1. Tangents- Definition Geometric Constructions A line is a tangent to a circle if it touches the circle at only one point

2. Tangents- Definition Geometric Constructions Two curves are tangent to each other if the touch in one and only one place

3. Geometric Constructions Tangents- Geometric location of tangent point The tangent point of a straight line and circle will lie at the intersection of a perpendicular to the straight line that passes through the center of the circle.

4. Geometric Constructions Tangents- Geometric location of tangent point The tangent point of two circles will lie on the circumferences of both circles and on a straight line connecting the circle centers

5. Straight Line Tangents to a Circle from an External point Geometric Constructions Tangents- Construction

6. Straight Line Tangents to a Circle from an External point Geometric Constructions Tangents- Construction

7. R r R-r Common Parallel Straight Line Tangents to Two Circles of Radius ‘R’ and ‘r’ Geometric Constructions Tangents- Construction

8. R r Common Parallel Straight Line Tangents to Two Circles of Radius ‘R’ and ‘r’ Geometric Constructions Tangents- Construction

9. R r R+r Common Cross Straight Line Tangents to Two Circles of Radius ‘R’ and ‘r’ Geometric Constructions Tangents- Construction

10. R r Common Cross Straight Line Tangents to Two Circles of Radius ‘R’ and ‘r’ Geometric Constructions Tangents- Construction

11. R R R R Circular Tangent of Radius ‘R’ Between a Point to a Straight Line Geometric Constructions Tangents- Construction

12. RR R R R Circular Tangent of Radius R Between Two Straight Lines at an Angle Geometric Constructions Tangents- Construction

13. R R R R+r r R R R Internal Circular Tangent of Radius ‘R’ Between a Straight Line and a Circle of Radius ‘r’ Geometric Constructions Tangents- Construction

14. R R R R-r r R R R External Circular Tangent of Radius ‘R’ Between a Straight Line and a Circle of Radius ‘r’ Geometric Constructions Tangents- Construction

15. R+r1 r2 R+r2 R r1 R+r1 R+r2 R Internal Circular Tangent of Radius ‘R’ Between Two Circles of Radius ‘r1’ and ‘r2’ Geometric Constructions Tangents- Construction

16. R-r1 r2 R-r2 R r1 R-r1 R-r2 R External Circular Tangent of Radius ‘R’ Between Two Circles of Radius ‘r1’ and ‘r2’ Geometric Constructions Tangents- Construction

17. R-r1 r2 R+r2 R r1 R-r1 R+r2 R Cross Circular Tangent of Radius ‘R’ Between Two Circles of Radius ‘r1’ and ‘r2’ Geometric Constructions Tangents- Construction

18. Basic Sketching Line types Visible Object – Thick Visible Edges and Outlines Hidden – Thin Hidden detail for like wall thickness and holes.. Center - Thin centre of a circle, cylindrical features, or a line of symmetry. Geometric Constructions 1mm 3mm 1mm 3mm 15-20mm 0.7mm HB 0.3mm 2H 0.3mm 2H

19. Line Types An Example: 1. Visible 2. Hidden 3. Center Geometric Constructions

20. Intersection of Lines Solid Line Intersections Dashed Line Intersections Gap Geometric Constructions

21. Hidden Line Conventions Geometric Constructions

22. Hidden Line Conventions Geometric Constructions

23. Centerline Conventions Extend 5mm Geometric Constructions

24. Lettering : Basic Strokes StraightSlantedCurvedHorizontal 1 1 2 3 “I” letter “A” letter 1 2 3 45 6 “B” letter Examples:

25. Geometric Constructions Lettering : Upper Case & Numerals

26. Geometric Constructions Gothic vertical style. Always use capital letters. Text height 3~5 mm. Space between lines of text is about of text height. Lettering : Rules Space between words equal to the space required for writing a letter “O”. Example: ALLDIMENSIONS ARE IN MILLIMETERS O O O O UNLESS OTHERWISE SPECIFIED. O

27. 85 R100 R85 85 R100 R85 R70 Tangents- CW 1 Geometric Constructions

28. 30 200 140 80

30. R=44 R=18 R=16+19=35 R=16 R=8 R=22-5=17 R=22+5=27 R=19 R=18+22=40 R=44+22=66 R=19

31. Geometric Constructions