Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 93

To ascertain the angle of a saw tooth, draw a semicircle on cardboard, and mark off degrees to form a protractor (see Fig. 281). Place a 2-ft. rule on the horizontal line, and open the rule to the angle required. Draw a line D (Fig. 282) on the saw-plate; or, if the saw to be tested is a circular saw, place one part of the rule on the top of the bench table, and move the other part of the rule until it is in a line with the point of the centre tooth. If the front of the tooth corresponds with the bevel of the rule, the rake or lead is correct. If the circular saw is a large one, and the rule is not long enough to reach the tooth from the table, place a parallel block of wood on the table, and put the rule on it, or draw a line on the plate, and place the rule on the plate in a line with this line. This test applies to all hand saws mentioned in this chapter. Fig. 282 shows how to find the angle of a saw-tooth; B is the rule, C is the saw-tooth at an angle of about 65°, and D is the line on the saw-plate, or on the top of the saw-table, as the case may be.

Fig. 281.—Protractor.

Fig. 282.—Ascertaining Angle of Saw Teeth.

Figs. 283 and 284.—Unevenly Worn Teeth.