Practical engineering drawing and third angle projection, for students in scientific, technical and manual training schools and for ... draughtsmen .. (1897)
Willson, Frederick Newton, 1855-1939 · Princeton, N.J., The author · leaf 79
Figr. lis. To obtain p = take F and F (Fig. 118) as foci; F S=d; SK at some random acute da,ngle 0 with the axis, and make S H = -■ that 0 is, make F S : S H:: b : 1. Then from F drawan arc </P, of radius less than d, and cut it atP by an arc from centre F, radius ST, Tt beinga parallel to F H;… … d .iy drawing xQ parallel to FH to meet HS prolonged; for QS will value of p, viz., €qual —7—, in which p = Fx. Again using F as a centre, and a radius Q S =. p, gives pointsR and M of the larger oval. The following are the values for the focal radii to the four points where the ovals cut theaxes.…
Mechanical drawing · Lettering
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