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

Dimensioning Why 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.

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.

Dimension Completely Width Height Depth Dimensioning Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques Dimension Completely 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.

Dimension Line “Types” Dimensioning Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques Dimension Line “Types” 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) Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques Next: Dimensioning Guidelines (Rules) There are dozens of rules, dos and don’ts, and guidelines associated with dimensioning. The purpose of this presentation is to introduce those guidelines that are most critical. These 8 rules have been taken from the IED curriculum as the guidelines that we most want middle school students to recognize. You may use the IED presentation on Dimension Guidelines if you want to include the 16 guidelines that they discuss.

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, 701-703 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, 701-703 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) Whenever possible, avoid dimensioning to hidden lines. Dimensioning Guidelines Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques 3) Whenever possible, avoid dimensioning 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) Whenever possible, avoid dimensioning to hidden lines. Dimensioning Guidelines Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques 3) Whenever possible, avoid dimensioning 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) Avoid dimensioning over or through the object. Dimensioning Guidelines Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques 4) Avoid dimensioning over or through the 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) Avoid dimensioning over or through the object. Dimensioning Guidelines Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques 4) Avoid dimensioning over or through the object. 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

Dimensioning Guidelines Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques 5) Whenever possible, place 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) Whenever possible, place dimensions between adjacent views. Dimensioning Guidelines Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques 5) Whenever possible, place 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 and an arc is dimensioned by its radius. References: Pg 344-345, 347-349 Engineering Drawing and Design 3rd Edition by David Madsen, et. al. Pg 131, 138-139 Fundamentals of Modern Drafting by Paul Wallach Pg 402-403, 410-411, 427 Technical Drawing 9th Edition by Frederick Giesecke, et. al. Pg 687-688, 695-696 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, which may be extended and used as extension lines. References: Pg 44, 340 Engineering Drawing and Design 3rd Edition by David Madsen, et. al. Pg 393-394, 426 Technical Drawing 9th Edition by Frederick Giesecke, et. al. Pg 690-691 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.

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.

Can you locate where there are Missing Dimensions? Dimensioning Gateway To Technology® Unit 1 – Lesson 1.4 – Sketching and Dimensioning Techniques Can you locate where there are Missing Dimensions? ¼ in. scale or 4 squares = 1 in. Give students time to complete this in Activity 1.4.5 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.

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 1.4.5 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.

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.

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.