In Fig. 274, let A B D C be the elevation of a cornice at the corner of the building tor which a miter at right angles is desired. As has been explained in the chapter on the Principles of Pattern Cutting (page 77), the process of cutting a miter for a right angle admits of certain abbreviations not employed when other angles are required. The demonstration here introduced is calculated to show the method of obtaining the pattern for a square miter with the least possible labor. Divide the profile A B into any convenient number of parts, as shown by the small figures. At right angles to the lines of the molding, and in convenient proximity to it, lay off the stretchout E F, through the points in which draw measuring lines in the usual manner, parallel to the lines of the cornice, producing them far enough to intercept lines dropped vertically from points in A B. Place the T-square at right angles to the cornice, or, what is the same, parallel to the stretchout line, and, bringing it successively against all the points in the profile A B, cut measuring lines of corresponding numbers. Then a line traced through these points, as shown by G H, will be the pattern sought. The reason for this is as follows: As the angle of this miter cannot- be shown in any other view than a plan, the plan is the correct view from which to derive the pattern; having drawn which, as shown in Fig. 275, the operation of developing the pattern becomes exactly the same as in the previous problem (Fig. 273). In Pig. 274, A B DC represents the elevation of a portion of a cornice, while A B represents the profile of the return or receding portion against which the piece A B D C is required to miter, or, in other words, the miter line. As the profiles of the face piece and of the return piece are of course the same, the outline A B becomes at once the profile and the miter line; therefore that portion of the rule which says, "drop the points from the profile on to the miter line," must be omitted. All that remains then is to drop the points at once into the stretchout.
Fig. 274. - A Square Return Miter, as in a Cornice at the Corner of a Building.
Fig. 275. - Plan of a Square Return Miter.