ABC OF THE STEEL SQUARE 27 



When the run is in inches, then in the rafter 

 table read inches and twelfths instead of feet 

 and inches. For instance: 



If with !/2 pitch the run is 12 feet 4 inches, 

 add the rafter length of 12 feet to that of 4* 

 inches, as follows: 



For run of 12 feet the 



rafter length is 16 feet 11 8-12 inches. 



For run of 4 inches the 



rafter length is 5 8-12 inches. 



Total 17 feet 5 4-12 inches. 



The brace measure on these squares is along 

 the center of the back of the tongue, and gives 

 the length of the common braces as shown in 

 Fig. 11. Examples are shown in the blade as 

 at the point marked 24 30, which means 24 

 inches on the post and 18 inches on the beam 

 or girt, which make the brace 30 inches long 

 from point to point according to the rule given. 

 An application of this rule is shown at Fig. 12, 

 where 36 inches are laid off on both post and 

 beam, which gives the length of the brace from 

 point to point 50.91 inches, or very nearly 4 

 feet 3 inches. Other dimensions are shown in 

 the square. There is also a scale of one-hun- 

 dredths, or one inch divided into 100 equal parts, 



