Elementary woodworking

This text has been prepared for the purpose of furnishing the pupil with the essential facts about  woodworking hand tools and their uses. However efficient the instruction may be and however attentive the pupil, it is impossible for him to fully grasp and comprehend during a demonstration the names of tools and technical terms, most of which are new to him. This applies with equal force to the manner of using the tools and to the methods of working.

The function of the text is to supplement the instruction of the teacher. It is intended to gather up and arrange in a logical order the facts which the pupil has has already been told. By this means these facts will become fixed in the mind of the pupil and he will work with a better understanding and make greater progress.

It is believed that the text can be used to the greatest advantage by requiring the pupil to read up the subjects presented in class immediately after the close of the lesson. Frequent rapid reviews and occasional written tests are very effective.

No course of study in the form of a series of models is presented. It is hardly possible for any two schools to follow the same series of models. Local conditions necessarily affect the choice of a course, while new and better designs are being brought out continuously.

The order in which the tools are described in the fol- lowing pages is the one that has seemed most natural. They may be taken up, however, in any convenient and logical order.

It is with the earnest hope that nature study and manual work may be closely correlated, that Part II is added. No better period can be selected in which to study trees, their leaves, bark, wood, etc., than when the student is working with wood, learning by experience its grain, hardness, color, and value in the arts.

Occasional talks on the broader topics of forestry, its economic aspects, climatic effects, influence on rainfall, the flow of rivers, floods, droughts, etc., will be found interesting as well as instructive, and such interest should be instilled into every American boy and girl.

The writer is indebted to the Fish, Forest, and Game Commission of New York state for the series of Adirondack lumbering scenes, and to the United States Bureau of Forestry for the views of California Big Trees.

EDWIN W. FOSTER.

5. Saws. The saw might be described as a succession of chisels, one back of the other. We can readily understand the action of the saw by making cuts with a narrow chisel along the grain of a piece of wood, as shown in Fig. 10 at a.

The little pieces of wood removed in this way are similar to the sawdust made by the saw, the only difference being that in the saw the teeth are narrower and the little pieces consequently smaller, and instead of one chisel dozens are being pushed forward at one time.

A saw with these chisel-shaped teeth, and used for cutting along the grain, is called a ripsaw. That this tool will not cut so readily across the grain may easily be proved by again resorting to the narrow chisel and attempting to repeat the first experiment. The wood will act as shown in Fig. 10 at 6, splitting along the grain in both directions. It is quite evident, then, that a tool for cutting across the grain must be constructed in some other way.

Continuing this experiment, let us cut the fibers with a knife point in two parallel lines across the grain, close together, as at c. It will be found that the wood between these lines may now be easily removed with the narrow chisel. This fact is made the basis on which we construct the crosscut saw. Every tooth is sharpened to a point, one on the right side, the next on the left, giving two parallel lines of sharp points designed to cut the fibers, as was done in our experiment with the knife. Fig. 12 shows the end view of the crosscut teeth enlarged. Observe that not only are the alternate teeth sharpened on opposite sides, but each tooth is bent outward from the body of the saw. This bending is called set, and is designed to make the saw cut, or kerf, wider than the thickness of the saw, that the latter may pass easily through the wood after the teeth have done their work. If it were not for this set, the fibers would spring back against the body of the saw after the teeth had passed and make the work very laborious. When a saw is properly set it should pass through the wood easily.

The teeth of the ripsaw are also set, but, as will be seen in the sketch, the bottoms are flat like a chisel instead of pointed like those of the crosscut teeth.

Beside the end views of the two kinds of teeth, the side views, which are also different, are shown in Figs. 12 and 13.

We are inclined to think of the saw as a very commonplace article, yet a careful examination will prove that the greatest care and skill are needed in its manufacture. Observe that the body, which must be of the best steel, tapers, being considerably wider at the handle than at the opposite end. This is to give strength, and to prevent 'buckling, or bending, as the tool is pushed forward.

Most delicate measurements must be made, however, to discover that not only the width but the thickness increases from A to B, and decreases from C to D. How carefully this tapering must be done can be realized when we know that the difference in thickness from A to B is only three one-thousandths of an inch, and from C to D twelve one-thousandths at end A and five one-thousandths at end B.

The saw should be held in the right hand, with the left grasping the board.
The thumb of the guide, the saw is tilted, as shown in Fig. 15, and drawn toward the worker at the first stroke. This tool should be used without exerting much pressure, in accordance with the general rule that we do our best work with tools when we work easily and deliberately.

Many varieties of saws are designed for special purposes, including those which cut stone and metal.

6. Backsaw. The backsaw is a crosscut saw with small teeth, and has a heavy steel backpiece, Fig. 17, to prevent bending. In this respect it differs from the ordinary crosscut varieties, which bend readily. The purpose of the backsaw is to make fine, straight cuts in delicate, accurate work. The steel back B is necessary on account of the thin blade, but on account of the thickness of B no cut can be made deeper than the line C. This tool will cut in any direction with reference to the grain, but is primarily a crosscut saw.