Mechanical drawing; a treatise on the drawing of mechanical and machine details (1920)
Jones, Franklin Day, 1879-1967 · New York, The Industrial press; [etc., etc.] · leaf 57
Fig. 17. Simple Form of Protractor One elliptical and one spiral curve will serve for general pur-poses. In practice, the points through which a. curved lineis to be drawn are located and then the edge of the irregularcurve is made to coincide with as many of these points aspossible and a smooth… … Fig. 18. Protractor having a Pivoted Arm and Vernier Scale INSTRUMENTS AND MATERIALS 45 Many curved lines drawn by means of the irregular curverequire that the same parts of the instrument be used on eachside of a center line. The regularity of the curve drawn andthe degree of symmetry will depend…
Mechanical drawing
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