1. Concordia University Mechanical Engineering Drawing MECH 211/M
Lecture #2; Chapters 2, 3 and 4
Dr. John Cheung

2. Last lecture summary Third angle projection. Multi-view projection.
Miter line. Folding line.
Inclined plane. Oblique plane. Foreshortened length. True length. True surface.
Revolution of features – Minimize hidden lines - less ambiguous.

3. Quiz Rounds, Fillets & Runouts
Question:
Match the multi-view images with the sketches below.

4. Quiz Rounds, Fillets & Runouts
Question:
Match the multiview images with the sketches below.
Answers:
a) f
b) c
c) e
d) b
e) d
f) g
g) a

5. Chapter 2 CAD Systems
Any Questions?

6. Drawings Must Be
Accurate
Speed
Legibility
Neatness

7. Alphabet of Lines

8. Alphabet of Lines

9. Alphabet of Lines

10. Keeping a Sharp Edge

11. The Good and The Bad

12. Lettering

13. Fractions

14. Bisecting A Line or Arc
Draw an arc using point A somewhere close to the line centre but above and below the line.
Repeat for Point B and must use the same arc length.
Connect the two intersection points.

15. Bisecting an Angle

16. Transfer an Angle
Line A’-B’ can be anywhere.

17. Parallel Lines Through a Point
Given line AB and Point P. This is more accurate. The method on the right is faster.

18. Parallel Lines at a Given Distance

19. Dividing a Line Into Equal Parts

20. Perpendicular Line Through a Point
Given three points P, E and D. To draw a circle.
Given line A-B and Point P, draw perpendicular line from Point P.
Given line A-B and Point P, draw line from Point P perpendicular to line A-B.

21. Drawing radius in acute angle

22. Drawing arc tangent to two arcs
Largest Radius = r + R or r - R

23. In Class Exercises
Create three arbitrary points but ensure not in a line (remember points are crossed lines/arcs and not dots) – chord length of circle.
Find a circle that passes through all three points
Explain WHY your method works

24. In Class Exercise
Draw a hexagon – say M20x2.5; width across flat = 30mm.
Using the enlarging technique in 4.27 to scale it to double its size (2 times).

25. In Class Exercise Draw an arbitrary circle of radius G
Choose an arbitrary point P outside but near the circle
Choose an arbitrary radius R
Find the circle that passes through P with a radius R and is tangent to the first circle