Basic Drafting Techniques Section 4.1 Getting Ready to Draw Section 4.2 Creating a Drawing

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4 Basic Drafting Techniques Section 4.1 Getting Ready to Draw Section 4.2 Creating a Drawing

Chapter Objectives • Prepare a drawing sheet for a technical drawing. • Use basic drafting tools and equipment. • Produce a ﬁ nished technical drawing using board-drafting techniques. • Use standard layouts to create and set up a drawing ﬁ le on a CAD system. • Create basic geometry and produce a technical drawing using CAD commands.

Checkmate Each type of piece you need for a chess game must go through an entire design process. How many pieces would you need to design for a complete chess set?

88 Todd France/Corbis Drafting Career

Michael Graves, Product Designer

When you think of a chess set, do you think of mechanical drawing and illustrations? Michael Graves and his team of designers understand the connection. Graves is a world-renowned architect and designer who creates the whimsically designed games, dog food dishes, toasters, teapots, and housewares that are sold in Target stores nationwide.

The Graves design team uses CAD software to visualize and design each product. The team presents paper drawings with just a few models. Then 3D drawings are completed and used to manufacture the large assembly machines that stamp out the forms or create the molds for items like toasters and cappuc- cino makers. Academic Skills and Abilities • Math • Computer science • Information systems • Computer programming • Business management skills • Verbal and written communication skills • Organizing and planning skills Career Pathways In addition to a bachelor’s degree in industrial design, commercial and industrial designers usually receive on-the-job training and normally need one to three years of training before they advance to higher level positions. Some experienced designers open their own design ﬁ rms.

Go to glencoe.com for this book’s OLC to learn more about Michael Graves Design.

89 4.1 Getting Ready to Draw

Connect Board and CAD drafters must select and gather the appropriate tools and prepare their work areas. As you read this section, take notes on preparing a drawing sheet. Content Vocabulary • sheet layout • revision • drawing • paper space • layer • reference history block templates • limits zones • application • model space blocks Academic Vocabulary Learning these words while you read this section will also help you in your other subjects and tests. • appropriate Graphic Organizer On a chart like the one below, list the tools you will need to create a board-based drawing and a CAD drawing.

Board-Based Drafting tools CAD tools Go to glencoe.com for this book’s OLC for a downloadable version of this graphic organizer

Academic Standards

English Language Arts NCTE National Council of Teachers of English Use written language to communicate eﬀ ectively (NCTE 4) NCTM National Council Conduct research and gather, evaluate, and synthesize data to communicate discoveries (NCTE 7) of Teachers of Mathematics Mathematics ADDA American Design Drafting Association Number and Operations Compute ﬂ uently and make reasonable estimates (NCTM) ANSI American National Problem Solving Solve problems that arise in mathematics and other contexts (NCTM) Standards Institute ASME American Society of Mechanical Engineers Industry Standards

ADDA Section 1

Functional/Simpliﬁ ed Drafting (ASME Y14.3M, ANSI Y14.4, ANSI Y14.6)

90 Chapter 4 Basic Drafting Techniques Preparing the Drawing Hold Head of Ted Mishima Ted T-Square in Sheet contact with What are the steps in preparing a drawing edge of sheet? board Align edge Proper sheet preparation is an impor- of paper tant part of the drafting process. Prepar- with blade of ing the drawing sheet includes choosing an T-Square appropriate size and type of drawing sheet, fastening it to the drawing board, and laying out the borders and title block. Choosing the Drawing Sheet The type of drawing sheet you select Approx. 1” depends on how the fi nal drawing will be used. For example, drawing paper is appropriate for short-term use, while polyester fi lm is better for long-term use. The size of the sheet is determined by the size and complexity of the drawing. It is often useful to make a freehand sketch of the views and notes before proceeding to do the fi nal instrument drawing. Except in rare cases, standard drawing-sheet sizes should be used. Fastening the Drawing Sheet to the Board Figure 4-1 To fasten the drawing sheet to the board, fi rst By attaching the drawing sheet to the align the sheet with the T-square blade. board, you have the freedom to move the T- square and triangles freely over the whole sheet. The sheet may be held in place on the board in several ways. Some drafters put draft- head of the T-square against the edge of the ing tape across the corners of the sheet and, board. Then fasten each corner of the sheet if needed, at other places. Others use small, with drafting tape. precut, circular pieces of tape, called dot tape. Neither of these two methods will damage the Sheet Layout corners or the edges of the sheet. They also Sheet Layout is the process of placing the can be used on composition boards or other border and title block on the drawing sheet. boards with hard surfaces. U.S. Customary drawing sheet layouts (inch To fasten the paper or other drawing sheet, sizes) are designed and recommended by the place it on the drawing board with the left American Society of Mechanical Engineers edge 1″ (25 mm) or so away from the left edge (ASME). Metric sheet layouts (millimeter of the board, as shown in Figure 4-1. (Left- sizes) are designed and recommended by the handed students should work from the right International Organization for Standardiza- edge.) Put the lower edge of the sheet at least tion (ISO). Margins for the borders on metric 4″ (100 mm) up from the bottom of the board sheets are somewhat uniform in size, while so you can work on it comfortably. Then those on U.S. Customary sheets vary. How- line up the sheet with the T-square blade, as ever, the sheet sizes and layouts prepared shown in Figure 4-1. Hold the sheet in posi- by ASME and ISO are simply recommenda- tion. Move the T-square down, keeping the tions. They may vary according to the user’s

