Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 109

The correct method of sawing will now be described, and some common faults in sawing pointed out, with notes on how to avoid them. The beginner has to find out or be shown the best methods, and to practise them; then proficiency and confidence will be gradually gained, and good workmanship will follow. Bad habits, once acquired, are, of course, to be overcome only by perseverance; but the pains taken will enable the workman to economise his energy, to get better results in both quantity and quality, and to reduce considerably the wear and tear of his tools. A common fault with beginners is that they do not take sufficient care at the commencement of the cut or kerf. The first part of a cut is most important, because if that is not made square through the wood it is afterwards a very difficult matter to get the cut square without twisting the saw, and perhaps spoiling it. Begin sawing by placing the left thumb (see Fig. 312) or forefinger to the line, so as to guide the saw at the commencement of the kerf, then take a few gentle and careful strokes, making sure that the saw enters the wood at right angles. Move the left hand to a more secure position, as indicated in the later figures (Figs. 314 to 316). Then, using nearly the whole length of the saw, take care not to draw it right out of the kerf, or it may be damaged by striking against the work at the return stroke; see that each stroke is regular; and allow a slight pause between each stroke to enable the worker to regain energy for each downward (working) stroke. Short, jerky, and quick strokes must be avoided, for they rapidly produce fatigue, and result in bad work. Do not force the saw: that is, do not press too hard at each downward stroke, as this fault not only leads to fatigue, but also strains the saw. Occasionally test the saw in the cut with a square to see whether it is perpendicular to the surface of the wood (see Fig. 313). The general position to be assumed in sawing is shown in Figs. 314 to 316. As far as practicable, the saw blade, marked line, and saw-cut, the eyes, shoulder, elbow, and hand, should be in one plane, much as shown in Fig. 316, which also shows the head to be over the saw, so that the operator is able to see that the saw-blade is out of winding with, and in the same plane as, the line; this is a very important point. A faulty position for hand sawing is to have the head not over the saw, but some distance to the left of it; consequently the saw leans to the left, and cuts out of the perpendicular. This fault is usually combined with another, namely, getting too far behind the tool, which attitude does not allow the operator to compare the saw with the line, because he is not able to keep his head over it, and he is also prevented from having such full command over the saw as he would have by adopting the attitude illustrated at Fig. 315, where the position is one of much greater freedom, giving at the same time much more power over the saw, with less exertion. By holding the saw in a more vertical position (as illustrated at Fig. 315), there are fewer teeth in contact with the wood at one time, and hence there is less resistance than when the saw is made to slant more nearly to the horizontal. The defect noted is that known a “laying” the saw. With thick stuff it is a good plan to square the lines down each end and line out each side, and then, during the process of sawing, to turn the wood over occasionally, and thus saw from both sides. When, however, it is desired to saw the wood entirely from one side, the blade should be tested now and again with a square, to see whether the saw is at right angles to the surface of the wood (see Fig. 313). After sawing down a foot or two, it will be found desirable to open the cut a little by inserting a screwdriver or wedge, so as to reduce the friction between the sides of the kerf and the saw-blade. Do not open the saw-kerf wide, as this tends to split the wood, and to cause the saw to wobble, thus increasing the difficulty of following the line. It is desirable to lubricate the blade with a little oil.

Fig. 312.—Beginning Saw Cut.

Fig. 313.—Testing Saw with Square.

Fig. 314.—Correct Position when Sawing.

Fig. 315.—Ripping Plank, Front View.