Common Defects in Wood
Defects in Wood Lumber
When buying wood at a lumber yard, there are various common wood deformities that you should look for before you purchase. Some of these defects can be overcome by machining, however it will result in a loss of wood stock, and more work to make the board workable.
Bow | A curve along the face of a board that usually runs from end to end. Usually resulting from imporper storage. |  |
Check | A crack in the wood structure of a piece, usually running lengthwise. Checks are usually restricted to the end of a board and do not penetrate as far as the opposite side of a piece of sawn timber. This is easily overcome by removing the end pieces of the board. |  |
Crook | Warping along the edge from one end to the other. This is most common in wood that was cut from the centre of the tree near the pith. |  |
Cup | Warping along the face of a board across the width of the board. This defect is most common of plain-sawn lumber. |  |
Split | A longitudinal separation of the fibres which extends to the opposite face of a piece of sawn timber. |  |
Twist | Warping in lumber where the ends twist in opposite directions. Probably the worst of the defects. This board is unworkable unless it is cut into smaller pieces and flattened with a jointer. |  |
Wane | The presence of bark or absence of wood on corners of a piece of lumber. | |
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