Reductions In Lengths For King-Post. Suitable reduction must be made for king-post, should there be one, Fig. 76, or for rafter thicknesses should no king-post be used, Fig. 75-b. Where a king-post is used the reduction will be ½ the width of the square out of which the king-post is formed, the measurement being made square back from the line of the plumb cut, as in reducing common rafter lengths for ridge piece, Fig. 56.
Where an apex is formed as in Fig. 75-b, one pair of hips is framed each with a run equal to ½ the octagon's diagonal,with cuts at the top the same as those of common rafters. The second pair will be similarly framed but the lengths will each be reduced an amount equal to ½ the thickness of the first pair, measuring straight back from the plumb cut. The third and fourth pairs will be reduced an amount equal to ½ the diagonal thickness of the rafters already framed, measured straight back from the plumb cut, Figs. 74-a and 75-b. These rafters will have to have double side cuts as indicated in Fig. 75-b. It will be noted that these latter rafters meet the others at an angle of 45 degrees, making the framing of the side cut similar to that of a square cornered building except that these are given double cheeks.