The length of the truck will depend somewhat on the strength of the wheels that can be had, also on the size of the boys in the fire company; but for serviceable use for both small and large boys a truck eight feet long will be a very good size. The frame or body is made of boards six inches wide, seven-eighths of an inch thick, and is eight feet long by thirty inches wide. The frame should be braced across the bottom, at the middle, and near both ends to prevent it from racking. Two cross-timbers for the axles are made fast under the forward and rear ends, and to the forward one the fifth-wheel bar is made fast so that the front wheels can be turned.
The ladder-rack is constructed from pieces of curtain-pole and side uprights, six inches wide at the bottom and tapered to three inches at the top. The uprights are attached to the inside of the body frame, and the bars on which the ladders rest are let into holes in these uprights and keyed as shown at Fig. 8 A. The end of the bar is cut across with a saw, and when this is passed through a hole in the upright a wedge-shaped key is driven in the cut to spread the end of the bar and expand it so that it will hold. Some glue on the wedge will cause it to stay in place after it has been driven in as far as it will go.
The ladders are made of two spruce rails three inches wide and one inch and a quarter thick. The rungs are let into holes made in the middle of the rails and keyed fast with wedges as just described for the ladder-rails. If a flat rung is preferred the rails may be cut in as shown at B in Fig. 8, and flat strips are to be laid in these laps and nailed or screwed fast. The sharp corners may be planed off so as to make the grip easier to the hands. The ladders may vary from seven to twelve feet in length and from eighteen to twenty-four inches wide, preferably the wider ones, as they are safer and will not slide sidewise as a narrower ladder is apt to do.
The dash-board and forward deck are supported on two bracket-plates made fast to the forward part of the body frame, and on the deck planking a box-seat with sides and back is to be made fast. Stout iron hooks are driven in along both sides of the body between forward and rear wheels, and on them ordinary wooden pails or buckets may be hung. Two sets of hooks arranged at the outer side of the ladder supports will hold the long handles of fire-hooks, and a scaling-ladder can be hung under the truck.
The goose-neck of a scaling-ladder should be made of tempered iron by a blacksmith, and all the wood-work should be of hickory. The plan for a scaling-ladder is shown in Fig. 9. The stick is three by one and a half inches and the rungs are three-quarters by two inches, driven through mortises cut in the stick twelve inches apart and held by a steel nail driven through the centre. The goose-neck base is divided like the front-wheel fork of a bicycle and with corresponding holes bored in each side. Bolts should be passed through them and the head of the stick so as to hold the iron straps securely. Good, strong hickory may be had from a wheelwright or wagon-builder, and care should be taken to cut the mortises accurately so that the parts will fit snugly together. Ladder-building is different from ordinary carpentry, and pains should be taken to have all the joints very tight so that they will not rack.
Chapter XII
WATER-WHEELS
All boys like to play about the water, and dams and water machinery afford an endless amount of amusement. Moreover, the pastime has its useful side. Once you get a wheel in operation with a shaft and pulley attached, it is then a simple matter to harness your power and make it do all sorts of things, such as sawing wood, churning milk, operating a fan on hot days, and even turning a grindstone or light wood-working machinery.
There are three kinds of wheels, the overshot, breast, and undershot. The overshot is the most powerful, for it is not only moved by the weight of water that it holds but also by the force of the onrushing water from the sluice arranged to feed it. The breast-wheel is the next in power and is used where the fall of water is not so great. The undershot wheel is employed in a rapidly running brook or stream where there is no dam or body of headwater. This form of wheel is the least powerful and the most unreliable, for the height of the watercourse is liable to change according to seasons and storms. While at one time it may be flushed up to the hub, at another the water may hardly touch the blades of the wheel.
These forms of old-style wheels have become almost obsolete now as the modern turbine has superseded it as a means of employing water as a motive power. Less than one-quarter of the surface of the old-time wheels would be actively engaged at any one time, and the waste of power was appalling as compared with the sluice-box and pen-stock of the modern turbine where every drop of water is lending its influence to the blades. A turbine, however, is rather beyond the ability of the average boy to properly construct, and so we do the best we can with the old-style wheels. For a boy’s purpose they will answer quite well enough.
In the accompanying drawings several ideas for water-wheels are shown, and among them a boy should be able to find one that he can make from boards and sticks, at a slight cost, and which if properly rigged and adjusted will develop a considerable amount of power.