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 64
hored to the drawing-board asshown, gives the protractor and square a parallel motionabout the drawing. This form of parallel motion permitseither zero point on the ruling edges to be placed instantlyat any point on the drawing by a single direct movement,due to the fact that the arm formed by the… … Fig. 24. Universal Drafting Machine
Mechanical drawing
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