimum clear-cutting size; that description refers to the amount of clear, or defect-free, wood that can be cut from the board. Size also plays into the equation, which means that even a board that’s 100% clear could possibly fail to meet the requirements of the FAS category.
Defining Grading Category Terms
When the term “clear” is used, it can be synonymous with “free from defects.” A defect is anything that can interrupt a clear, or completely smooth and interruption-free surface. Some of the unallowed interruptions, or defects, may actually be aspects of lumber that serve your purpose. However, the terms remain.
A “defect,” as defined by the NHLA for grading category purposes, can include any of the following: knots, splits, checks, bark pockets, worm or grub holes, pith, wane, bird pecks, sticker stain, rot, and decay.
Limitations of the Grading Specifications
On the other hand, some distinctions that you may or may not desire to be present in your lumber are allowed and not described at all by the grading system. Included in this area are mineral streaks or tracks, burl, sticker marks that can be removed with planing, gum streaks, and transitions from sapwood to heartwood.
Hopefully you’re beginning to understand that grading categories are limited. They can’t tell you whether a particular board will work for the specific application you have in view or meet the requirements of your customer’s personal preferences. Grading categories can be a tool in helping determine such things, but they are in no way able to be the be all, end all, when it comes to your lumber order.
While some woodworkers such as furniture makers and crafters may be able to use a board that wouldn’t even qualify for the lowest category, others such as flooring manufacturers would need above-grade boards longer than the requirements of FAS. For some applications, sapwood and burl may make a board unusable, while for others that same board might be highly prized. The best way to allow the NHLA grading system to benefit you - without expecting it to do what it cannot - is to see it as a starting point. When you place a lumber order, don’t simply state the number of boards, size, species, and grade. Be ready to have a conversation about your expectations and requirements of your project.