Section 4.1 Getting Ready to Draw 91 requirements. However, all drawing sheets what, when, and where.” The revision should have a border and title block. Also, it history block specifi es revision dates and is strongly recommended that the location of related information. The application various elements of the title block be placed blocks are optional. They provide columns as specifi ed by ASME or ISO. In many indus- for purposes such as listing specifi c informa- tries, borders and title blocks are printed on tion used to relate a given drawing to other the drawing sheets and the drafter simply fi lls drawings in a set. in the blanks in the title block and prepares the drawing within the borderlines. The layout recommendations of both ASME and ISO are shown in Figure 4-2. ASME actu- Identify What do the acronyms ASME and ally lists six standard sizes for drawing sheets ISO stand for? plus special roll sizes, and ISO lists fi ve standard sizes plus various elongated sizes. The information in Figure 4-2 is limited to the Sheet Layout: U.S. Customary most common sheet sizes used in educational Table 4-1 gives specifi c sizes for standard programs. sheets. For example, an A-size sheet placed Reference zones given in the margins in the horizontal position is 8.50 vertically are used to locate specifi c information on and 11.00 horizontally (8.50 11.00). When the drawing. The title block provides basic placed in the vertical position, it is 11.00 ver- information about the drawing— the “who, tically and 8.50 horizontally (11.00 8.50).

MARGIN DRAWING NUMBER BLOCK

I A AND A4 SIZE REFERENCE ZONES (HORIZONTAL) D REVISION 2 I HISTORY F REVISION APPLICATION BLOCK BLOCK HISTORY BLOCK C SEE TABLE 4-1 E B AND A3 SIZE

B B A AND A4 SIZE TITLE BLOCK (VERTICAL) D C AND A2 SIZE

A A APPLICATION BLOCK 6 5 432I TITLE BLOCK

B MICROFILM CENTERING ARROW TITLE BLOCK

REVISION STATUS

A A TITLE BLOCK

8 765 432I

GENERAL NOTE: DIMENSIONS SHOWN ARE RECOMMENDED AND MAY BE VARIED TO ACCOMMODATE THE USER'S REQUIREMENTS.

Figure 4-2 Decimal-inch and metric drawing sheet layout.

92 Chapter 4 Basic Drafting Techniques Decimal-Inch Sizes Table 4-1 Size Vertical Horizontal Margin Sizes Decimal-Inch and Metric Designation Sheet Size Sheet Size Horizontal Vertical Drawing Sheets

A (Horizontal) 8.50 11.00 .38 .25 A (Vertical) 11.00 8.50 .25 .38

B (Horizontal) 11.00 17.00 .38 .62 C (Horizontal) 17.00 22.00 .75 .50

Metric Sizes A4 (Horizontal) 210 mm 297 mm 10 10

A4 (Vertical) 297 mm 210 mm 10 10 A3 297 mm 420 mm 10 10

A2 420 mm 594 mm 10 10

B- and C-size sheets are generally not used in be eliminated on drawings that are not the vertical position. government-related. Figure 4-3 shows a recommended lay- Since the trim sizes recommended by out for the title block, which should be ASME and ISO are in almost universal use in placed in the lower right-hand corner industry, they are also useful sizes for draft- of the drawing. Since it is only recom- ing courses. Most of the drawing problems mended, it can be altered in both size and throughout this book are planned for A-, B-, content. For example, “cage code” is a ref- A4-, or A3-size sheets. However, to reduce the erence number generally used on drawings amount of time and space required to draw prepared for government contracts. It can the title blocks, you may use the modiﬁ ed

