10. Cone A cone is formed when a right angled triangle with an apex angle  is rotated about its altitude as the axis. (apex angle of cone 2  and imaginary lines joining the apex to circumference of the base circle is called generators

11. Circle When cutting plane is perpendicular to the axis of the cone the curve of intersection obtained is called circle Radius/ Diameter /Circumference Arc Chord Sector Quarter Circle Segment Normal Tangent Concentric circles Eccentric circles Touching circles

12. Isosceles Triangle Cutting plane passes through apex and cuts the base of the cone the curve of intersection obtained is called

13. Ellipse Cutting plane is inclined to the axis(such that  >  ) and cuts all generators

14. Parabola Cutting plane is inclined to the axis(such that  =  ) and is parallel to one of the generators of the cone

19. Designation Shape Spec Pencil Line width Point Application Border Thick Very thick line H, HB 1-1.5 Hvy rd Border of sht Visible Thick H, HB 0.75-0.96 Hvy rd Extn, edges Hidden (dotted) Medium Dash 3 mm space 1 mm H, 2H Sharp point Hidden details, edges Centre Thin sharp Chain 1long 19-38 mm short dash 3 mm space 1mm 3H SP To indicate axis/ centre Extension & Dimension Thin sharp 3 mm outside dimnsn line 10-15 from obj ln 3H, 4H 0.38-0.55 mm SP Dimensional features Section Thin sharp 3 mm apart 45 o 3H SP sectioned Cutting plane Extra Thick 1 long, 2 small and a gap H, HB 0.96-1 SP To show cutting place Short Break Thick free hand irregular H, HB 0.75-0.96 Hvy rd Short breaks Long Break Thin sharp Instrumental line 2H, 3H 0.38-0.55 Hvy rd Long spans Detto/ phantom Thin sharp 1 long 2 small and a gap 2H, 3H 0.38-0.55 SP Outline of adjacent parts Construction Very Thin Very thin line H, HB 0.1-0.2 SP Drg layout Leader Thin Thin sharp circle 10 2H 0.38-0.55 SP Prts of assy Arrow head Dark 1:3 ratio H Dark Hvy rd Limit

22. All chain lines should start and finish with a long dash Centre line should cross one another on long dash portions of the line/circles etc Centre line should extend only a short distance beyond feature unless required for dimensioning A centre line should not extend through the spaces between views A centre line should not terminate at another line

23. Long dashes should meet or cross at intersections of angle between chain lines Arcs should meet at tangent points Dashed lines should start and end with dashes in contact with the hidden or visible outlines Dashed lines should meet or cross with dashes at the intersections If a dashed line meets a curved line tangentially, it should be with solid portions of the line

27. Correct Incorrect Dimension values should be placed preferably near the middle or if unavoidable then above the extended portion of the dimension line beyond the arrowhead but preferably on the right side Dimensions should be placed outside the views. However they may be placed inside the view only if the drawing becomes clearer Correct Incorrect

28. Correct Incorrect Correct Incorrect Dimensions should be placed at sufficient distance from the object and also from each other Dimensions indicated in one view need not be repeated in another view except for the purpose of identification and clarity

29. Correct Incorrect Dimensioning to a centre line should be avoided, except when the centre line passes through the centre of a hole or a cylindrical part An axis or a contour line should never be used as a dimension line but may be used as a projection line

30. Correct Incorrect Dimensions should be marked with reference to the visible outlines rather than from the hidden lines. Dimensions should be marked from a base line of a hole or cylindrical part or finished surfaces

31. Intersection of dimension and projection line should be avoided. However if unavoidable then neither line should be broken Overall dimensions should be placed outside the intermediate dimensions. When ever an overall dimension is shown, one of the intermediate dimension is redundant and should not be dimensioned

32. If the space for the arrowhead termination is sufficient, it should be shown within the limit of dimension lines. If the space is limited, the arrowhead termination may be shown outside the intended limits of the dimension lines that are extended for that purpose. A dimensional line should be shown unbroken whenever the feature to which it refers is shown broken

34. Dimensioning Circles, Radii, Chords, Arcs and Angles

35. Dimensioning Squares, Hexagons, Chamfers and Countersinks