62 



by 2, whereas if that plank were sawed into two 1-inch boards 

 we would have the combined scales C-D plus A-B, which is 

 larger than twice C-D by A-C and D-B. The larger the 

 logs, however, the smaller the wane, that is, the smaller the 

 difference between the wide and narrow face, so that with the 

 wider planks there is no loss in scale and there is an actual 

 saving in lumber due to the fewer saw kerfs made in sawing 

 2-inch instead of 1-inch lumber. Therefore on the larger 

 logs the rule for plank exceeds that for box boards. 



Band Saw versus Circular. 



A portable mill located near Manchaug was equipped with 

 a band saw instead of a circular, so that it was possible by 

 constructing a mill tally rule at this mill to compare the results 

 of using a band saw which makes a kerf only one-eighth of an 

 inch in width with a mill tally rule represented by the general 

 Massachusetts rule, which allow for a circular saw kerf of one- 

 quarter of an inch. The two rules are printed in parallel col- 

 umns below, and a comparison will show an average gain of 20 

 per cent in the yield of pine logs by using the band saw. It 

 would seem that this saving would justify a more thorough 

 tryout of the band saw, even in connection with a portable 

 mill. 