3.90

2.80 .40

COMPANY NAME AND ADDRESS INFORMATION RELATED TO PREPARATION OF TITLE DRAWING INCLUDES 2.00 NAME OF DRAFTER, ENGINEER, CHECKER, 1.40 ISSUE DATE, ETC. SIZE CAGE CODE DWG NO. REV .60 SCALE SHEET .30

1.80

3.30

4.30

6.30 GENERAL NOTE: DIMENSIONS SHOWN ARE RECOMMENDED AND MAY BE VARIED TO ACCOMMODATE THE USER'S REQUIREMENTS.

Figure 4-3 Recommended title block for A, B, and C drawing sheet sized (decimal inch)

Section 4.1 Getting Ready to Draw 93 version shown in Figure 4-4 for U.S. Cus- Larger sheets are generally used only in the tomary drawings. Alternate layouts are shown horizontal position. in Figure 4-5. Your instructor may assign one Figure 4-6 shows a recommended layout for of these or one that he or she has designed. the metric title block. It is essentially the same as the decimal-inch title block. The difference is Sheet Layout: Metric in the units of measure used to lay it out. Like In Table 4-1, you will see that the smallest the U.S. Customary recommendations, metric metric-size sheet is A4. Placed in a horizon- recommendations may be altered to accommo- tal position, it is 210 mm vertically and 297 date the user’s speciﬁ c requirements. mm horizontally (210 297). When placed Figures 4-7 and 4-8 show recommended in a vertical position, it is 297 mm vertically A4 and A3 drawing-sheet layouts with borders and 210 mm horizontally (297 210). The and title blocks. These have been modiﬁ ed from A4-size sheet may be used in either position. the recommended ISO standard metric sheet

.50

8.50 5 X .12 OR 17.00

NAME OF SCHOOL DRAWING NAME DRAWN BY DWG NO. .60 LOCATION SCALE DATE APPROVED BY

.30

.30 3.00 3.00 .80

11.00

Figure 4-4 Suggested sheet layout for an A- or B-size sheet.

B ( 11x17 ) or A3 ( 297 mm x 420 mm ) Drawing Sheet Horizontal Position

B ( 11x17 ) or A3 ( 297 mm x 420 mm ) Figure 4-5 Drawing Sheet Vertical Position Alternate layouts.

A ( 8.50 x 11.00 ) or A4 ( 210 mm x 297 mm ) Drawing Sheet Horizontal Position

94 Chapter 4 Basic Drafting Techniques layouts. The sheet sizes are ISO standard; the layouts have been modiﬁ ed to save time and space in preparing the sheets. Your instructor Identify Where is the title block placed on a may assign one of these or one that he or she drawing? has designed. Figure 4-8 shows alternate title block layouts for decimal-inch and metric drawing sheets.

70 10

COMPANY NAME AND ADDRESS INFORMATION RELATED TO PREPARATION OF TITLE DRAWING INCLUDES 54 NAME OF DRAFTER, ENGINEER, CHECKER, 36 ISSUE DATE, ETC. SIZE CAGE CODE DWG NO. REV 16 SCALE SHEET 6

45 80 Figure 4-6 110 Recommended title 160 block for A2, A3, and A4 drawing-sheet sizes (metric)

Figure 4-7 210 METRIC Recommended sheet 5 X 3 layout for an A4- or NAME OF SCHOOL DRAWING NAME DRAWN BY DWG NO. 15 LOCATION SCALE DATE APPROVED BY A3-size sheet 8

8 75 75 20 8

297

Decimal-inch METRIC .12 TYPICAL 3mm TYPICAL Figure 4-8 NAME OF SCHOOL NAME OF SCHOOL .60 15 LOCATION LOCATION Alternate title block

DRAWING NAME DRAWING NAME layouts for decimal-inch .60 15 SCALE DATE 2.10 SCALE DATE 53 (A- and B-size) and metric DWN BY DWG NO. DWN BY DWG NO. .60 15 (A3- and A-4 size) sheets APP BY APP BY

