High school manual training course in woodwork

This course, in its entirety, has been in daily use for nearly three years in the Richard T. Crane manual Training High School, Chicago. The greater part of it has been in use many years longer. It is the result of an experience of nearly fifteen years in high school manual training work.

It was prepared originally to save time spent by a pupil in writing in his shop note book the many helpful points suggested by his instructor. Such facts, and even the demonstrations, ought to be at the pupil's disposal for future reference, since .young people cannot grasp fully even very slow and careful explanations and demonstrations involving the use of unfamiliar tools and appliances.

The description of the equipment and prices and supplies was added to become a part of the boy's wider knowledge of his shop, and in the hope that the items may be helpful to other instructors or schools contemplating manual training.

The short studies on trees and wood are .supplemented by lectures on wood, given in the assembly hall, and illustrated by two hundred lantern slides, the property of the school. These lectures take up the preservation of forests, the effect of forests on rainfall and climate on floods and drought, tree planting, lumbering, milling, transporting, seasoning.

Cabinet making differs from Carpentry in that the wood used is generally harder - such as oak, cherry, sycamore, maple, mahogany - to work which sharper tools are required, and since the hard woods have more curly grain than the soft, the cover of the plane-bit must be set so close as to leave but a hair line of cutting edge.

In rough carpentry work joints are often made with the saw alone, and joints are nailed together, and moldings nailed on, even in the interior hard-wood finishing of houses, while in cabinet making nails are seldom used, the joints being glued and clamped together.

Carpentry work, if finished (varnished), is varnished by having the varnish flowed on - that is, two or three coats are carefully brushed on very smoothly and left just from the brush - while cabinet work is usually given from three to five coats of rubbing varnish, then rubbed down with pumice stone and water or oil, to make a perfectly true surface, and then polished, or left dead or dull.

In cabinet work, as well as in the better carpentry work, several appliances are used to force the two or more pieces of wood together to make a good glued joint. These are hand screws - hand clamps - made of iron or wood, and large iron presses for veneering (which is gluing on a common board a thin, finely grained board or sheet of wood).

These hand screws require care to use properly (Fig. 217). The jaws must be kept parallel, or the two pieces being glued will be forced apart, rather than together, as shown. The shoulder screw A, and the shoulder jaw a, turn on each other easily and freely, there being no thread in the holes of this jaw. The other jaw and screw, the clamp jaw and clamp screw do all the moving up, to tighten, so to use the hand screw properly, grasp the shoulder screw in the left hand, the clamp screw in the right, screw up or unscrew naturally, turning the whole hand screw around with the right hand, until the jaws are open far enough, then set the jaws by turning the shoulder screw with the left hand, screwing up to tighten only with the clamp screw in the right hand. An old form of hand screw, often seen in the factories, in the possession of foreigners "just over," is shown in Figure 218. Very large hand screws are too clumsy to handle, so for wide work hand clamps, made of wood or iron, are used. The back edge of the blade is notched out, that the shoulder block may be set any distance away from the clamp screw (Fig. 219). When very heavy work is required, the blade or bar is made of heavy timber and mounted on legs, while the screw is turned by a wheel of a large enough diameter to get a good leverage (Fig. 220).

Hand screws and hand clamps are sold by the length of jaw and the amount of opening, and cost from $2.00 a dozen, for small 6 in. jaws, to $20.00 a dozen.

A simple and cheap, as well as very satisfactory clamp to joint up such work as table tops, or taboret tops, is shown in Figure 221. It consists of a strip of some stiff wood and a block glued and screwed on each end. Two wedges are also required. These simple clamps, which are much used and easily made, arc shown in Figure 222.

The two or more boards to be glued must be jointed in one of two ways: the edges must be planed perfectly true and perfectly straight, or the edges may be jointed a little concave, only the thickness of one or two shavings concave, making the boards appear as shown in Figure 223, when ready to be glued. The argument in favor of the latter method is this, that no matter how well seasoned, the wood will dry faster at the open ends of the fibers than in the center of the board. By gluing with good glue, and forcing the boards together in the open center, the fibers at the ends, being under pressure, are less likely to open, and leave a hair crack at the ends of the glue joint.

A well made glue joint, using glue only, to hold two pieces of wood together, is considered quite as strong as a joint made by using dowel pins or tongues to connect the two pieces. The object of the pressure, in making all glue joints, is to force the glue entirely from between the two surfaces, up into the open pores of the wood, so that the glue, instead of lying in a layer between the two pieces, forms itself instead into hundreds of little dowels, connecting and extending up into the two pieces. A good glue joint, carefully split open with a chisel, will show these fine points of glue.

In gluing ends of wood together, it is better to size the ends first - that is, fill the open ends of the fibers by rubbing into the jointed ends thin, hot glue, with the fingers. The object of sizing is to prevent the open pores of the wood taking all the water from the glue.

Rubbed glue joints may be made by first jointing the edges perfectly straight, then rubbing the two glued surfaces together, pressing hard, until all the glue and air are rubbed out, and the pieces "stick."

Glue, to work well and hold well, should be hot, and should be thin enough to flow easily. The wood also should be placed in a heating oven, until quite warm, that the glue may not be chilled when brushed on. Cold glue is poor stuff to work with; do not expect good results in using it, because when cold it does not flow up into the open pores and dry there, clutching the pieces together, but instead lies in a thick mass between the pieces, spoiling the joint and breaking open as soon as the boards receive a shock or sharp blow.

Glue should be soaked in cold water over night if in thick pieces. If in thin pieces it softens quite easily while the water is heating.

The glue pot should be a double pot, a kettle of water outside of a pot to hold the glue. Enough cold water should be poured over the glue to cover it (some kinds of glue require much less), then this pot placed in the kettle of boiling water, the glue requiring to be stirred at intervals. To make glue at home, buy a half pound of some good, white glue for 10c. or 15c., place in a thick teacup, cover with water, then place the teacup in a tin cup full of water, and stir occasionally.