Every cutting tool is a wedge, which is pressed or driven between the particles of the wood, pushing them apart as it advances. You have a stick of white pine half an inch square and about ten inches long. Lay it down on your bench, holding it in your left hand, and try to cut it across with your knife, about an inch from the end. Pressing down on the knife pretty hard, you force the blade in a short distance, pushing the wood right and left, and making a small notch. You soon find, however, that you cannot force the knife forward any farther; the sides of the notch resist the advance of the knife, and stop it when you have pushed it in perhaps an eighth of an inch. If you could remove the wood that presses against the sides of the knife-blade you might be able to drive it farther forward and cut deeper. You can do this if you proceed a little differently. Begin again on the opposite face of the stick, at the same distance from the end; but this time, instead of pressing squarely against the side of the piece, press obliquely in the direction of the line a b, Fig. 1.*

Exercise I. Cross-Cutting With Knife

The knife moves forward more easily, because it lifts up the fibers on one side and pushes them away, bending them as in the figure. Even now, however, the wood ceases to yield after a while, and the blade advances no farther. If you now place your knife just to the right of the former cut and cut down towards the left, in the direction of the line c d, you will cut off the ends of the fibers that are bent up, and leave a notch, as in Fig. 2.

Fig. 2.

* The crooked lines at the end of the drawing in Figs. 1, 2, 3 mean that the portion of the object to the left of such lines is left out as unnecessary. Similar lines are shown in Figs. 32, 45, and others.

Next place the knife a little to the left of the notch, and cut in the same direction as at first. You will turn up another chip, as in Fig. 3. You easily cut off this chip by cutting in the second direction (c d, Fig. 1), and can even, at the same time, by making this cut a little to the right, widen and deepen the notch. Repeating these operations, you may cut half-way through the stick.

In this exercise, as in every other operation with cutting tools, make it an invariable rule, never to cut towards your own hand. Then if your tool slips it may perhaps cut your bench, but it cannot cut you. Furthermore, it may be observed here, that in moving about the shop, you should never carry any cutting tool in your hand, unless it is absolutely necessary to do so. In such cases it must be carried with extreme care, so as not to wound yourself or any one else. Strict attention to these rules is absolutely necessary.

You have now cut half-way through your stick. Beginning on the other side, you may now make another cut to meet the first one, thus cutting the stick quite in two. Having done this once, you may cut off another piece an inch long, this time paying particular attention to the following principle. The knife, or any other tool for cutting wood, works best when, instead of pushing directly down on the tool, you at the same time draw it along. This is more important the softer the material is, and is well illustrated in cutting or carving meat, where, if we press on the knife without drawing it along we only bend the fibers instead of cutting them. You will therefore this time, as always hereafter, in using a knife or other cutting tool, particularly on soft wood, try to give it a sliding motion along with the pressure. Bearing this in mind, try now to cut off the second inch of your stick clean and smooth.

Fig. 3.

After this, cut off a third piece, working this time with the stick firmly held in the left hand instead of resting on the bench. Holding the stick thus you will have a better command of the knife, and will more readily give it the proper sliding motion; but, unless you are very careful you will run some risk of cutting yourself in making the second or backward cut. If you do not feel safe in making this cut, you may again rest the stick on the bench. To vary the exercise, you may cut the stick from all the four sides successively, leaving it nicely pointed in the form of a square pyramid.

After every exercise try to judge the quality of your work. In this last, for instance, see whether all four of the faces of the pyramid are perfectly smooth and alike, whether they meet exactly in a point, and whether the edges are straight and sharp.

If the piece of wood to be cut were three or four inches thick instead of half an inch, it might be cut off in exactly the same way with the hatchet or ax, which is only a short, heavy knife driven forward by blows instead of pressure, and without the sliding motion just described. With the hatchet or ax, just as with the knife, a blow square across the fibers will make the tool penetrate but a short distance, and to make it cut to any considerable depth the blows must be directed right and left alternately, gradually widening the cut, exactly as in the exercise with the knife, leaving the piece beveled or obliquely cut on the end. This is exactly the kind of cut that the woodman makes with his heavy ax in felling a tree, and afterwards in cutting it up into logs. You may try it with a light hatchet on a stick of pine or hemlock firewood, two or three feet long and about two inches thick. Lay it on the chopping-block, holding the end in the left hand. First strike a square blow with the hatchet, observing how little it penetrates. Next strike obliquely, right and left alternately. Be very careful not to strike very hard, nor to let the hatchet glance, lest you cut yourself. When you have cut about half through you may turn the stick over and cut from the other side; but if you do this you must work rather carefully when you have nearly cut through, for if the last stroke, which cuts through, should be delivered too squarely, or with too much force, the end piece would fly up, and might strike you in the face.

Exercise 2. Cross-Cutting With Hatchet

You have now learned that such cutting tools as the knife and the hatchet are not adapted for cutting square across the grain of wood, though they cut very well obliquely. We shall learn by and by what instrument to use when it is necessary to cut square across the grain.