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Fig. 15. — Machine Shop of one story, Slow-Burning Construction, of Brick and Wood.

addition are supported by brackets, also bolted to the posts. These brackets may be of either hard wood or of cast iron. If the latter, they may have a rib let into the post, for additional strength. If the traveling crane is to handle very heavy loads it will be necessary to support the horizontal timber by auxiliary posts bolted to the main posts and the horizontal timber resting upon

their The foundation pierson which the central posts rest should be deep and have a broad base, as they will probably be called upon to

sustain much greater weights than the foundation for the side walls, particularly if the shop is designed for heavy work.

The floors should have ample foundation support, and should be constructed by putting down from six to ten inches of broken stone or cinders, well rammed down. Upon this bed floor timbers 4 x 6 inches may be laid four feet apart,

first

applying hot tar to their under sides. These having been carefully leveled up, the spaces and all interstices under them should be carefully filled with a concrete of sand of

very clean, fine gravel, mixed with hot coal-tar. When this has thoroughly set and hardened, a floor of 3-inch planks may be spiked down. Over this, and at right angles

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with it, should be laid a 14-inch hard wood floor, which may be readily renewed when it is worn out. The floor timbers and the top floor should run lengthwise of the building and the 3-inch planks crosswise.

A concrete floor may be laid in the central portion, and the above method of plank floor be laid in the side portions.

Where the machinery to be used in the side portions of the building is of moderate weight, and the stock to be handled therein is not particularly heavy, the foundations for the floor need not be of such a substantial character as that described. Probably four or six inches of broken stone or cinders will be quite sufficient for the purpose. The floor planks, too, may be lighter. say 2-inch for the main floor and it for the top floor, and the floor timbers 4x4 inches.

It is assumed that in all cases the ground has been properly prepared and leveled

up before the crushed stone or cinder bed is put down. For this very necessary preparation the reader is referred to the chapter on foundations.

By lessening the depth of the foundation and reducing the thickness of the planks, the expense is considerably reduced and, under the conditions mentioned, the efficiency of the building maintained.

The roof is composed of 3-inch planks, 6 inches wide, with a groove in each edge, and joined by a separate spline, and should be 20 feet long, so as to reach over two spaces between rafters. They should break joints every six planks. Upon these planks is laid either heavy roofing paper, mopped with tar, and then thick roofing tin, or three thicknesses of roofing felt, then coated with hot tar and covered with clean gravel in the usual manner.

No gutters are necessary, the water dripping from the eaves being caught by a strip of concrete 2 feet wide all around the foundation and inclining about 2 inches. This not only takes the water from the roof, but protects the foundation from surface water.

When the building is so located, from its position with reference to other buildings, or to a yard where work is being carried on, that it is not advisable to run roof water off on the ground, gutters may be formed of tin, or better, of galvanized iron, with proper connecting pipes to carry off the water. If the gutters are formed of the roofing felt, tar, and gravel, they will have to be of rather flat sides in order to prevent the tar from running down the conductor pipes when melted by the hot summer weather.

The windows of the monitor roof may be set singly, say 31 feet wide, between the uprights supporting the roof, or they may be made with double sashes in one frame, giving two windows, 3 feet wide each. The top sash should be hung on pivots so as to be opened for ventilation. Ribbed glass will be preferable for these windows, to avoid the glaring light which plain glass would admit upon the erecting floor under the traveling crane.

The side windows may be of two or three sashes, preferably three, the upper sash pivoted and the other two sliding sashes. Ribbed glass should be used in all but the bottom sash, which will very much improve the cheerfulness of the shop by being of clear glass.

The side window frames may be made of the form shown in the back wall, the upper portion being hinged or pivoted for ventilation, and the lower portion divided into two sashes on each side; but the dark shadow cast by the center upright in a double window frame is avoided if we make the window wider and employ a single sash in width.

As will be readily seen, the entire building is designed and constructed with a view of producing a practical, efficient, and commodious structure and one that will be, at the same time, as well adapted to the special uses and purposes for which it is intended as many buildings which are much more elaborate and costly; and still to so construct it as to make it a typical example of slow-burning construction.

CHAPTER VIII

SAW-TOOTH CONSTRUCTION OF ROOFS

The newest form of shop roof. Appearance and symmetry sacrificed to utility. Perfect

illumination. Broad buildings may be properly lighted. Preferable for large areas. Economy of heating buildings with this form of roof. Roof angles. Roof construction. Steel and wood. Example of this form of building. Side walls. A high central space. Materials used in the construction. General design. Traveling cranes. Auxiliary

Distribution of power for traveling cranes. The electric system. Roof trusses of steel. Roof trusses of wood. Ventilating windows. Ribbed glass. Roof planking on steel trusses. Roof planking on wood trusses. Gutters and valleys. Conductor pipes. Economical construction.

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ONE of the most important advances in the design of machine shops and manufacturing buildings of the past few years is what is generally known as the “saw-tooth” construction of roofs.

Appearance, uniformity, and symmetry, are sacrificed to the idea of practical usefulness; the principal object being to secure as perfect and equal illumination as possible over the entire floor, whether the buildings are large or small.

Heretofore this has been one of the difficulties not entirely overcome, and in consequence of this drawback it has not been possible to construct buildings beyond a certain width, owing, in this respect, to the dark zone along the center. With this new method of lighting we may practically make them as wide as we please and be assured that the central portion is, for all practical purposes, as well lighted as near the side walls. This is a great advantage in buildings in which large and heavy machinery is to be constructed, as this class of work may be much more economically built in shops having but one story; and as the earth furnishes the best foundation for a floor for heavy weights, this is desirable on that account. By this observation it is not meant, of course, that floors are to be laid directly upon the ground.

Again, for this class of work a large area is needed, and to construct comparatively narrow buildings in order that we may have the center of the room well lighted, is expensive as well as inconvenient in moving large machines, or in working around them.

By this method of construction the buildings may be very broad and

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Fig. 16. — Longitudinal Section of Machine Shop with Saw-tooth Roof of Steel Construction.

FIG. 17. — Transverse Section of Machine Shop with Saw-tooth Roof of Steel Construction.

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