Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 104

Hand saws are made of various lengths and thicknesses, and with different degrees of fineness of teeth, to suit the several kinds of work to be done by them. It is important to bear this fact in mind when purchasing, and not to expect that a saw selected indiscriminately can be used for anything and everything. Grimshaw says that a good hand saw should be springy and elastic. It should spring regularly in proportion to its width and gauge; that is, the point should spring more than the heel, and hence the curve should not be a perfect arc of a circle. If the blade is too thick for the size of the teeth, the saw will work stiffly. If the blade is not evenly and smoothly ground, it will work hard and tend to spring. The thinner the gauge and the narrower the blade, the more need for perfectly uniform and smooth grinding. The cutting edge should have a convex curve, to adapt it to the natural rocking motion of the hand and arm. A soft saw is not economical; it costs more in a year for files and filing than a hard one, dulls sooner, works harder, and does not last so long. A saw that will take a few more minutes and a little harder work to sharpen will keep its edge and its set longer than one which can be put in order quickly, and it will work better in knots and hard wood.

Fig. 306.—Setting-block in Vice Jaws.

Figs. 307 and 308.—Hammer-setting Teeth on Plate.