# Dimensioning Dimensioning Gateway To Technology®

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

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.

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

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)

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

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.

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.

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.

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

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)

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

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

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

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

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

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

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

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

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

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?”

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

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.

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

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

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

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

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.

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.

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

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

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

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.

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

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)

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.

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.

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

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.

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.

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

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.

…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.

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.

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.

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