SPF Grading Rules or for 2-inch Dimension& Stud
 
PARA. 750: Bark or lack of wood from any cause, except eased edges, on the edge or corner of a piece of lumber. Wane away from end extending partially or completely across any face is permitted for one foot if no more serious than skips in dressing allowed, or across a narrow face if no more damaging than the knot hole allowed (not to exceed in length twice the diameter of the maximum knot-hole allowed in the grade) and is limited to 1 occurrence in each piece. These variations shall not be allowed in more than 5% of the pieces. This provision applies to NGR only.
 
 
 

Manufactured Holes
The area of a manufactured hole must not exceed the equivalent area of knot-hole permitted. (One manufactured hole in 12' of length, two in longer lengths.) (Must not appear on ends.)

Selected Structural - Equal in length to the diameter of hole allowed.

#1 - Equal in length to 1-1/2 times the diameter of hole allowed.

#2 - Equal in length to the width of the piece.

#3 / Stud - Equal in length to 1-1/2 times the width of the piece.

SPF Grading Rules, as per 1989 NLGA.