Grade Application 204: Voids and Distortions

The table below provides the maximum amount of decay allowed in each grade.  Click on the image to the right as a refresher on identifying Decay in a board (Click on the image to enlarge, then click anywhere outside the image to return to the course page). View the video for a demonstration on measuring decay in a board.

Holes are measured in the same way as knots.  View the image to the right that provides a visual example of Holes in sample boards (Remember: Click on the image to enlarge, then click anywhere outside the image to return to the course page).  The following table lists the maximum allowable size of holes for each grade (or equivalent smaller, for example a 1″ hole can contain twelve 1/4″ holes).  Note that in Standard grade, two maximum size holes may be present if they are separated by 8 linear feet.

 ** Permissible only in a 5% cut for defect. 5% cut for defect will be covered in future courses.

^^ The term “sloughed” is defined as a hole created when a knot located on the edge of a board is no longer present. Typically only one wide face and one edge is affected and the hole doesn’t appear on the other wide face.

A Pocket is a well-defined opening between the growth rings.  It usually contains pitch or bark.  Well-scattered pockets are defined as pockets separated from each other by a distance at least equal to the length of the shorter pocket present. The information below lists the maximum allowable pockets permitted in each grade.  Watch the video below for valuable information about pockets.

Warp is any deviation from a true or plane surface, including Bow, Crook, Cup and Twist or any combination thereof.  The chart below provides the limitations of Warp for each grade.  Allowable warp limitations will vary dependent upon the the thickness, width and length of the board being graded.  The four forms of warp will be covered individually with instructional videos and links to charts for assistance in measuring and determining the maximum amount of each type of warp that is permitted for each grade.

IMPORTANT NOTE:  While the presence of any of the four types of Warp are permitted in all grades of Eastern White Pine, these defects in severe form are typically not desirable by the end-users.

Cup is a deviation in the face of a piece from a straight line drawn from edge to edge of a piece.  View the image to the right as a refresher in identifying Cup in a board  (Remember: Click on the image to enlarge, then click anywhere outside the image to return to the course page). It is measured at the point of greatest distance from the straight line. View the video below for instructions on how to measure Cup in a board.  Click here  to view the  Cup Table that defines the amount of cup by face width for each type of cup (Very Light, Light, Medium, and Heavy).

Bow is a deviation flatwise from a straight line drawn from end to end of a piece.  Click on the image to the right as a refresher on identifying Bow in a board (Remember: Click on the image to enlarge, then click anywhere outside the image to return to the course page).  It is measured at the point of greatest distance from the straight line. For specific measuring instructions for Bow in a board refer to the video below. Click here to view the Bow Table that defines the amount of bow by thickness and length for each degree of Bow (Very Light, Light, Medium, and Heavy).

Crook is a deviation edgewise from a straight line drawn from end to end of a piece.  View the image to the right as a refresher on identifying Crook in a board (Remember: Click on the image to enlarge, then click anywhere outside the image to return to the course page).  It is measured at the point of greatest distance from the straight line.  View the video below for instructions on how to measure Crook in a board.  Click here to view the Crook Table that defines the amount of Crook permitted for each grade by board length and face width.

Twist is a deviation flatwise, or a combination of flatwise and edgewise in the form of a curl or spiral.  View the image to the right as a refresher on identifying Twist in a board (Click on the image to enlarge, then click anywhere on the outside of the image to return to the course page). This is measured as the distance an edge of a piece at one end is raised above a flat surface against which both edges at the opposite end are resting snugly.  View the video below for instructions on how to measure Twist in a board.  Click here to view the Twist Table that defines the amount of Twist permitted in each type (Very Light, Light, Medium, and Heavy) by length and face width.