Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 94

Before attempting to set and sharpen saws for actual work, the beginner should practise on an old saw or on a piece of saw blade which he cannot possibly spoil. If such a vice as shown by Figs. 267 and 268, p. 71, is used, fix the bottom of it A in the bench-vice, and then place the saw between its jaws with the teeth standing about 1/2 in. above. If the saw is placed further out of the block, the action of filing will cause it to vibrate, and very soon the teeth will be stripped off the file. The teeth of an old saw will probably appear as in Figs. 283 and 284, that is to say, the teeth will be uneven and some may be longer than others. With the saw in this condition only some of the teeth can be at work, therefore they all must be brought to one common level. To accomplish this the flat file (Fig. 280, p. 73) is passed down the saw’s edge, or top of teeth, two or three times in succession, in the manner shown at Figs. 285 and 286, the former being an end view, and the latter a front view. It may now be seen by looking down the edge, as shown in Fig. 286, whether all are level. If the tooth points are not in line, those which are below the rest will not work. Hence, in sharpening, as in setting, perfect uniformity is essential to the best results. This process of filing down the teeth is called topping.

Figs. 285 and 286.—Topping Saw Teeth.

Fig. 287.—Filing Saw Teeth.