I am framing a large and complicated roof system with king-post truss, simple rafter trusses, and a quad valley between everything. We have finally gotten to the valleys and I have been trying to mathematically determine the jack rafter foot cuts and sq rule mortises for a 4-foot layout up the valleys. I would love to layout and cut everything on the ground. Interestingly today, we discovered that in order to get a 55 degree bevel(top face of Jack) on a 45 degree plumb cut, I set my big saw to 44.5 degrees and it works. CAn someone explain that ? I am now trying to layout the mortises for the 4-foot jack rafters running up the valley and can't find a math solution for this. Any help? (12/12 pitch; valley 7x16; jacks 6x8; 30'8 sq plan)
