One method of laying out the treads and risers around a cylinder or drum, is shown in Fig. 65. The line D shows the curve of the rail. The lines showing treads and risers may be marked off on the cylinder, or they may be marked off after the veneer is bent around the drum or cylinder.
There are various methods of making inside cylinders or wells, and of fastening same to strings. One method is shown in Fig. 66. This gives a strong joint when properly made. It will be noticed that the cylinder is notched out on the back; the two blocks shown at the back of the offsets are wedges driven in to secure the cylinder in place, and to drive it up tight to the strings. Fig. 67 shows an S-inch well hole with cylinder complete; also the method of trimming and finish ing same. The cylinder, too, is shown in such a manner that its con struction will be readily understood.
Stairs having a cylindrical or circular opening always require a weight support underneath them. This support, which is generally made of rough lumber, is called the carriage. because it is supposed to carry any reasonable load that may be placed upon the stairway. Fig. OS shows the under side of a half-space stair having a carriage beneath it. The timbers marked S are of rough stuff, and may be 2-inch by 6-inch or of greater dimensions. If they are cut to fit the risers and treads, they will require to be at least 2-inch by 8-inch.
In preparing the rough carriage for the winders, it will be best to let the back edge of the tread project beyond the back of the riser so that it forms a ledge as shown under C in Fig. 69. Then fix the cross-carriage pieces under the winders, with the back edge about flush with the backs of risers, securing one end to the well with screws, and the other to the wall string or the wall. Now cut short pieces, marked 0 0 (Fig. 6S), and fix them tightly in between the cross-carriage and the back of the riser as at B 13 in the section, Fig. 69. These carriages should be of 3-inch by 2-inch material. Now get a piece of wood, 1-inch by 3-inch, and cut pieces C C to fit tightly between the top back edge of the winders (or the ledge) and the pieces marked B B in section. This method makes a very sound and strong job of the winders; and if the stuff is roughly planed, and blocks are glued on each side of the short cross-pieces 0 0 0, it is next to impossible for the winders ever to spring or squeak. When the weight is carried in this manner, the plasterer will have very little trouble in lathing so that a graceful soffit will be made under the stairs.
The manner of placing the main stringers of the carriage S S, is shown at A, Fig. 69. Fig. 68 shows a complete half-space stair; one-half of this, finished as shown, will answer well for a quarter-space stair.
Another method of forming a carriage for a stair is shown in Fig. 70. This is a peculiar but very handsome stair, inasmuch as the first and the last four steps are parallel, but the remainder balance or dance. The treads are numbered in this illustration; and the plan of the handrail is shown tending from the scroll at the bottom of the stairs to the landing on the second story. The trimmer T at the top of the stairs is also shown; and the rough strings or carriages, R S, R S, 1f S, are represented by dotted lines.
This plan represents a stair with a curtail step, and a scroll handrail rest ing over the curve of the curtail step. This type of
stair is not now much in vogue in this country, though it is adopted occa sionally in some of the larger cities. The use of heavy newel posts instead of curtail steps, is the prevailing style at present.
In laying out geometrical stairs, the steps are arranged on prin ciples already described. The well-hole in the center is first laid down and the steps arranged around it. In circular stairs with an open well hole, the handrail being on the inner side, the width of tread for the steps should be set off at about 15 inches from the handrail, this giving an approximately uniform rate of progress for anyone ascending or descending the stairway. In stairs with the rail on the outside, as sometimes occurs, it will be sufficient if the treads have the proper width at the middle point of their length.
Where a flight of stairs will likely be subject to great stress and near, the carriages should be made much heavier than indicated in the foregoing figures; and there may be cases when it will be necessary to use iron bolts in the sides of the rough strings in order to give them greater strength. This necessity, however, will arise only in the case of stairs built in public buildings, churches, halls, factories, houses, or other buildings of a lar kind. Sometimes, even in house stairs, it may be wise to strengthen the treads and risers by spiking pieces of board to the rough string, ends up, fitting them snugly against the under side of the tread and the back of the riser. The method of doing this is shown in Fig. 71, in which the letter 0 shows the pieces nailed to the string.
Types of Stairs in Common Use. In order to make the student familiar with types of stairs in general use at the present day, plans of a few of those most likely to be met with will now be given.
Fig. 72 is a plan of a straight stair, with an ordi nary cylinder at the top provided for a return rail on the landing. It also shows a stretch-out stringer at the starting.
Fig. 73 is a plan of a stair with a landing and return steps.
Fig. 74 is a plan of a stair with an acute angular landing and cylinder.
Fig. 75 illustrates the same kind of stair as Fig. 74, the angle, however, being obtuse. Fig. 76 exhibits a stair having a half-turn with two risers on land ings.
Fig. 77 is a plan of a quarter-space stair with four winders. Fig. 78 shows a stair similar to Fig. 77, but with six winders.
Fig. 79 shows a stair having five dancing winders.
Fig. SO is a plan of a half-space stair having five dancing winders and a quarter-space landing.
Fig. SI shows a half-space stair with dancing winders all around the cylinder.
Fig. S2 shows a geometrical stair having winders all around the cylinder.
Fig. S3 shows the plan and elevation of stairs which turn around a central post. This kind of stair is frequently used in large stores and in clubhouses and other similar places, and has a very graceful appearance. It is not very difficult to build if properly planned.
The only form of stair not shown which the student may be called upon to build, would very likely be one having an elliptical plan; but, as this form is so seldom used—being found, in fact, only in public buildings or great mansions—it rarely falls to the lot of the ordinary workman to be called upon to design or construct a stairway of this type.