This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
It is often necessary to build partitions in the story directly beneath the roof, and such partitions must extend clear up to the under side of the rafters and be connected with them in some way. This makes it necessary to cut the tops of the studs on a bevel to correspond with the pitch of the rafters, and the cutting of this bevel is not always an easy task. Fig. 207 shows the framing plan of the roof of a small simple building. In this figure A B is the ridge. The plate extends around the outside from C to D to E to F, and back again to C; and G H I J K L are the rafters. A partition H M is shown beneath the roof running diagonally across the building, making an angle with the direction of the rafters and an angle with the direction of the ridge. At N 0 is shown another partition running parallel to the ridge, and at P Q still another, running parallel to the rafters. Now since all the rafters slope upwards from the plate to the ridge, it is evident that the tops of all the studs must be cut on a bevel if they are to fit closely against the under sides of the rafters. This is illustrated in Fig. 208, where the stud A must fit against the rafter B.
To take the simplest case first, let us consider the stud marked R, Fig. 207. Since all the rafters have the same pitch or slope, all the studs in the partition N 0 will have the same bevel at the top, and if we find the bevel for one we can cut the bevel for all. Fig. 208 shows this stud drawn to a larger scale and separated from the rest; A B D C is a plan of the stud, and the rafter is shown at E F H G. We will take the distance F H, or the run of the part of the rafter shown, as one foot exactly. Now if A1 and B1 represent a side elevation of the rafter and stud, the run of the part of the rafter shown is the distance J Q, and the distance Q 0 should be equal to the rise of the rafter in one foot. Let the rise in this case be 9 inches. Then K N shows the bevel of the top of the stud. If the stud is a 2 X 4 stick, the distance K R is just 4 inches or one-third of the run of the rafter, and consequently the distance R N is just 3 inches, or one third of the rise of the rafter.
Fig. 207. Framing Plan of Roof of Simple Building.
Fig. 208. Studs Beveled to Fit Under Side of Rafter.
Fig. 209. Cutting Studs for Partition Running Parallel to Rafter.
In the case of the studs forming the partition P Q in Fig. 207, the bevel is found in the same way, the only difference being that the rafter now crosses the stud, as shown in Fig. 209, where A B C D is the stud and E F G H the rafter, both shown in plan.
In the case of the partition H M, Fig. 207, we have to deal with a somewhat more difficult problem because the rafter crosses the stud diagonally and the studs must be beveled diagonally on top so that the bevel will run from corner to corner instead of straight across the stud from side to side. An enlarged plan of one stud with the rafter running across it is shown in Fig. 210. Let A B C D be the stud and E F G H the rafter; I J L K shows the rafter in elevation looking in the direction shown by the arrow, and A1 B1 C1 D1 shows the stud as seen from this same direction. The edge D1 of the stud can not be seen from this side and is shown as a dotted line in the figure. The rafter runs across the stud, thus giving the bevel A1 B1 C1 D1 as shown in the figure.
Fig. 210. Cutting Studs for Partition Running Diagonally.