84 



THE CONSTRUCTION OF LOG RULES 



78. Choice of a Board-foot Log Rule for a Universal Standard. As 

 long as opinions and customs differ with regard to the measurement of 

 taper, scaling length, saw-kerf allowance and amount of waste in slabbing 

 which should be expressed in log rules, it will be impossible to reach 

 an agreement on a common standard. Meanwhile, custom is working 

 towards the elimination of rules which have not found favor and all but 

 about ten log rules in the United States can already be classed as obsolete. 



A log rule becomes obsolete when it ceases to be used, regardless of 

 the reasons for its disuse. Poor rules should, and sometimes do, become 

 obsolete because they do not give satisfaction. But good and con- 

 sistent rules may also become obsolete or may never be taken up, because 

 the use of other and inferior rules is so firmly intrenched that a substitu- 

 tion is impractical. Rules which scale so closely as to permit no over- 

 run will be very difficult to bring into common use, owing to the opposi- 

 tion of buyers who prefer lower standards even if inaccurate. 



The log rules whose use is sufficiently extensive to justify their con- 

 sideration, on this basis alone, for universal adoption include only the 

 following: 



Of these, the Doyle must be rejected because of its glaring inconsis- 

 tencies and the Doyle-Scribner because it combines the worst features 

 of both rules. The use of the Maine and the Spaulding rules is confined 

 to single states, and the Massachusetts rule is for a special form of 

 product; i.e., round-edged timber. 



This leaves the Scribner, preferably in Decimal C form, as the only 

 logical rule now in wide use, which is applicable to the measurement of 

 square-edged lumber. 



If the admitted irregularities of the Scribner rule are deemed so seri- 

 ous as to justify its rejection, its successor should not be chosen from 

 among the other rules in common use, but should rather be a rule based 

 on a formula and tested to conform to actual conditions of sawing. For 

 such a purpose, the International 1-inch Rule is probably as perfect a 



