Textbook of Engineering Drawing, Second Edition

4.20 Textbook of Enginnering Drawing------------------

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A ~-+--------~--------~--~ B

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120

Fig. 4.29 Concetric Circle Method

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3. Position the trammel so that the points R and Q lie respectively on the minor and major
   axes. As a rule, the third point P will always lie on the ellipse required.


4. Keeping R on the minor axis and Q on the major axis, move the trammel to Qther position
   and locate other points on the curve.
   S. Join the points by a smooth curve forming the required ellipse.

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A

120

Tramne\ Method

Fig. 4.30 Trammel Method