CHAPTER VII 

 LOG SCALING FOR BOARD MEASURE 



80. The Log Scale. The scale of a given quantity of logs is their 

 total contents expressed in the unit of measurement employed. The 

 term " scale " also refers to the general rules or customs of scaling 

 adopted in a given region or locality, upon which depend the liberality 

 or closeness of the measurement (§ 83). Differences in the method of 

 scaling may make from 5 to 50 per cent difference in the scaled contents 

 of the same logs (Table XVII). 



To determine the contents of logs in board feet, the diameter of the 

 log is measured with a stick marked in inches, the length in feet is deter- 

 mined by measuring it with the above stick or by a tape or wheel 

 (§ 34), and the volume corresponding to these dimensions looked up in 

 the log rule.^ This process is simplified by placing upon the sides and 

 edges of this stick, opposite each diameter, rows of figm-es giving the 

 values of the rule for each of several standard lengths. The volume in 

 board feet is then read directly from the stick, and recorded. A stick 

 so graduated is termed a scale stick or scale rule. 



Scale sticks are made of hickory or maple about 1 by ^ inch in cross section, 

 graduated in inches, with the figures burnt into the wood (Fig. 10). Metal sticks 

 are also in use and in some regions cahper rules are used. The inch scale is on 

 one or both edges and the stick easily accommodates six or seven other rows of 

 figures corresponding to the contents in board feet of logs of as many different 

 standard 2-foot lengths. A metal tip aids in measuring the diameter inside the 

 bark. Other forms are made for scaling logs in water, or logs with ends rounded 

 or sniped. Lengths of scale sticks in inches correspond to the maximum diameters 

 of the logs to be scaled. Hexagonal scale sticks are sometimes used. Scale sticks 

 have been made which are graduated at points giving volumes to exact tens or 

 hundreds of units, but these rules have never become popular as the basis of the 

 rule is not indicated (§ 111). 



The purpose of a log scale depends upon the ownership of the timber 

 or logs. Where the logs are to be sold the scale is the basis of settle- 

 ment and must be far more carefully made than when the timber is 



1 Experienced scalers sometimes substitute ocular or paced lengths on short 

 logs. The scale of logs shorter than the minimum length given in the rule is taken 

 as equaling one- half the scale of a log twice as long as the one in question, i.e., 

 when the shortest length given on the scale is 10 feet, an 8-foot log is scaled as 

 one-half of a 16-foot log. 



