The student, not having had wood turning as yet, will not consider
the making of the turned balusters, such work being introduced in the
course in wood turning.
In commencing work on the hand railing, notice the several parts that
have to be made; first, the newel post; second, the easing at the
bottom of the stairs; third, the straight piece of railing; fourth, the
return or twist at the top.
[Illustration: FIG. 126.]
Fig. 126 shows the working drawing for the newel post, the explanation
of which will be unnecessary. The easing is the bend in the rail before
it strikes the newel post. The method of laying out a graceful easing
is shown in Fig. 127. The straight piece of rail is worked out with the
hollow and the round planes which are to be found in the tool room.
The return or twist requires to be developed by descriptive geometry,
and to do this we will refer to drawing Fig. 121 in order to find the
diameter of the well. It will be noticed that one half of the twist is
parallel with the landing and that the curve for that half would be a
true quarter circle, while the other half of the twist, that part which
follows the incline of the stairs, would be part of an ellipse.
To demonstrate this, take a cylinder and cut it at an angle to its
axis; the section through which the cylinder was cut would be an
ellipse, an illustration of which is shown by Fig. 128. To develop this
part of the ellipse lay out, on a board, by the following method, a
full sized drawing of the rail required.
[Illustration: FIG. 127.]
[Illustration: FIG. 128.]
On the board draw a straight line which will be the center line of the
well, and on any convenient point placing the leg of the compass (which
will be set at the required radius), describe a semi-circle, which
will represent the diameter of the well given in the plan in Fig. 121.
Now from the semi-circle draw lines parallel to the center line, which
will represent the outside stringer of the stair and the casing on the
landing. Fig. 129 shows the development thus far.
The rail is to be 1¼ inches wide and the balusters to be ½ inch square.
The side of the balusters which come on the outside of the stairs
comes even with the stringer, and the rail is to be placed so that the
balusters are on its center.
From the line which is already drawn to show the part which is parallel
to the landing, draw a line for the center of the rail, and on each
side of the center line lay out half the width of the rail. On the
other half, which represents the outside stringer (the incline of
the twist), draw the center line of the rail for the straight part;
then draw lines for the width of the rail as on the other half. Now,
to obtain that part of the ellipse required, take the pitch-board E,
Fig. 122, and place it on the drawing as shown in Fig. 130; then draw
lines from points X, Y, Z, perpendicular to the center line. Now set
the compass to the distance A, B, and mark the distance A, B, on each
side of the point Y. This gives the width of the piece required for the
twist on the center line.
[Illustration: FIG. 129.]
Describe the ellipse. The major chord would be 2 (E, F,) for the
outside ellipse, and the minor chord is G, H, for the inside.
[Illustration: FIG. 130.]
There are several methods used in describing an ellipse which the
student no doubt has used in studying geometry, but the practical
stair builder uses a trammel and block. The block is grooved through
its center as shown in Fig. 131, and the trammel is a strip of wood; a
pencil is fastened on one end and pins are fixed at points to be found
by trial near the middle. Fig. 132 shows how the trammel is made. The
pins slide in the grooves of the block, and the pencil marks the curve
required.
[Illustration: FIG. 131.]
[Illustration: FIG. 132.]
[Illustration: FIG. 133.]
Fig. 133 gives a very comprehensive idea of the pieces before they are
worked down. The pieces at the right and at the top are the moulds, and
the mould for the rail is on the top of the piece which is seen in the
front of the figure.
After having laid out the lines as directed make the moulds or templets
out of thin stuff; then mark the stock (out of which the pieces of the
rail are to be made), by the templets, and saw them out, either with a
compass saw, or with the band-saw where it is convenient to do so.
It will be noticed that the piece out of which the curved or twisted
piece is made is thicker than the piece which is parallel with the
landing.
After the pieces are sawed out, proceed to lay out the lines by which
the rail is to be worked out. The templet E, Fig. 122, is used to
obtain the perpendicular and the horizontal lines, from which is drawn
the rectangle that is seen on the end of the rail, (in Fig. 133,) and
the templet seen on the right (in Fig. 133) is used to obtain the
curved lines on the top. Work off the surplus stock on each side of the
rectangle with the draw knife and the spokeshave, then work off the
top and the bottom, taking care to make a graceful curve on the top
and the bottom. Then mark the shape of the rail on the end and work out.
In Fig. 134 is seen the finished twist developed from the pieces shown
at Fig. 133.
[Illustration: FIG. 134.]