.30 8

.80 .30 20 .30

3.30 85

Section 4.1 Getting Ready to Draw 95 Getting Ready to Create Creating a New Drawing As with board drafting, you must plan care- a CAD Drawing fully before you begin to draw in CAD. Even How does preparing a CAD drawing differ though you will be drawing at full size, you from preparing a drawing sheet? must select a sheet size—and a scale—for the printed drawing before you begin. Techniques for creating a technical drawing The fi rst step in preparing a drawing fi le is to using CAD differ greatly from those used in open a new drawing in AutoCAD. Some versions board drafting. One of the biggest differences of AutoCAD contain drawing templates for is that CAD drawings are drawn at full scale, the various ASME sheet sizes (see Figure 4-9). whether the object being drawn is a micro- A drawing template is a standard drawing setup chip or a municipal parking lot. that conforms to ASME or ISO standards. For Obviously, you cannot print a drawing of this example, we will use AutoCAD’s acad.dwt a parking lot at full size. Therefore, you must template. print the drawing at a scale that allows it to 1. Enter the NEW command to create a fi t on the selected drawing sheet. If you set new drawing. For this exercise, either the drawing up properly before you begin to type NEW or pick New from the File pull- draw, you can draw at full size and print at the down menu. (Do not use the button on appropriate scale on the drawing sheet. the Standard toolbar.) In other ways, drafting using a CAD system 2. In the Select Template dialog box, select is similar to board drafting. You must under- the acad.dwt template. stand drafting concepts before you can create an acceptable CAD drawing. Except where Notice the MODEL button at the bottom of noted, all of the drafting principles discussed the screen, below the border and title block. in this and other chapters apply equally to AutoCAD has two drawing spaces. Model CAD and board drafting. space is a working space, where you will This part of the chapter is designed to be do most of your drawing. Layout, or paper “done,” rather than just read. Ideally, you space, allows you to position your drawing should have access to a CAD workstation, so on the specifi ed drawing sheet. you can try the techniques as you read about In most versions of AutoCAD, you will also them. If this is not possible, read the contents see tabs at the bottom of the drawing area. If thoroughly, and then have the book with you the tabs are not present, right-click the Model the next time you have access to CAD. or Paper button on the status bar and choose

REVISIONS

ZONE REV DESCRIPTION DATE APPROVED

Figure 4-9 Some versions of AutoCAD provide templates for standard ISO and ASME borders and title blocks. This is a layout for a B-size sheet.

SIZE FSCM NO. DWG NO. REV

SCALE SHEET

96 Chapter 4 Basic Drafting Techniques to show the Model and Layout tabs. Remem- ber to choose the Model tab whenever you are actually creating or editing a drawing. Choose the appropriate layout tab to view or work with the drawing in paper space. Zooming Setting the Drawing Units CAD programs allow you to “zoom out” to see all of a drawing, or “zoom Drawings based on the acad.dwt template in” to see part of it in a magnifi ed open automatically in model space. Be sure form that is easier to see and work that the Model tab is the active tab. Then con- with. After you have set the draw- tinue to set up the drawing fi le. The next task ing limits and set the snap and grid, is to specify the drawing units. zoom out to see the whole drawing. unit In AutoCAD, the term is purposely To do so, enter the ZOOM command vague. AutoCAD ensures that 1 unit 1 unit. (or press the “z” key and Enter) and It is up to you to determine whether the unit then type the word All. The entire stands for millimeters, inches, miles, or, for drawing space appears in the draw- some engineering applications, even hours or ing area. other nonlinear units. Therefore, before you Later, if you want to see a detail of begin drawing, you must specify what the part of the drawing, enter the ZOOM units will be. command and then specify the part To set the units in a drawing, enter the you want to see by using the mouse UNITS command. AutoCAD presents a dialog to create a window, or rectangle, box that lets you choose from architectural, around that part. ZOOM All always decimal, engineering, fractional, or scientifi c takes you back to a view of the entire units for both length and angle measure- drawing. ments. For the drawings in this textbook, you should choose decimal units unless directed otherwise. Selecting decimal units in AutoCAD does 17 11. To do this, use the LIMITS com- not limit you to working in decimal inches. mand. This command works by specifying By choosing decimal units, you are setting the lower left and upper right corners of the up the drawing correctly for both ASME and drawing area. ISO standards. Only the precision differs. For Enter the LIMITS command, and then look ASME, select a length precision of two deci- at the Command line at the lower left corner mal places (0.00). For ISO or metric, select a of the screen. It shows that the lower left cor- length precision of one decimal place (0.0). ner is currently set to 0.00,0.00. This means For both standards, set angle precision to no that the lower left corner of the drawing is decimal places (0), unless directed otherwise. set at 0.00 inches horizontally and vertically. In this case, choose precisions. In general, you should leave the values at 0.00,0.00. Press Enter to continue. For an A- Setting the Drawing Limits size sheet (without scaling), type 11.00,8.50 Next, set the limits, or physical size of and press Enter. Do not type a space between the drawing area, to correspond to the draw- the comma and the 8.50. Then enter the ing sheet size you will use for paper space. ZOOM command and the All option to view The paper-space layout does not affect the entire drawing area. model space, so you have to set the limits separately. Limits for Printing at Full Size This example will use an A-size sheet. If Describe What function does the LIMITS your drawing will fi t on the sheet without command perform? scaling, you should set the drawing size to

