The wreath is shown developed in [Fig. 101] for this case; so that, with [Fig. 100] for plan, [Fig. 101] for the development of the wreath, and [Figs. 117] and [118] for finding the bevels, the method of handling any similar case in practical work can be found.
How to Put the Curves on the Face-Mould.
It has been shown how to find the angle between the tangents of the face-mould, and that the angle is for the purpose of squaring the joints at the ends of the wreath. In [Fig. 119] is shown how to lay out the curves by means of pins and a string—a very common practice among stair-builders. In this example the face-mould has equal tangents as shown at c″ and d″. The angle between the two tangents is shown at m as it will be required on the face-mould. In this figure a line is drawn from m parallel to the line drawn from h, which is marked in the diagram as “Directing Ordinate of Section.” The line drawn from m will contain the minor axes; and a line drawn through the corner of the section at 3 will contain the major axes of the ellipses that will constitute the curves of the mould.
Fig. 124. Arrangement of Risers Around Well-Hole
with Radius Larger Than One-Half Width of Tread.
