Elementary Course in Woodwork / Designed for use in high and technical schools, with one hundred and thirty-four illustrations: First Edition

by George Alexander Ross

PROBLEM IN HAND RAILING.

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.

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.

Fig. 127.

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.

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.

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.

Fig. 131.

Fig. 132.

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].

Fig. 134.