Stair-Building and the Steel Square / A Manual of Practical Instruction in the Art of Stair-Building and Hand-Railing, and the Manifold Uses of the Steel Square

by Fred. T. Hodgson; Morris Williams

Fig. 112. Finding Bevel Where Upper Tangent Inclines More Than Lower One.

The wreath is first cut from the plank square to its surface as shown in [Fig. 104]. After the application of the bevels, it is twisted, as shown in [Fig. 105], ready to be moulded; and when in position, ascending from one end of the curve to the other end, over the inclined plane of the section around the well-hole, its sides will be plumb, as shown in [Fig. 106] at b. In this figure, as also in [Fig. 105], the wreath a lies in a horizontal position in which its sides appear to be out of plumb as much as the bevels are out of plumb. In the upper part of the figure, the wreath b is shown placed in its position upon the plane of the section, where its sides are seen to be plumb. It is evident, as shown in the relative position of the wreath in this figure, that, if the bevel is the correct angle of the plane of the section whereon the wreath b rests in its ascent over the well-hole, the wreath will in that case have its sides plumb all along when in position. It is for this purpose that the bevels are needed.

Fig. 113. Finding Bevel Where Upper Tangent Inclines Less Than Lower One.

A method of finding the bevels for all wreaths (which is considered rather difficult) will now be explained:

First Case. In [Fig. 107] is shown a case where the bottom tangent of a wreath is inclining, and the top one level, similar to the top wreath shown in [Fig. 98]. It has already been noted that the plane of the section for this kind of wreath inclines to one side only; therefore one bevel only will be required to square it, which is shown at d, [Fig. 107]. A view of this plane is given in [Fig. 108]; and the bevel d, as there shown, indicates the angle of the inclination, which also is the bevel required to square the end d of the wreath. The bevel is shown applied to the end of the landing rail in exactly the same manner in which it is to be applied to the end of the wreath. The true bevel for this wreath is found at the upper angle of the pitch-board. At the end a, as already stated, no bevel is required, owing to the plane inclining in one direction only. [Fig. 109] shows a face-mould and bevel for a wreath with the bottom tangent level and the top tangent inclining, such as the piece at the bottom connecting with the landing rail in [Fig. 94].