80 A B C OF THE STEEL SQUARE 



is shown laid on the pattern with the points 1G 

 inches on the blade and 8 inches on the tongue 

 applied to the edge of the stuff. The line HO 

 on the blade gives the bevel for the foot of the 

 rafter AC. The line OP, Fig. 50 gives the 

 bevel for the top of the rafter or the plumb 

 cut, as most workmen call it. Now, there is 

 nothing in this diagram, which is from Bell's 



Fig. 50. 



Carpentry, an excellent work from which the 

 workman can get the length of his rafter, with- 

 out complicating matters. Had the figures 12 

 inches and 6 inches on the square been employed 

 instead of 16 and 8, then the distance across the 

 diagonal from these two points would have 

 equalled on the rafter, one foot on the base line 

 or seat of the rafter, so that 15 times that length 

 would have been the total length of the rafter. 



