1. Engineering Drawing Essential Questions:
Why are engineering drawings important?
What kinds of drawings are most useful to engineers and why? 1

2. Measurement
The first step in creating and understanding engineering drawings is accurate measurement.

3. Reading a Ruler
When reading a ruler, you want to find out how far the item is from zero. When reading a ruler, you must locate the zero marking, this may vary depending on the ruler. On some rulers, the zeros start at the end, but on others it starts about 1/4 of an inch from the end. If you do not check your ruler beforehand you will not be getting an accurate measurement.

4. Types of Measurements Standard – inches, feet, yards, and miles
Metric – millimeters, centimeters, decimeters, meters, decameters, kilometers, etc.

5. Reading a Standard Ruler

6. The Standard MeasurementB C D

7. Scale
Scale is a ratio of a length used in a drawing to portray the actual length of the object.
In the drawing below, 1 inch represents 2 inches on the actual box so the scale is 1/2 or 1:2. 1”
Drawing 2”

8. Practicing Scale
Keeping with the 1:2 scale from the last slide, what would the scaled dimensions be in a drawing of the actual block shown below? Sketch the drawing and record the 1:2 scale in your design notebook.
What would the scale be
if you wanted to make it
3 times bigger?
H=2”
L=3”
W=2”
1:2 scale
H= ____ W= ____ L= ____
H=1” W=1” L=1.5”
3 times bigger would be 3:1 or 3/1

9. Practicing Scale
When writing scale as a ratio, use the same units on both sides of the colon. Do not mix units! For example:
1:4 means 1 inch: 4 inches, or 1 foot: 4 feet – not 1inch: 4 feet
What is the scale if a 4 inch length on a drawing corresponds to a 4-foot length on the actual object?
A building has a wall of windows that is 12 feet across. If a scale of 1:24 is used, how wide is the wall of windows on the drawing in inches?
1:12
6 inches

10. Practicing Scale
Car designers build models of new designs because, unlike a drawing, a model can be seen from all sides.
If you build a 1:10 model of a car that is 15 feet long, how long would the model be? Give your answer in inches.
18 inches

11. Practicing Scale
If you are a carpenter following a 1:20 blueprint for a house and you measure one wall on the blueprint to be 8 inches long, how long should you build the wall for the house? Give your answer in inches.
If you discovered that the architect who made the blueprint made a mistake, and the scale should really have been 1:25, how would you need to change the length of the wall of the house?
160 inches
It should be 200 inches. You would need to increase the wall length by 40 inches

12. 4 Types of Drawings 1. Orthographic Drawings
Shows the top, sides, and bottom of an object
Also called multi-view drawings
Should be drawn to scale

13. 4 Types of Drawings 2. Isometric Drawings
Isometric is from greek meaning “equal measure”
Depth is shown by slanting the edges up at a 30 degree angle from the horizontal
Especially useful to engineers because it shows depth, and each line is drawn to scale

14. 4 Types of Drawings 3. Oblique Drawings
Show the front, top, and one side of an object.
Front drawn as front view and horizontal edges drawn at a 45 degree angle to give the impression of depth.
Not drawn to scale, therefore not as useful to engineers

15. 4 Types of Drawings 4. Perspective Drawings
Show objects as they would appear to the naked eye, or as they would appear in a photograph
Lines showing depth converge toward an imaginary vanishing point, creating the appearance of distance

16. Hidden Lines
Hidden lines are drawn as dashed lines and show hidden features of the object (ie. Holes, false ledges, etc)
They show things you could see if you could look through objects with “X-ray vision”

17. Orthographic Drawing
Typically, you only need the front, top, and side view in an orthographic drawing
These views are two dimensional and do not show any depth…pay attention only to the faces of the object that can be seen from the side of the object you are drawing
Let’s practice identifying views…

18. Orthographic Drawing Practice
Practice identifying the views of the following objects by shading the corresponding sides with matching colors or patterns:

19. Orthographic Drawing Practice
Practice identifying the views of the following objects by shading the corresponding sides with matching colors or patterns:

20. Creating your 1st Orthographic Drawing
Step 1: Draw the front view – starting in lower left corner of the paper
Measure the length & height of the drawing and decide on the scale for the drawing
Draw light construction lines to frame the front view then make any other relevant measurements and draw the shape using the construction lines as a guide.
Have students color front, top, and side view…then demonstrate drawing front view on board.
Color in the front, top, and side view of the diagram above 23

21. Creating your 1st Orthographic Drawing
Step 2: Prepare to draw the top and side views
Draw construction lines extending upward and to the right from the front view (as shown below) 24

22. 25

23. Creating your 1st Orthographic Drawing
Step 5: Verify correctness and erase construction lines
Teacher 26

24. Orthographic Drawing Practice
Draw a multi-view drawing of the following block: 1. 2.

25. Orthographic Drawing Practice
Solution

26. Orthographic Drawing Practice
Solution

27. Orthographic Drawing Practice
Draw a multi-view drawing of the following block: 3. 4.

28. Orthographic Drawing Practice
Solution

29. Orthographic Drawing Practice
Solution

30. Orthographic Drawing Practice
Draw a multi-view drawing of the following block: 5.

31. Orthographic Drawing Practice
Solution

32. Dimensioning
All engineering drawings should indicate dimensions - the distances and locations on the actual object
Dimensions usually consist of a dimension line, capped by two arrowheads and broken in the middle for the measured distance
Two extension lines may extend from the edges of the object to show clearly where the dimension line begins and ends
Note: dimension and extension lines
should be drawn lighter than object lines

33. Dimensioning

34. Title Blocks
Title blocks are used to give essential information on technical drawings
Located on the lower-right side of the engineering drawing and typically include:
Name of the drafter
Title of drawing
Scale
Date

35. Final Orthographic Practice
Create orthographic drawings for the following blocks. Include a Title Block and dimensions.
Scale is 1: 12
1” = 12”

36. Do Now…
Complete the missing view of the object below.

37. Review Remember… Let’s review with worksheet problems.
Orthographic Drawings are drawn to scale
Draw Top, Front, and Right Side as follows:
Let’s review with worksheet problems.

38. Creating Isometric Drawings
Step 1 – Draw front corner, slanting lines at 30 degrees
Step 2 – Keeping the lines parallel to your initial corner sketch lines and using a ruler to maintain correct size, draw the front view shape
Step 3 – Complete drawing, ensuring lines stay parallel

39. Another way to create isometric drawings…
Step 1 – Draw front corner, slanting lines at 30 degrees
Step 2 – Lightly draw an isometric box that the entire shape will fit in
Step 3 – sketch details of the shape on the front, top, and side
Step 4 – Erase lines that are not needed

40. Practice
Create Isometric drawings of the following part:

41. Practice
Create Isometric drawings of the following part:

42. For Homework…