A new method of grading lumber for spiral grain

A new method is presented to account for spiral grain in the grading of structural lumber. This new method requires as inputs the grain deviation angle measured on the wide faces of the piece and the ring angle measured in the end sections of the piece. It is shown that existing grading rules are either inadequate when grading lumber for spiral grain only on the basis of the grain angle on the wide faces of the piece, or unrealistic when they recommend measuring grain angle on the narrow faces of the piece, because this angle is very difficult to evaluate in practice when spiral grain is present. A comparison of current and new methods helps to demonstrate that existing grading rules underestimate the true spiral grain angle of lumber. Industrial implementation of this method would require a device for automatically recording growth ring orientation. Until such a device becomes available, the proposed method is limited to laboratory applications.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member