LUMBER GRADES AND LOG GRADES 461 



No. 1 logs shall contain not less than six annual rings to the inch in the outer 

 portion of the log equal to one-half of the log content; and No. 1 logs shall be straight 

 grained to the extent of a variation of not more than 2 inches to the lineal foot for a 

 space of 2 lineal feet equidistant from each end of the log. 



Rings, rot, or any defect that may be eliminated in the scale, are permitted in a 

 No. 1 log, providing their size and location do not prevent the log producing the 

 required amount of No. 2 clear or better lumber. 



A No. 1 log may contain a few small knots or well scattered pitch pockets as per- 

 mitted in grades of No. 2 clear or better lumber; or may contain a very few grade 

 defects so located that they do not prevent the production of the required amount of 

 clear lumber. 



No. 2 Logs. No. 2 logs shall be not less than 12 feet in length, having defects 

 which prevent their grading No. 1, but which, in the judgment of the scaler, will 

 be suitable for the manufacture of lumber, principally in the grades of No. 1 common 

 or better. 



No 3 Logs. No. 3 logs shall be not less than 12 feet in length, having defects 

 which prevent their grading No. 2 but which, in the judgment of the scaler, will be 

 suitable for the manufacture of inferior grades of lumber. 



Cull Logs. Cull logs shall be any logs which do not contain 335 per cent of sound 

 lumber. 



Logs which contain considerable clear lumber but not sufficient to grade No. 1, 

 and contain also large coarse knots or other grade defects of No. 3 quality, will be 

 classed as No. 2 if the average value of the lumber falls in this class, regardless of its 

 actual grade. Logs which are on the border Hne between two grades should be graded 

 alternately or in equal amount in the upper and the lower grade. 



361. Mill-Grade or Mill-scale Studies. In §81 and §82 it was shown that the 

 log scale should make no attempt to measure the actual sawed contents, which is 

 the sum of the scale, plus this over-run. It is equally impossible for the scaler to 

 separate his scale into grades, for in doing so he would be compelled to substitute 

 judgment for facts; yet the actual value of logs can be determined only by a knowl- 

 edge of both of these factors. 



When the sawed output of a run of logs has been tallied and totaled separately 

 by grades, its comparison with the log scale shows for the entire quantity scaled, the 

 average over-run per thousand board feet of scale, and the per cent represented by 

 each grade produced. The value of the product of an average thousand feet B M. 

 log scale in terms of sawed lumber is determined by first multiplying the price of 

 each grade of lumber sawed by the per cent of the grade in one thousand board feet, 

 adding the bj- -products, and multiplying b}- the total per cent of over-run. 



This general check, applied to an average run of logs, and termed the mill run, 

 will serve to determine the value of similar average sizes and quality. But for 

 timber averaging larger or better, or smaller, knottier and poorer, the true value can 

 be obtained, by this method, only after sawing. 



But individual logs of similar sizes possessing certain distinctive features, as 

 shown by surface indications such as clearness, knots and other defects, will cut out 

 about the same per cent of grades and values wherever found. 



By using the log as the standard, it is possible to apply the results of mill-scale 

 studies of separate logs to stands whose average quality may be entirely different 

 from that which is being sawed, provided only that some logs of all qualities are 

 analyzed. For this reason, mill-scale studies should be based on the separate analy- 

 sis of the product of individual logs, by grades of lumber. Such studies determine, 

 for logs of each diameter, length and grade, first, the over-run in sound lumber, and 



