20 WOODWORKING 



5. Measurements and Calculations. Lumber is meas- 

 ured by the so-called board foot, which is one foot square and 

 one inch thick. 



There are two satisfactory methods of calculating the num- 

 ber of board feet in a board or a number of boards: 



Rule 1. Multiply thickness in inches by width in inches 

 by length in feet, and divide by 12. Example: 2 " x 7" x 14' 

 = 16-1/3 board feet. 



Rule 2. Multiply the thickness in inches by width in feet by 

 length in feet. Example: 2^_14. = 16 1/3 board feet. 



The possibility of cancellation in the second method makes 

 it shorter and, consequently, preferable. 



When purchasing lumber, give the dimensions in the order 

 of thickness, width and length, as: 8 pieces 5" x 9" x 12'. 



In quantities, lumber should be ordered as follows: 

 Example 1. 1000' Norway pine dressed two sides to 7/8", 

 9" and up. This makes the minimum width 9". 



Example 2. 1000' White Pine S4S 7/8" x 5" x 12'. This 

 means all boards are to be surfaced on all four surfaces and 

 the dimensions are to be uniform, viz. : 7/8" thick by 5" wide 

 by 12' long. 



6. Trees. Trees are divided into two general classes 

 known as the broadleaf, or hardwoods, and the needleleaf, or 

 softwoods. In each of these classes, there are many varieties 

 which are of great value in some one or more forms of con- 

 struction work. Those listed below are only a few of particu- 

 lar significance, either because of their general use, or because 

 of their prevalence in agricultural or industrial communities: 



