Fig. 6 shows the plan of centre line of rail of a side wreath starting
from a newel. Lay down the tangents A B and B C equal in length and to
the required angle, according to circumstances, the size of the hall,
&c. The farther it stands out into the hall the better it will look,
but it must not obstruct the passage or be out of proportion to the
size of the stairs. B should be in front of the second riser, or it
will make the rail too high at the newel. A will be the face of the
newel. Draw from A square to A B, and from C square to C B to meet in
O. Then O A will be the radius of the centre line of rail, which draw.
Then A B being level will be the horizontal trace.
Fig. 7 shows the elevation. Set up a tread and risers and draw the
springing C as it occurs on the plan. Make C 3 equal C B, Fig. 6, and
draw B C S resting on the corners.
Fig. 8 shows the face mould. Draw the line A P, and make A D P equal
A D O, Fig. 6. Draw V L through P at right angles to A P. Draw D 8
parallel to V L, make D 8 equal B 3, Fig. 7; join A 8 extended to
cut V L in O; then O will be the centre. Make A B and 8 C equal A B
and D C, Fig. 6. The completion of the mould will be understood. The
tangent C B will equal C B, Fig. 7, if the drawing is correct.
Fig. 9 shows the sections which will be in the centre of plank all
round.
[Illustration: PLATE 24.]