Hardwood Lumber Grading Can Help You Plan Your Projects
This episode focuses on hardwood lumber grading. I do get a bit into plywood grades. Softwood grading I try not to touch with a 10 foot pole. At least not without copious amounts of Scotch. I'm also lean heavily on NHLA (North American Hardwood Lumber Association) grading system because it is the most widespread system in use. European systems are also discussed specifically in terms of clear vs cutting grades.
The real point behind this is that by understanding lumber grading you can better plan your woodworking projects and your lumber shopping list. The goal is to make your lumber yard trip more successful.
"Unofficial" Lumber Grades
There are a lot of grades and terms used that I do not cover in this episode. Probably more terms missed than covered actually. This is because a lot of unofficial grades have spun up over the years as industry specifications have demanded higher grades than the NHLA system requires. "Superior", "A Grade", "B Grade", etc immediately come to mind.
When I say unofficial I don't even mean that these grades are less valid. However, without a standard set of rules you will find the interpretation of them vary from yard to yard and mill to mill. I would love to hear from any of you that have experiences with these grades and if there are questions surrounding them. Like I said in this episode, the point is to give a basic understanding rather than a comprehensive professional grading course.
I find that these other grades show up with lumber yards or industries who have very specific uses for their lumber. They have developed a classification to easily denote whether or not the lumber fits the bill for that very specific use. The problem is that same seller then lists those packs of lumber by that grade to every end user and outside of the specific use it gets confusing fast.
This is why in this episode I focus only on the standard lumber grading terms. Maybe in a future episode we can dive down the rabbit hole of some of these other grades.
Greg Nuckols says
Thanks so much for doing this podcast and keeping the lumber update alive!
I have a question about lumber terminology. At the outset I should apologize for this being a bit of a math nerd question, and also one that could come across as a criticism but which I ask because I’m honestly puzzled.
I’m not sure if it was mentioned during episode 3, but in the first two episodes you mentioned how a pack of boards might be described as something like “6-8 inches in width, with an average of 6 inches.” This puzzles me because if “average” indicates the mean (take the width of each board in the pack, add up these widths, and divide by the number of boards) then the only way the average/mean could be 6 in is if every board has width exactly 6 in. (If all boards are at least 6 in width, and at least one has width greater than 6 in, then the mean will also be at least slightly greater than 6 in.)
Does “average of 6 in” have a different meaning? I could imagine it might mean that among different exact widths in the pack (say 6in, 6.5in, 7in, 7.5in, 8in) the largest group is the 6 in width group (so the mode would be 6). Or maybe it means that the majority of the boards have width 6 in (so that the median would be 6). Or perhaps I’m just being to fussy about all this, and “average of 6 in” indicates that the mean of the widths is roughly 6.
OK, I should probably stop here! Thanks for any clarification you can offer. Again, I ask because I’m generally uncomfortable dealing with lumber yards or wholesalers because I don’t know all the terminology, and I appreciate all the information you included in episode 1.
widths and lengths are always rounded down so you can have mostly 6 and 6.25 or 6.5 or whatever under 7 and the average will be rounded down to 6. Because as we all know you can’t get a 7″ board out of 6 3/4 no matter how hard you stretch it.
Greg Nuckols says
That makes perfect sense. Thanks for the reply!
David Watterman says
Does crook, bow, or twist have any place in the grade of the lumber?
Officially? No. In that the grading rules don’t specify it. However most yards will pull boards with excessive movement out of the kiln before offering a pack for sale. Its part of the routine wastage that happens along the road of log to lumber.