54 Kansas Academy of Science. 



the length of the hip rafter is wanted. Measuring from 17 on 

 blade to 12 on tongue ( 17 representing the length of common raf- 

 ter, and 12 the inward distance of the hip from plate to ridge, the 

 hip being the diagonal of these), the distance as shown on the rule 

 will be 20 |f , or 20 feet 10 inches. For the heel or seat cut 

 take 12 x 17 on the square, and lay on the side of the timber and 

 mark on the blade or 17-inch end, and on the tongue or 12-inch 

 end for the plumb cuts. For the side cuts against the ridge board 

 take 17 and 20-if and lay across the upper edge of the stick 

 and mark on the 20}f edge. For the backing of the hip rafter 

 dress a portion of its upper edge with a jack plane, and run 

 a gage on its center; lay the square on with the length of the hip 

 rafter or 20} f on the blade and 12 (the rise of the rafter) 

 on the tongue; mark from the gage line to edge of timber on the 

 tongue or 12-inch end, and then from the same point on center 

 gage square straight out to the same edge; the difiPerence between 

 the two points at the edge of timber will be the distance to gage 

 down on each side of the timber for the backing. Or, a bevel can 

 be set to the scribe made on the top as described, and worked to. 

 The rafter should not be backed until all the necessary framing of 

 it is done. The next thing in order will be the framing of the jack 

 rafters to fit in their places against the hip rafter. We will sup- 

 pose that the rafters are sjjaced every two feet on the plate, and as 

 we have seen that every foot gains five inches on the diagonal we 

 know that each jack will be two feet ten inches longer as they 

 range out from the angle of the plate. Dress off the upper edge 

 of one of the common rafters, and allowing first for one-half the 

 thickness of the hip rafter, space off a jack rafter every two feet 

 ten inches on said common rafter. This will give the pattern or 

 length for cutting every set of jacks. The side cut or bevel for the 

 jack will be marked from the longest point by the figures 17x12 on 

 the square ; the plumb cut will be the same as that of the common 

 rafters. To miter a purlin over or against a hip rafter, take 17 on 

 the blade and 12 on the tongue and lay on the upper edge of the 

 purlin in the direction of your cut, but this time scribe a mark on 

 the 12-inch edge of the square ; then turn the timber on its side, 

 lay on the figures, and mark precisely the same way with the same 

 figures, and the miter will be perfect, as you can test by taking the 

 piece sawed off and reversing it against the cut ; it will form the 

 correct pitch and angle. If the roof is of different pitch, then dif- 

 ferent figures will have to be used, but the principle is the same. 

 Supposing the roof has a rise of nine inches to the foot: if you 



