MOULDINGS We now touch upon what may be called the ornamental side of carpentry construction. Most details that concern this side of our subject are inheritances from the ancient Greeks and Ro mans or the later creations of Mediaeval and Renaissance times based upon them.
Mouldings are extensively used in exterior and interior trim. Their forms or types are indi cated by sectional outlines or profiles. They are classed as Roman, Grecian, and Gothic.
The Roman mouldings are all formed of parts of circles, and can therefore be struck with compasses. The Grecian are principally composed of parts of curves known as the conic sections—such as the ellipse or hyperbola. The Roman are therefore illustrated in this place as being the simpler and more generally used.
Fig. 168. This moulding is called the Ovolo or quarter round. The fillet, or straight edge projecting beyond the curved portion, is to be drawn first, and then the horizontal, which rep resents the long bottom line of the moulding. Now produce the bottom line of the fillet, and on it, from the point at which the curve is to start, mark off the width of the moulding. This point, marked 0 in the cut, is the center from which the quadrant is to be struck.
ing. This point, marked 0 in the cut, is the center from which the quadrant is to be struck.
Fig. 169 is called the Torus, or half=round. Having drawn the fillet, and the line representing the bottom of the moulding, draw a. line at right angles to these. Bisect the width of the curved part, and the bisecting point will be the center.
Fig. 170 is the Cavetto, or hollow. This is a quarter-round, the curve turning inward. It is thus precisely the reverse of the ovolo.
Fig. 171 is a section of the moulding called the Cyrna Recta. The exact form of this moulding is to a certain extent a matter of taste, since the curve may be made more or less full, as shown in the three examples, Figs. 171, 172, and 173. To describe Fig. 171, draw a perpendicular across the depth of the moulding, and bisect it. From the
bisecting point as a center point describe a quad rant ; through the center draw a horizontal line, and from the point where the quadrant already drawn touches this line mark off the radius; then from this point as a center describe the second quadrant, which will complete the form. In this and subsequent curves of combined arcs the great est care is necessary, so that the one may glide smoothly into the other without showing any break or thickening at the joining. To describe the Cyma Recta shown in Fig. 172, which is the form most generally used, let n and o be the points to be united by the moulding. Draw the line n o, and bisect it ; with half n o as a base describe an equilateral triangle on the opposite sides of the line; then the apices of the triangle will be the centers from which the curves are to be struck.
To describe Fig. 173, or others the curves of which are required to be more flat than in the last figure, draw the line n o as before, and bisect it. Bisect these two divisions again, and the centers will be on these bisecting lines, according to the form required; for, of course, the longer the radius the flatter the curve will be.
If it is required that the curve should be more full at the lower than at the upper part, it may be effected in the following manner, which is shown in Fig. 174: Having drawn n o, divide it into three equal parts ; construct an equilateral triangle, the base of which is two of these thirds, and on the opposite side of the line another, the base of which is the remaining third. The apices of these tri angles will be the centers for the curves.
Fig. 175 is the Cyan Reversa. In this mould ing the curve bulges outward at its upper part, its fulness being regulated by the taste of the designer.
Thus it may be formed of two quadrants as in Fig.
175; or of two semicircles, as in Fig. 176 ; or it may consist of the two arcs drawn from the apices of triangles as in the cyma recta already shown.