Practical draughtsmen's work, with numerous engravings and diagrams (1903)
Hasluck, Paul N. (Paul Nooncree), 1854-1931, ed · Philadelphia, D. McKay · leaf 81
two straight-edges are placed against the major and minor axes so that thetrammel may move along by the sliding of the pins over the lines,and each quarter of the ellipse can be struck in a continuouscurve. The focus of an ellipse bears somewhat the same rela-tionship to the curve as the centre of… … Fig. 135.—Patternmakers Method of Drawing Ellipses. so-called oval bed, although he will have to make several trialsbefore he can hit upon a suitable proportion, through not knowingthe proper method of setting about the work, which is done in theway shown by Fig. 136. First set out the two centre…
Mechanical drawing
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