Material. - Block of pine, 4" square and 16" long. Work. - 1. Plane the block to 3 3/4" square. 2. Practice sawing with cross-cut.

Examine the cross-cut, and note the small, pointed teeth, shown enlarged at a, Fig. 1; look down on the tops of the teeth; they appear as at b, Fig. 1; look along the saw from the handle toward the point; a depression is seen, made by the peculiar shape and set of the points of the teeth (c, Fig. 1).

Plane the block carefully to 3 3/4" square, observing instruction in Exercises 5 and 6.

Measure and mark a point on the face-edge, 1/2" from the right end. Hold the try-square, as shown at a, Fig. 2, firmly against the face-edge and coinciding with the pencil-mark. Draw a pencil-mark along the try-square. Then place the try-square in the position shown at b, Fig. 2, and again mark along the square.

Place the block on the bench-hook, with the marks toward you (Fig. 3). Hold the saw as directed in the previous exercise, the thumb used as a guide, and start the cut in the same way, beginning at the front or back of the face and on the pencil-mark. Let the weight of the saw do the cutting; give all your attention to guiding. Avoid letting the point of the saw drop at the end of the stroke. Keep the movement of the teeth as parallel as possible with the bench-top. Examine the sawed surface.

Repeat the exercise, this time using the knife for marking, and guiding the saw so that the kerf is to the right of the knife-mark.

In Fig. 4, a represents the knife-mark and c the kerf. Repeat again, this time sawing to the left of the knife-mark, as at b, Fig. 4; this last piece should be exactly 1/2" thick. Repeat the exercise with oblique cuts, as shown in Fig. 5, always measuring and adjusting the try-square on the face-edge. Fig. 6 shows the appearance under the microscope of a section of pine-wood which has been sawed by a cross-cut. The fibers are bent and broken by the sharp points, showing the tearing action of the tool.

Fig. 6

Ex .8.

Fig. 1

Fig. 2

Fig. 3

Fig. 4.

Fig. 5

Sharpening Tools. (Plate D.)