For ordinary stairs, the single step should have a riser (a, Fig. 1), between 6 1/2" and 7 1/2" high, and a tread, b, from 9" to 11". The distance between the floors, say 9' 8", is measured in the building, and is divided to obtain a riser about the proper height, giving sixteen risers, 7 1/4" high. If there are sixteen treads, and the space allowed for the stairs is 12', then it will require 9" for each.

After carefully measuring the space for the stairway, the height, width, and length, the work is laid out, cut, and partly put together in the workshop. From the height and length the pitch, or angle, V of the stairs is determined.

The details for the step are shown in Fig. 1: the riser, a, is J" thick, grooved near the bottom of its face, and the outer end cut for a miter, as shown at d. The tread is 1 3/8" or 1 1/2" thick, tongued at b for insertion into the next riser, grooved on the under side near the front for its own riser, its front edge rounded, mitered at the end, and two dovetail mortises, c, c, to receive the balusters cut into the end, as shown at e. The tread and riser, with the quarter hollow molding, are glued together: sometimes to secure a better joint, blocks are glued in the angle under the tread, as shown in Fig. 4, Exercise 20.

Fig. 2 represents the wall-string, a, grooved to receive the steps, which are forced against the front edges, with wedges glued and driven at b, b, for both tread and riser. The bottom riser is not wedged.

Fig. 3 shows the face-string, the upright edges of which are mitered as at b; the edge, c, is square, to receive the treads, which are firmly nailed near the base of the baluster. The face-string is usually stiffened by a stud or joist, as at e, Fig. 3.

A plain newel is shown in Fig. 4. The section at a shows the structure through the base and the way in which it is fastened to the riser, b, and the string, c, the tread being cut away to allow it to pass down to the floor.

Fig. 5 shows the balusters; the shorter, a, coincides with the face of the riser, the longer, b, is placed with its face one half way between the risers.

After the balusters are in position, the molding is completed on the face-string, as in the upper part of Fig. 4.

Ex. 34.

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5