Tangent and Normal to Curves:
The outlines of many parts of machines, instruments, apparatus and devices have of straight lines and arcs gradually merging into one another. Such type of gradual continuation of one line such as whether straight or curved is termed tangency. It is practically not possible for draftsmen to carryout tangency construction of desired accuracy without knowing the appropriate rules. Here methods of drawing tangent and common to normal engineering curves like circle, ellipse, parabola and hyperbola is explained in diagram.