Section 4.1 Getting Ready to Draw 97 Sheet SizeDrawing Model Space 10 – 32 UNC – 2B Ø.50 ASME B1.1 Scale Limits

ASME A 1:1 11.00 8.50 .50 1:2 22.00 17.00 Ø2.00 1:4 44.00 34.00 Ø1.10 ASME B 1:1 17.00 11.00 1:2 34.00 22.00 1:4 68.00 44.00 R.10 ASME C 1:1 17.00 22.00 1:2 34.00 44.00 .20 1:4 68.00 88.00 .05 X 45° 1.50 CHAMFER ISO A4 1:1 210 mm 297 mm 1:2 420 mm 594 mm A 1:4 840 mm 1188 mm ISO A3 1:1 297 mm 420 mm 1:2 594 mm 840 mm 1:4 1188 mm 1680 mm ISO A2 1:1 420 mm 594 mm 1:2 840 mm 1188 mm 1:4 1680 mm 2376 mm

Table 4-2 Drawing limits B

Figure 4-10 Limits for Printing a Scaled By placing dimensions on a separate layer, you can control whether the dimensions display. In Drawing (A), the dimension layer is displayed. In (B), it has If you plan to scale the drawing to ﬁ t on the been frozen, so it does not show on the screen. If drawing sheet, you should set the model space you print the drawing with the dimension layer limits accordingly. For example, suppose you frozen, the layer will not print. are working with a B-size sheet, and you plan to print the drawing at a scale of 1:2. In other words, your full-size drawing will be twice as big as it will appear on the printed sheet. should be associated with them. Some com- Therefore, your model-space limits should be panies even use their own drawing templates twice the size of the B-size sheet, or 34 22. in which these layers have already been set Table 4-2 shows common drawing limits for up. For instructional purposes, this textbook drawings of different sizes and scales. will use a generic set of layers. These layers are shown in Table 4-3. Working with Layers All CAD programs, including AutoCAD, Creating a New Layer have a system of layers that gives the CAD To set up new layers in a drawing, enter the operator much greater control over a draw- LAYER command. Look closely at the contents ing. A layer is similar to a transparent paper of the dialog box. The 0 layer is the default overlay. By setting up a layer for dimensions, layer. Notice that several properties are listed for example, the CAD operator can control for each layer, including: whether dimensions are displayed by turn- • layer name ing the layer on and off, or by “freezing” and • on or off “thawing” it, as shown in Figure 4-10. • frozen or thawed Most companies have rules about what lay- • layer color ers to use, what to call them, and what colors • linetype

98 Chapter 4 Basic Drafting Techniques • line weight • plot style • plot (whether the layer plots when the drawing is printed)

Some versions of AutoCAD have additional properties, but those listed here are common to all versions. One of the standard layers used in this textbook is the Objects layer. This layer will be used for all of the visible lines of the part or object. Therefore, you already know that it will need to be a solid (or continuous) line that is .30 mm thick. To create a new layer named Objects, click the New button in the dialog box. A new layer appears in the window, and the layer name is highlighted. Type the word Objects in the layer name box.

Setting the Layer Color Figure 4-11 By default, new layers in AutoCAD are Colors can be used to distinguish visually the white. To set the color for a layer, pick White diﬀ erent elements in a CAD ﬁ le. or the color box for that layer. A color palette appears. To choose a different color, just pick a color and pick OK. However, because this is the Objects layer, leave it white. various colors, but set up a plot style to print Colors are used in CAD programs to help them all in black ink. Therefore, the color of the CAD operator distinguish among the a layer may or may not determine the color layers. See Figure 4-11. Some companies of the lines on that layer when the drawing is prefer to use white for all of their layers. Oth- printed. This is up to the individual drafter or ers establish company-wide standards. For company. example, they may declare that all electrical wiring will be on a blue layer named Electr. Selecting the Linetype These colors may or may not print, depend- AutoCAD gives new layers a continuing on the plot setting and the printer being ous linetype by default, so the Objects used. It is also possible to set up the layers in layer is already set up for the correct linetype. However, as you can see in Table 4-3, you will need to change it for some of the

