the left end space and equal to the right end space. 141. Inclination of a line is generally approximated by comparison with ahorizontal; sometimes with a vertical if more convenient. The eye can detect asmall error in a right angle and in parallel lines, but for intermediate angles a large ^s- ^^■… … Fig. 16. 142. For estimating angles intermediate between 0° and 90°, we naturallyhalve the quadrant getting 45°. This is always readily tested, because it is a riseof one on a base of one as shown in Fig. 16. Another angle familiar to most drafts-men is the 30°. This can be tested by the fact that…
Mechanical drawing · Lettering
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