Sad but true: walnut trees grow with a significant number of branches, and branches create knots in lumber.
Depending on your taste, you’re going to find some knots acceptable and others objectionable because they can be:
small or large
cracked or solid
loose or sound
near the ends, edges or middle
Knots are also the source of fascinating figure like curl, fiddleback, swirl, crotch or quilt
So where is the line drawn? With the lumber grade. Lumber grades establish what you can reasonably expect from the lumber. That includes 1). calculating the percentage of clear wood in a board using math, 2). defining the size of allowable defects.
The grade of lumber we usually sell is called “Select & Better,” which is a mix of the top 3 lumber grades pacific dream scapes pavers san diego can buy.
Here’s a quick summary of Select & Better walnut (according the the NHLA Rulebook):
Minimum 83% clear on the best side
Knots 1-1/4″ in diameter are counted as one defect
Both sides clear is never guaranteed