NameColor Linetype Line Weight other layers. To do so, click the word Con- tinuous. A dialog box appears from which Objects White Continuous .30 mm you can change the linetype, but notice Dimensions Red Continuous .18 mm that you have no other choices. To load Hidden Lines White Hidden .18 mm other standard linetypes into the drawing, Centerlines Blue Center .18 mm pick the Load button. Another dialog box Notes Magenta Continuous .18 mm appears, allowing you to select from several ISO and ASME linetypes. To load the ISO Border White Continuous .18 mm standard dashed line, for example, choose Viewports Magenta Continuous .18 mm ISO02W100 ISO Dash and pick OK. The linetype becomes available for use in the draw- Table 4-3 ing. To choose the ASME standard dashed Layers for drafting problems line for hidden lines, scroll down to Hidden, pick it, and pick OK.

Section 4.1 Getting Ready to Draw 99 Figure 4-12 AutoCAD provides Loading Linetypes many standard line You will usually know in advance widths. which linetypes you will need for a drawing. It is more effi cient to load all of the needed lines at one time, before you close the dialog box. After adding each linetype, pick the Load button again to choose another one. Some versions of AutoCAD allow you to load all available linetypes by picking a Load All button. When you have fi nished, select the linetype you need Selecting the Line Width for the current layer. Then, select OK to return to the dialog box for The default line width in AutoCAD is 0. managing layers. This does not mean that the line does not print. However, the width of the line is not defi ned. You can and should defi ne the width of the lines on your drawings. To do so, pick Finishing Layer Setup the word Default in the Line Width column Now fi nish the layer setup for your draw- for the Objects layer. ing by creating the other layers listed in Table AutoCAD specifi es all of its line widths in 4-3. Be sure to give each layer the properties millimeters, as shown in Figure 4-12. Visible shown in the table. Then enter the Save com- lines in CAD are generally made at a width of mand to save the drawing fi le. Because of the .12, or .30 mm. Select .30 mm from the list settings chosen in this example, a suitable of line widths, and pick OK to apply it to the name for this fi le in Chapter 4 ASME B Full Objects layer. Scale, or use a name given by your instructor.

Section 4.1 Assessment Drafting Practice After You Read 3. On an 8½ 11 inch sheet of grid paper (inch or metric), sketch the borders and title block shown in Figure 4-6 or Self-Check 4-9 as assigned by your instructor. All 1. Describe the procedure for preparing a guidelines for lettering should be very drawing sheet for a technical drawing. thin and light; all other lines should be thick, sharp, and black. Academic Integration 4. If you have access to a computer with English Language Arts CAD software, follow the procedure you 2. Write a one-page essay explaining just read about to set up an ASME B-size the different parts of a sheet layout. drawing sheet that includes borders and Use Content Vocabulary terms and title block. Experiment with other sheet other information from this section to sizes. What are the dimensions of a explain each part of the layout. B-size sheet? Go to glencoe.com for this book’s OLC for help with this drafting practice.

100 Chapter 4 Basic Drafting Techniques 4.2 Creating a Drawing

Preview When preparing to draw, it is important to know how to use the basic tools. As you read this section, have your drawing tools or computers ready, so you can practice the various techniques. Content Vocabulary • inking • hidden lines • symmetrical • polyline • grid • alphabet of lines • centerlines • Ortho mode • radius • viewports • inclined lines • line weight • polar • snap coordinates Academic Vocabulary Learning this word while you read this section will also help you in your other subjects and tests. • diﬀ erentiate Graphic Organizer On a chart like the one below, list the basic ASME and ISO standards you will need to follow when drafting in CAD.

ASME Standards ISO Standards Go to glencoe.com for this book’s OLC for a downloadable version of this graphic organizer

Academic Standards

Science NCTE National Council of Teachers of English Science and technology in local, national, and global challenges (NSES) NCTM National Council of Teachers of Mathematics Mathematics NSES National Science Geometry Use visualization, spatial reasoning, and geometric modeling to solve problems (NCTM) Education Standards ADDA American Design English Language Arts Drafting Association ANSI American National Read texts to acquire new information. (NCTE) Standards Institute ASME American Society of Industry Standards Mechanical Engineers

ADDA Section 1

Functional/Simpliﬁ ed Drafting (ASME Y14.3M, ANSI Y14.4, ANSI Y14.6)

