This section is from the book "The New Metal Worker Pattern Book", by George Watson Kittredge. Also available from Amazon: The new metal worker pattern book.

Another example wherein is required a change of profile in order to produce a miter between the parts is shown in Fig. 394. In this case the angle shown in plan between the abutting members is that of an octagon, as indicated by B C D. To produce the modified profile and to describe the patterns proceed as follows: In the side B C draw the normal profile A. as indicated, and in the corresponding side, as shown in elevation by N OLK, draw a duplicate profile, as shown by A1. Divide both of these profiles into the same number of parts, and from the points in each carry lines parallel to the lines of molding in the respective views, producing the lines drawn from profile A until they meet the miter line C X. From the points thus obtained in C X erect lines vertically until they meet those drawn from profile A1, intersecting as shown from O to L. Through these points of intersection draw the line O L, which will be the miter line in elevation corresponding to C X of the plan. From the points in O L carry lines parallel with the raking molding in the direction of P indefinitely. At any convenient point outside of the raking cornice draw a duplicate of the normal profile, as shown by A2, placing its vertical line at right angles to the lines of the raking cornice. Divide the profile A2 into the same number of spaces as employed in A and A', and from these points carry lines at right angles to the lines of the raking cornice, intersecting those of corresponding number drawn from the points in 0 L. Trace a line through these intersections, as shown from R to S. Then R S will be the required profile of a raking cornice to miter against a level cornice of the profile A at an angle indicated by B C D in the plan, or an octagon angle. For the pattern of the level cornice, at right angles to the arm B C in the plan lay off a stretchout of the profile A, as shown by E F, through the points in which draw the usual measuring line. With the T-square at right angles to B C, bringing the blade successively against the several points in X C, cut corresponding measuring lines drawn through E F. Then a line traced through these points, as shown from H to G, will be the required pattern of the horizontal cornice. In like manner, for the pattern of the raking cornice, at right angles to its lines lay off a stretchout of the profile R S, as shown by U T, through the points in which draw measuring lines in the usual manner. With the T-square at right angles to the lines of the raking cornice, and brought successively against the points in the miter line O L, as shown in elevation, cut the corresponding measuring lines. Then a line traced through the points thus obtained, as shown by W V, will be the required pattern for the raking cornice.

Fig. 394. - From the Profile of a Given Horizontal Molding to Obtain the Profile of an Inclined Molding Necessary to Miter with it at an Octagon Angle in Plan, and the Patterns for Both Arms of the Miter.

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