1. Dimensioning Dimensioning Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimensioning

2. Why do we use Dimensions?
Dimensioning
Why do we use Dimensions?
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Engineers, designers, and engineering technologists need to know
Size
and
Location of all features
Size dimensions describe the size of each geometric feature.
With respect to linear dimensions, size dimensions are sometimes referred to as overall dimensions and will tell the viewer the overall width, height, and depth of an object.
Location dimensions show the location of each geometric feature within an object or view.
Location dimensions tell the viewer where edges occur inside an object view.

3. What is Dimensioning? Placing numbers (MEASUREMENTS) on a drawing
Those numbers show SIZE & LOCATION
SIZE shows how big or small a feature is
LOCATION explains exactly where something exists in a view
Remember, we draw three views: the front view, top view, and side view

4. How do we Dimension?
It is important to try to include enough dimensions on a drawing to adequately describe an object (but not too many)
It is also very important we locate those dimensions in the CORRECT place
Most dimensions should be drawn between views (between the front and top views or between the front and side views)

5. How to Dimension
We will need lines with arrows that show length or size of something on a view
We will need a spot for those arrows to point (beginning and ending spots)
We will need to place a measurement on our drawing within that arrow
We need to put all this information in the best possible (correct) location on our drawing

6. Dimension Completely Width Dimensioning Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Completely
Width
The students should notice the location of the dimensions and how the largest are on the top or outside and they become gradually smaller as you get closer to the object.

7. Dimension Completely Width Height Dimensioning Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Completely
Width
Height
Talk to the students about over-dimensioning and what is meant by over-dimensioning.

8. What “three” Dimensions?
Dimensioning
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
What “three” Dimensions?
Width
Height
Depth
Point out the location dimensions for the circle.
Center mark and centerline bisectors are needed to show where the center of a circle is.

9. Three types of LINES used…
There are mainly three types of lines used when drawing dimensions
EXTENSION LINES
DIMENSION LINES
LEADER LINES
Notice the explanations on the next slides

10. Extension Lines…
Extension lines are the lines that stick out from a corner or edge of a view
Look at the drawing again and pay close attention to the examples of extension lines that “extend” out from a corner but DO NOT TOUCH any construction line
This is where the “arrows” will point (touch)

11. Dimension Line “Types” again:
Dimensioning
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Line “Types” again:
Dimension Line
Extension Line
Dimension Line - Thin lines capped with arrowheads which may be broken along their length to provide space for the dimension numerals. Whenever possible try to center the dimension between the arrows.
Extension Line - Thin lines used to establish the extent of a dimension. Extension lines should not touch the object. Notice the space between the object line and the extension line, and between the center line and the extension line in the hole location dimension. Extension lines can be shared between individual dimension lines.
Leader Line - Lines that are thin and used to connect a specific note to a feature.
Point out the symbol for diameter.
Leader Line

12. Dimension Lines… Now, look at the lines with the arrows on each end
These lines are drawn from extension line to extension line
These “dimension lines” often have a number in the middle (the distance shown)
Notice the dimension lines in the next slide

13. Dimension Line “Types” again:
Dimensioning
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Line “Types” again:
Dimension Line
Extension Line
Dimension Line - Thin lines capped with arrowheads which may be broken along their length to provide space for the dimension numerals. Whenever possible try to center the dimension between the arrows.
Extension Line - Thin lines used to establish the extent of a dimension. Extension lines should not touch the object. Notice the space between the object line and the extension line, and between the center line and the extension line in the hole location dimension. Extension lines can be shared between individual dimension lines.
Leader Line - Lines that are thin and used to connect a specific note to a feature.
Point out the symbol for diameter.
Leader Line

14. Leader Lines…
Leader lines are not used as frequently, but they are still important
Notice where it points
Notice what it is showing
Look at the slide again and pay close attention to how each line is used

15. Dimension Line “Types” again:
Dimensioning
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Dimension Line “Types” again:
Dimension Line
Extension Line
Dimension Line - Thin lines capped with arrowheads which may be broken along their length to provide space for the dimension numerals. Whenever possible try to center the dimension between the arrows.
Extension Line - Thin lines used to establish the extent of a dimension. Extension lines should not touch the object. Notice the space between the object line and the extension line, and between the center line and the extension line in the hole location dimension. Extension lines can be shared between individual dimension lines.
Leader Line - Lines that are thin and used to connect a specific note to a feature.
Point out the symbol for diameter.
Leader Line

16. Next: Dimensioning Guidelines (Rules)
Incorrect dimensions will be shown in RED
Correct dimensions will be shown in GREEN

17. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
1) Dimensions should NOT be duplicated, nor should the same information be given in two different ways.
Incorrect

18. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
1) Dimensions should NOT be duplicated, nor should the same information be given in two different ways.
References:
Pg 337 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 109 Fundamentals of Modern Drafting by Paul Wallach
Pg 425 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 701 Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe
Correct

19. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
2) Dimensions should be attached to the view that best shows the contour (curve, shape) of the feature to be dimensioned.
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 405 & 425 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 698, 700, Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe
It should be noted that the 2.00 inch dimension would be appropriately located if placed on the top view, but the front view is preferred because it is supposed to provide the most information about an object’s geometry.
Incorrect

20. Take a look at this rule again…
2) Dimensions should be attached to the view that best shows the contour of the feature to be dimensioned. So, look at the drawing again (next slide). According to this rule, which view SHOULD those red dimensions be “attached to?”

21. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
2) Dimensions should be attached to the view that best shows the contour (curve, shape) of the feature to be dimensioned.
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 405 & 425 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 698, 700, Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe
It should be noted that the 2.00 inch dimension would be appropriately located if placed on the top view, but the front view is preferred because it is supposed to provide the most information about an object’s geometry.
Incorrect

22. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
2) Dimensions should be attached to the view that best shows the contour of the feature to be dimensioned.
Correct
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 405 & 425 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 698, 700, Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe
It should be noted that the 2.00 inch dimension would be appropriately located if placed on the top view, but the front view is preferred because it is supposed to provide the most information about an object’s geometry.

23. Incorrect 3) Don’t attach dimensions to hidden lines.
Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
3) Don’t attach dimensions to hidden lines.
Incorrect
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 134 Fundamentals of Modern Drafting by Paul Wallach
Pg 426 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 703 Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe

24. 3) Don’t attach dimensions to hidden lines.
Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
3) Don’t attach dimensions to hidden lines.
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 134 Fundamentals of Modern Drafting by Paul Wallach
Pg 426 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 703 Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe

25. Incorrect 4) Don’t dimension over or through an object.
Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
4) Don’t dimension over or through an object.
Incorrect
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 394, 404, 426 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 692 Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe

26. 4) Don’t dimension over or through an object. (not inside any view)
Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
4) Don’t dimension over or through an object. (not inside any view)
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 394, 404, 426 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 692 Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe

27. Incorrect 5) Put dimensions between adjacent views.
Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
5) Put dimensions between adjacent views.
Incorrect
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 108 Fundamentals of Modern Drafting by Paul Wallach
Pg 426 Technical Drawing 9th Edition by Frederick Giesecke, et. al.

28. 5) Put dimensions between adjacent views.
Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
5) Put dimensions between adjacent views.
References:
Pg 342 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 108 Fundamentals of Modern Drafting by Paul Wallach
Pg 426 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Notice this dimension is not between the views; HOWEVER, this is a better placement than dimensioning to the hidden line in the right side view.

29. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
6) A circle is dimensioned by its diameter. An arc is dimensioned by its radius.
References:
Pg , Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 131, Fundamentals of Modern Drafting by Paul Wallach
Pg , , 427 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg , Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe

30. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
7) Holes are located by their centerlines. These lines are often drawn long enough to be used as extension lines.
References:
Pg 44, 340 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg , 426 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe

31. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
8) Holes should be located and sized in the view that shows them as a circle.
Incorrect
References:
Pg 351 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 109 Fundamentals of Modern Drafting by Paul Wallach
Pg 411, 427 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 693 Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe

32. Dimensioning Guidelines
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
8) Holes should be located and sized in the view that shows them as a circle.
Correct
References:
Pg 351 Engineering Drawing and Design 3rd Edition by David Madsen, et. al.
Pg 109 Fundamentals of Modern Drafting by Paul Wallach
Pg 411, 427 Technical Drawing 9th Edition by Frederick Giesecke, et. al.
Pg 693 Technical Graphics Communication 3rd Edition by Gary Bertoline & Eric Wiebe
Note: The top view was removed because it is not needed to completely communicate the object’s geometry.

33. Numbers 3 and 4 Read question 3
Your instructor may explain this more (Raise your hand if you have a question)
Peek at the graph paper on the back of your worksheet for clarification
Look at question 4 (the reverse)
Take two or three minutes to answer question 3 and question 4

34. Missing Dimensions
Look at the next slide and try to figure out where there are some missing dimensions
Don’t forget the arrows on both ends of your dimension lines when we draw them
Don’t write them on your paper yet
Look at the three-view drawing and try to notice (to yourself) where a dimension is missing (#5 on the back of your sheet)

35. Can you locate where there are three Missing Dimensions?
Dimensioning
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Can you locate where there are three Missing Dimensions?
¼ in. scale or 4 squares = 1 in.
Give students time to complete this in Activity Dimensioning before going on to the next slide.

36. Here They Are Dimensioning Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Here They Are
Notice that the dimension value is all the same, but the dimension is measuring the size of different features. This is NOT duplicating a dimension. Often you will have the same value, but you will dimension different features.

37. Draw them….
Draw those three dimensions on your paper when that slide is repeated (next)
The next slide will show the missing dimensions again
Do your best to put them on your drawing as neatly and correctly as possible
You will have to squeeze one of them between two other dimensions

38. Here They Are Dimensioning Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Here They Are
Notice that the dimension value is all the same, but the dimension is measuring the size of different features. This is NOT duplicating a dimension. Often you will have the same value, but you will dimension different features.

39. Practice Dimensioning…
Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Practice Dimensioning…
¼ in. scale or 4 squares = 1 in.
Give students time to complete this in Activity Dimensioning before going on to the next slide.
Tell students that it is not good dimensioning practice to dimension to a hidden line.
A future presentation will describe the guidelines associated with dimensioning.

40. Check Your Answers Dimensioning Gateway To Technology®
Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques
Check Your Answers
Orthographic graph paper is removed to better show dimensions.

41. Directions for next two pages:
Next, for each isometric sketch on the next few pages you will need to create orthographic drawings (front view, top view, and side view)
…and dimension them.
You will complete three examples.

42. …more…
Make sure you place the front view in the lower left corner, the top view directly above the front view in the upper left corner, and the right side view to the right of the front view in the lower right corner.

43. Begin. Line up your sketches both horizontally and vertically.
Add all of the dimensions necessary using the scale 1 square = ¼ in.
Your dimension lines should have arrows at the end, and the extension lines you draw should not touch your object lines.

44. Homework?
Work on these orthographic drawings for the remainder of class.
Unless your instructor tells you differently, anything you do not finish is homework.
DO NOT LOSE THIS ASSIGNMENT.
Do the best you can and good luck.