Section 4.2 Creating a Drawing 101 grade mark, being careful not to cut the lead. Ted Mishima Working with Drafting Leave about half an inch (13 mm) exposed. Pencils and Pens Then shape the lead to a long, conical point. Do this by rubbing the lead back and forth on When using drawing tools, why is it a sandpaper pad or on a long fi le, while turn- important to keep the drawing neat ing it slowly to form the point, as shown in and clean? Figure 4-13B and 4-13C. Some drafters pre- Techniques for using drafting pencils are fer the fl at point, or chisel point, shown in somewhat different from those for using tech- Figure 4-13D. Keep the sandpaper pad or fi le nical pens. Unlike pencil marks, ink must be at hand, so that you can sharpen the point allowed to dry before it can be touched. This often, as shown in Figure 4-14. affects the way the instrument should be held, Mechanical sharpeners have special drafter’s as well as the order in which the lines should cutters that remove the wood, as shown in be drawn. Figure 4-15. Special pointers are made for shaping the lead, as in Figure 4-16. Such Sharpening the Pencil To sharpen a wooden pencil, cut away the wood at a long slope, as shown in Figure 4-13A. Always sharpen the end opposite the

Figure 4-13 Figure 4-15 Sharpening the pencil properly is important. A drafter’s pencil sharpener cuts the wood, not the lead.

Figure 4-14 Rub the pencil on a sandpaper pad, turning it slowly, to achieve a conical point. BEFORE AFTER

Figure 4-16 The lead pointer allows a choice of point shapes.

102 Chapter 4 Basic Drafting Techniques uniform and keep the point from wearing down unevenly. Inking Techniques

Courtesy of Staedtler Inc. Inking is the process of creating technical drawings using technical pens. Techniques for inking are slightly different from those for drawing in pencil. Hand position and the order in which items are drawn are affected by the fact that ink, unlike pencil, must be allowed to dry to help avoid smudges. Figure 4-17 shows the correct position for drawing lines with a technical pen. Hold the technical pen in a nearly vertical position, perpendicular to the drawing surface, to get the most uniform line. Using Erasers Use soft erasers to clean soiled spots or light pencil marks from drawings. Keep in mind that regular ink erasers often contain grit. Figure 4-17 If you use these erasers at all, use them very carefully to keep from damaging the drawing The position of the technical pen is important surface. when drawing lines. The ink used on polyester drafting fi lm is waterproof. However, you can easily remove ink from the fi lm by rubbing it with a moist- devices may be hand-operated or electrically ened plastic eraser or by using an electric eras- powered. ing machine. Do not apply pressure when Mechanical pencils hold plain sticks of lead rubbing. The polyester fi lm does not absorb in a chuck that allows the exposed lead to be ink, so all ink dries on top of its highly fi n- extended various lengths. The lead for most ished surface. Remove ink from other surfaces, lead holders should be shaped in the same such as tracing vellum or illustration board, way as the lead in wooden pencils. Some refi ll with regular ink erasers or chemically treated pencils have a built-in sharpener that shapes ink erasers that absorb ink. Press lightly with the lead. strokes in the direction of the line to remove Never sharpen a pencil over the drawing ink caked on the surface. Too much pressure board. After you sharpen a pencil, wipe the lead damages the surface and makes it hard to with a cloth or a Styrofoam™-type “stab-it” to revise the drawing. remove the dust. Being careful in these ways When working on paper or cloth, erase will help keep the drawing clean and bright. lines along the direction of the work. On fi lm, always erase across the direction of the work. Techniques for Using a Drafting Always erase carefully to avoid marring the Pencil fi nish on the drawing sheet. Use an erasing Pencil lines must be clean and sharp; not shield to protect nearby lines and areas that fuzzy. They must be dark enough for the views you do not want to erase. to be seen when standard line widths are used. If you use too much pressure, you will groove the drawing surface. You can avoid this by using the correct grade of lead. Contrast Explain how using a drafting Rotate the pencil between your thumb and pencil diff ers from using a drafting pen. forefi nger as you draw to help make the line

Section 4.2 Creating a Drawing 103 THICK THICKNESS MAY VARY VISIBLE LINE TO SUIT SIZE OF DRAWING

