An examination of Stair Parts Fig. 4 will reveal the fact that blocks XXX are. glued or otherwise fastened in the angles formed by the junction of the treads and risers. These blocks may be beveled off as shown, or they may be left simply as square blocks. This device is to give rigidity to the work. These blocks should be put in between the carriage pieces, as the latter should, when possible, fit snug to both tread and riser and go well into the angles.
Stair Parts Fig 7
Sometimes in landing stairs and stair parts the rail finishes in a cap at the top of the newel; in such cases, the cap is turned, having its edge made in the same shape as the edge or moulding of the rail, as shown at Stair Parts Fig. 7. When this is the case, some special manipulation o f the cap is necessary to have it fit properly, as shown At Stair Parts Fig. 8. The method of finding the proper shape of the cap is shown at Stair Parts Fig. 9. The upper section shows the rail, which is supposed to be the full size; the lower section shows the cap, which may be of any reasonable diameter. Draw the plan of the cap as shown, then a section of the rail, then draw
Stair Parts Fig. 8 & 9
Stair Parts Fig. 10
the joint or miter lines as shown, and from the outside points of these lines draw parallel lines with the central line A.. Divide the stair parts into spaces as shown by the dotted lines, then at the junction with the miter lines describe semi-circles as shown, until they cut the line of diameter. Square down these lines and from them prick off the points as figured, and through these prick points describe the curves and squares; then, when mitered with the rail, there will be no over wood to remove.
To cut the miter on the stair parts cap, first prepare a cutting block similar to that shown at Fig. Io, which may be made from a piece of stuff on the face. Gauge a center line upon it and insert a dowel that will fit snugly in a corresponding hole in the cap. Next saw two kerfs in the block parallel with the gauge line, as shown at aa, and at a distance from the latter equal to the square distance of the miter line a from the center of the cap c, Fig. 8. The depth of the saw cuts below the edge of the cap, which is shown by the dotted line in Fig. to, is made equal to the length of the miter line, as shown in the plan Fig. 8. The width of the rail is marked upon the edge of the cap.. The latter is then placed on the dowel and turned around until one of the marks lies against one of the saw kerfs. The saw is then run down to the bottom of the cut, and the cap turned until the other line lies on the other kerf, when the saw is again run in to meet the first cut, which finishes the miter complete. . The foregoing method is the best and most economical for fitting the rail to the cap, but sometimes it is required that the joint shall be a true miter, which may necessitate some different treatment in forming the section of the cap. This is shown in Fig. 7, where full directions are given for laying out the lines for this kind of a cap.
Stair Parts Stair Strings
It is hardly necessary for me to say much about forming a pitch board by which stair strings are laid out, but as many of the readers of this book will be beginners in the art of stair-building, it may be well to devote a small space to this subject.
A pitch board is simply a piece of thin board, or other suitable material, and is in itself triangular. It is so cut as, to represent the rise of the step and width of tread proper. The third or long side being the "run" or "going" of the stair. A sketch of one is shown in the shaded portion of the string, Fig. 11, and its application. The dotted line running through the pitch board shows the line of nosings, and the third edge or "run" of the board. The piece below this line O is a gauge or guide which is necessary to the board, for a quick laying out of treads and risers. It will be seen that the height of the riser is laid off on one edge of the board, and the width of the tread on the other. Its application to actual work is apparent without further explanation.
Stair Parts Fig 11
Stair Parts Fig 12
The stair parts string shown in Stair Parts Fig. 11 exhibits a wide tread at the bottom, a circumstance that sometimes happens though a change of pitch should always be avoided where possible-and the string is widened out by having pieces glued to it, so that it can be "eased-off" with a gentle curve, as shown. There is also an "ease off" near the lower floor line where the base board may butt against it. This string is, of course, a wall string, and is housed to receive ends of treads and risers. The manner of housing is shown at Fig. 12, where the treads t and the risers r are shown in position and secured in place by means of wedges, x, y, which should be well, covered with good glue before being inserted, Sometimes treads are formed with two tenons at each end which fit into mortises cut in the strings. This, however, is only applicable with closed strings.
At Stair Parts Fig. 13, 1 show a housed stair parts string between newels. Here the stair parts string is double tenoned into the shanks of both newels, also relished between tenons and pinned into the shank. This string is made 12 ¾ in, wide, which is a very good width for a string of this kind, and the thickness should not be less than 1 ½ in. The upper newel is made 5' 4" long from drop to top of turned cap. These two strings are intended to be capped with a sub-rail on to which the balusters are cut or mortised in. Generally a groove the width of the square of the baluster is worked on the top of these sub-rails, and the baluster is cut to fit in this groove, then pieces of stuff made the width of the groove, and a little thicker than the groove is deep, are cut to fit in snugly between ,the squares of the baluster. This makes a solid job, and the pieces between the balusters may be made of any shape on the top, either beveled, rounded or moulded, in which case much is added to the appearance of the stairs.
Stair Parts Fig 13