Rules Corner Clarification on Side Bend

– Dana Spessert, NHLA Chief Inspector

This month, I would like to take the opportunity to discuss an all too recurring subject: SIDE BEND.

Side bend is mainly created by poor sawing practices and logs with growth stresses. The drying process aggravates side bend through shrinkage at different rates within the boards.

When sawing a log, it is best to saw the front face, then the back face (180-degree rotation). This will keep the growth rings even across the board and allows the board to shrink more uniformly. In some cases, this is impossible, such as in the case of rift and quarter sawing or when sawing larger logs.

Companies have had some luck utilizing weights and other means to hold boards straight as they dry. But in my opinion, it is better to reduce the risk than to fight the natural drying process.

Now, let’s move on to the grading aspect of side bend. There is very little mention of side bend in the NHLA Rules Book. In the 2019 version of the Rules Book, on page 85, under definitions, it states:

“Side bend: A distortion of a board in which there is a deviation edgewise from a straight line from end to end of the board.”

There is another mention on page 92, under “Tips and Tricks,” paragraph 3:

“To determine the amount of side bend in a board, stand the board on its edge and measure the bend at its greatest distance from a straight line. When taking full-length cuttings, this amount must be deducted from the total width of the cutting.”

EXAMPLE: A board 6″ wide and 10′ long with a 1″ bend would allow a maximum 5″ wide, full-length cutting.”

Unfortunately, neither one of these is an actual Rule, so to help clarify, I will explain it through the definition of a Cutting; on page 9, paragraph 29, the first sentence:

“A portion of a board or plank obtained by crosscutting or ripping, or by both. ….”

A rip saw (also known as a straight-line ripsaw) only cuts in a straight line. I believe that the exclusion was not on purpose. I believe it was simply an oversite based on the knowledge that all Cuttings would be straight and without side bend.

For anyone who has not used a straight-line ripsaw to rip boards into clear pieces, I, as Chief Inspector, will state for the record that all Cuttings must be straight, and side bend is a defect that cannot be included in the Cuttings. This also includes boards that are required to be 100% clear, as in Selects. Boards utilizing the minimum width and kiln-dried Rules would also not allow any side bend.

As always, please contact me with any questions regarding the NHLA Grading Rules or to learn how the Inspection Services department can help your company be more efficient, effective, and profitable.

Chief Inspector Dana Spessert can be reached by email at or by phone at 901-399-7551.