Problem 41
SQUARE RETURN MITER
78. Square Return Miter.—Figure 245 shows the profile of a moulding. Mouldings are seldom of standard design, although the architect builds up a given design from standardized parts or members. In the profile shown, the compound curve is known as an ogee. This shape is encountered more frequently in mouldings than any of the others. Line 9–10 of Fig. 245 is often referred to as a "fascia," which is a plain band or surface below a moulding. Line 10–11 of Fig. 245 forms the drip of the moulding since it compels the water, flowing down the surface of the moulding, to drop off. The lines 11–12 and 12–13 are called fillets. Fillets are narrow plain surfaces used to separate curved members of a moulding, or to finish a moulding. On a moulding of this design the fillet 12–13 is intended to enter a reglet (slot) in the side wall of the building.
In drawing the ogee curve, a square, 3–A–9–B, Fig. 245, is drawn whose sides are equal in length to the desired height of the member. A horizontal center line CD is then drawn and from points C and D the curves forming the ogee are drawn. This gives an ogee whose height equals its projection. Architects often modify this curve in order to gain height without attaining too great projection.
After the profile is drawn it should have all of its curved lines divided into equal spaces. Numbers should be placed at each angular bend (vertex) and at each division of the curved fines. A line dropped from points 2 and 13 will show the entire width or projection of the moulding, Fig. 246. If this width is carried around the corner at an angle of 90°, a plan of a square return miter will result. The miter line, as shown in Fig. 246, must always bisect the angle formed by the sides of the moulding.
Lines should be dropped from every point in the profile, downward through the plan, an indefinite distance. A line of stretchout should now be drawn at right angles to the side of the plan as shown in Fig. 247. Every space in the profile is now transferred to the line of stretchout, care being taken to get them in the proper sequence, and to have the numbers correspond. Measuring lines are drawn through each division at right angles to the line of stretchout.
