Distinguishing wood with defects from defect free clear lumber.
In spite of the apparent imperfections and limitations in the NHLA grading system, it serves the industry by providing a standard starting point from which conversations and negotiations between buyer and seller can begin. More detailed grading systems can become too difficult to employ, increasing lead times and prices due to man power involved.
Understanding the basic classifications designated by NHLA grading was discussed in “Hardwood Lumber Grading, Part 1,” and now we’ll look at what’s considered a defect, as distinguished from defect-free clear lumber. Because we’re dealing with organic materials, no two orders of 1000 board feet of 4/4 FAS Cherry or Maple will be exactly alike or well-suited to a particular project type.
The types and amounts of so-called “defects” you’re willing to accept will depend largely on the application at hand, and knowing more about the various types can help you know what questions to ask of your supplier before making a purchase. Basically, understanding the grading system will help you pick up the conversation where the grading leaves off, helping you confidently attain the lumber quality you need for each individual project.
The following “defects” that interrupt the clear face of a board include the following, according to NHLA standards:
- Bark Pockets
- Bird Pecks
- Checks
- Decay
- Grub Homes
- Knots
- Pith
- Rot
- Splits
- Sticker Stain (from kiln or air-drying sticks)
- Wane
- Worm Holes
When any of the above elements interrupt the clear face, they reduce the size of what’s considered the cutting available. Unlike the list above, some distinctive marks do not affect the integrity of the board and are therefore considered acceptable aspects of what is considered a clear cut:
- Burl
- Gum Streaks
- Mineral Streaks or Tracks (such as Glassworm in Ash)
- Sapwood-to-Heartwood transitions
- Sticker marks that can be removed with planing
Depending on the end use planned, elements from either list may be something you value as “character” rather than seeing it as a flaw. Of course, the NHLA system — or any system — simply cannot account for specific needs of various industries, no less each individual craftsman’s preference. Keep this in mind when you consider the various grades of lumber.
For instance, an 8-inch-by-9-foot board of Cherry with many knots and some rotten wood probably wouldn’t pass as a No. 2 Common board, but it may be prized by furniture makers who can create a design around the “defects” it contains.
When considering the same board, a flooring manufacturer would notice its obvious lack of consistent appearance and stability and consider it useless for his needs. At the same time, an FAS board whose “defects” include only sapwood and burl would be considered equally problematic for the flooring or window manufacturer, while a luthier or furniture maker would prize that same rejected board.
At J. Gibson McIlvain, we truly consider lumber grading the beginning of a conversation. We’re more than happy to discuss the unique needs of our customers’ projects and hand-pick orders to suit their unique needs.
