Logs are seldom consistent in their imperfections and show different stages 

 of defect and merchantability* As a result no rules for making reductions 

 can be applied inflexibly,, The amount of deduction to make is backed by - 

 the good judgment of scalers -who are familiar with the timber before them, 

 its characteristic defects, and the way it cuts out* 



Ordinarily reduction for defect can be made in one of three ways, namely : 



1, By reducing the diameter (for sap rot, etc,) 



2 By reducing the length (for butt rot, etc,) 



3o By use of diagrams (for most internal defects) 



The first two methods are self-explanatory. If sap rot or similar peripheral 

 defects are present, a reduction in diameter is appropriate e A reduction in 

 length often fits the following: butt rot 9 stump (heart) shake, sweep, 

 crook, crotch, and end broom. Most internal defects (interior decay, pitch 

 ring ? pitch seam, heart check, etc) are best handled by diagrams and the 

 diagram formula. The formula which applies is; 



Deduction (cubic feet) 



— Width (inch es) x Thickness (inch es) x Length (feet) 



— H4 — — 



i W x T x L» for a rapid mental calculation the formula can be 



restated: Deduction =5 W *,? X 1 and divid e by 10 (point off one decimal 



14 



place) o 



A similar formula which makes allowance for l/4-inch saw kerf applies to 

 scaling with board-foot log rules. This formula is: W x T x L _ deduction 



15 



(board feet of lumber). 



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