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 48
Fig. 7. This position permits the instrument to bereadily opened by pressing with the thumb and middle ringerinto the chamfered section. When the compass is opened asufficient amount, the ringers of the right hand will naturallyassume the position shown in Fig. 8. When it is held in thisposition,… … Fig. 7. Position of Hand for opening Com-pass readily when it is picked up fromDrawing-board in drawing circles up toabout 3 inches radius, withthe right hand alone. Forlarger circles, the compassshould be opened andclosed by the same method,but the thumb and index-finger of the left handshould be…
Mechanical drawing
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