LUMBER GRADES AND LOG GRADES 457 



7. Mechanical defects, as splits, torn grain. 



8. Wane, or round edges. 



These defects or any combination of them may reduce grade by affecting the 

 utility and value of the piece through its appearance, surface, texture, or strength. 



356. Grouping of Grades of Rough Lumber. Even when standard grades of rough 

 lumber only are considered, it is best not to attempt to base log grades or quality of 

 standing timber on the determination of given per cents of each of these standard 

 grades supposed to be contained in the logs. Instead, these grades should be com- 

 bined into a few groups with similar characteristics conforming to the grading rules 

 for the species and region. Three such groups may be distinguished in softwoods, 

 namely, finishing grades, factory or shop grades, and common grades. Based on the 

 practice of " sound " scaling, a fourth group may be made to include grades which 

 contain rot or other defects in sufficient quantity to cause their rejection in scaling 

 logs. 



Finishing grades include all of the so-called upper grades of lumber, characterized 

 by freedom from all but a few small defects. These grades are suitable for use with- 

 out being cut up, for purposes requiring appearance as the prime factor, combined 

 with definite and sometimes considerable width and length. 



These grades are used for outside and inside finish and for many purposes of 

 manufacture. The entire piece is graded as a unit, any defect serving to reduce its 

 grade as a whole. 



Factory or Shop Grades. Boards suitable for factory or shop grades are such as 

 will yield smaller pieces of upper grade material when ripped or cut up as to exclude 

 or cull out disqualifying defects. In these grades, therefore, the piece is not graded as 

 a unit but on the basis of the per cent of its volume that can be utilized. The 

 remainder is rejected as refuse and may therefore contain defects of any character 

 without affecting the grade of the piece. 



Common Grades. As applied to lumber cut from conifers or " softwoods,'' com- 

 mon lumber is distinguished from the other two groups by a general coarseness of 

 appearance caused by various defects or combinations of defects, such as nu- 

 merous large or small knots, which not only render it unsuitable for the upper grades 

 but prevent cuttings being made from it which would qualify it for factory grades. 



Common lumber of this class is graded for the entire piece and finds its principal 

 use in construction. Owing to the large volume of- common lumber, in conifers, 

 which constitutes from 60 to 95 per cent of the total output, this group may be 

 subdivided in each given region. These specific common grades are not always 

 given identical names any more than are the grades in the other two groups. The 

 most widely accepted nomenclature is, 

 No. 1 Common, 

 No. 2 Common, 

 No. 3 Common. 



367. Example of Grading Rules. Southern Yellow Pine. — Finishing, or Upper 

 Grades. " A " Finishing, inch, \\, 1| and 2-inch, dressed one or two sides, up to 

 and including 12 inches in width, must show one face practically clear of all defects, 

 except that it may have such wane as would dress off if surfaced four sides. 



13-inch and wider " A " finishing will admit two small defects or their equivalent. 



" B " Finishing, inch, \\, 1| and 2-inch, dressed one or two sides, up to and 

 including 10 inches in width, in addition to the equivalent of one split in end which 

 should not exceed in length the width of the piece, will admit any two of the following 

 or their equivalent of combined defects: slight torn grain, three pin knots, one 

 standard knot, three small pitch pockets, one standard pitch pocket, one standard 



