88 



ABC OF THE STEEL SQUARE 



apply the square with the above figures on the 

 lower edge at bottom of the plumb cut, or ap- 

 ply the square as for the jack, Fig. 56, to the 

 backing line, which will give the same result as 

 17 and lOVt. 



It is quite clear that when a workman cuts a 

 common rafter, he is also cutting a timber that 

 would answer for a hip for a building of less 

 span having the same rise, only taking some 

 adjustment of the top bevel to fit against a ridge. 

 This is quite plain, and if wo refer to Fig. 58, 

 we find that the common rafter for a 1-foot run 

 becomes a hip for an 8 1 /2"^ nc h run, and that a 

 hip for a 1-foot run of t.ho building becomes a 

 common rafter for a 17-inch run. Therefore, 

 the rule that applies to the common rafter also 

 applies to the hi}) rafter, i. <., the run and rise 

 taken on the square will give the seat and plumb 

 cuts. The run and length of the rafter taken on 

 the square will give the side cuts, or taking the 

 scale for a 1-foot run, Fig. 58, it is 12 on the 

 tongue and the rise on the blade for the com- 

 mon rafter, and 17 on the tongue and rise on 

 the blade for the hip. The tongue giving the 

 seat cut and the blade the plumb cut. For the 

 side cuts we take 12 on the tongue and 15% 

 inches on the blade, and the blade will give the 

 side cut of the jack. Take 17 on the tongue 