THIN DASHES .12± ± HIDDEN LINE VISIBLE LINE HIDDEN LINE SPACES .03

CENTERLINE THIN EVENLY SPACED ON SECTION VIEW SECTION LINE

LONG DASHES THIN .75 TO 1.50±; CENTERLINE SHORT DASHES .06±

SECTION LINE CUTTING-PLANE LINE EXTENSION LINE EXTENSION LINE EXTENDS BEYOND IN TH DIMENSION LINE .12± LEADER Ø.375 LEADER THIN DIMENSION LINE

THIN 2.50 DIMENSION LINE UNBROKEN EXCEPT AT FIGURE; ARROWHEADS AT ENDS

UNBROKEN DIMENSION 1.62 2'–3 THIN LINE WITH FIGURE DIMENSION LINE ABOVE USED FOR CIVIL EXTENSION LINE AND ARCHITECTURAL DIMENSION LINE DRAWINGS

LONG DASHES .75 TO 1.50±; SHORT THICK DASHES .12±; CUTTING-PLANE LINE OR VIEWING-PLANE LINE SPACES .06±

SHORT-BREAK LINE THICK EQUAL DASHES .25± CUTTING-PLANE LINE OR VIEWING-PLANE LINE

THICK FREEHAND LINE FOR SHORT BREAKS SHORT-BREAK LINE

LONG-BREAK LINE THIN RULED LINES WITH FREEHAND ZIGZAGS LONG-BREAK LINE FOR LONG BREAKS

TRAVEL

THIN LONG DASHES .75 TO 1.50±; SHORT PHANTOM LINE DASHES .12± FOR ALTERNATE PHANTOM LINE POSITIONS, REPEATED DETAIL, ETC.

Figure 4-18 Alphabet of lines

104 Chapter 4 Basic Drafting Techniques other material. Always keep the point of the Alphabet of Lines lead a little distance away from the corner Ted Mishima Ted Why is the term “alphabet” used to between the guiding edge and the drawing describe the various lines used in drafting? surface, as shown in Figure 4-20. This will let you see where you are drawing the line. The different lines or line symbols used It will also help you avoid making a poor or on drawings form a kind of graphic alphabet smudged line. Be careful to keep the line par- commonly known as the alphabet of lines. allel to the guiding edge. The line symbols recommended by ASME are shown in Figure 4-18. Two line widths–thick and thin—are generally used. Drawings are easier to read when there is good contrast among different line widths. All lines must be uniformly sharp and black.

Explain Why does the alphabet of lines utilize two diﬀ erent line widths?

Techniques for Drawing Lines Why does line drawing require special instruments?

The sections that follow discuss basic drawing techniques. Additional, more complex techniques will be presented in later chapters. Figure 4-19 Horizontal Lines Drawing a horizontal line. To draw a horizontal line, use the upper edge of the T-square blade as a guide. With your left hand, place the head of the T-square in contact with the left edge of the board. Keeping the head in contact, move the T- GUIDE (T-SQUARE 90° square to the place you want to draw the line. OR TRIANGLE) Slide your left hand along the blade to hold SPACE TILT PENCIL it fi rmly against the drawing sheet. Hold the SLIGHTLY FOR pencil about 1" (25 mm) from its point. Slant EXTREME ACCURACY it in the direction in which you are drawing the line. (This direction should be left to right 60° TO 75° ON PAPER 55° TO 65° for right-handers and right to left for left- OR CLOTH ON FILM handers.) While drawing the line, rotate the pencil slowly and slide your little fi nger along POSITION OF PENCIL the blade of the T-square, as shown in Figure VIEWED FROM THE FRONT 4-19. This will give you more control over the pencil. Figure 4-20 On fi lm, keep the pencil at the same angle To ensure accurate drawing, position the pencil (55° to 65°) all along the line. You must also as shown here. use less pressure on fi lm than on paper or

Section 4.2 Creating a Drawing 105 Vertical Lines Ted Mishima Use a triangle and a T-square to draw vertical lines, as shown in Figure 4-21. Place the head of the T-square in contact with the left edge of the board. Keeping the T-square in contact, move it to a position below the start of the vertical line. Place a triangle against the T-square blade. Move the triangle to where you want to begin the line. Keeping the vertical edge of the triangle toward the left, draw upward. Slant the pencil in the direction in which you are drawing the line. Be sure to keep this angle the same when you are drawing on ﬁ lm. Keep the point of the lead far enough out from the guiding edge so you can Figure 4-21 see where you are drawing the line. Be careful Drawing a vertical line to keep the line parallel to the guiding edge. Inclined Lines Inclined lines are lines drawn at an angle that is neither horizontal nor vertical.

Decimal Degrees Degrees convert directly to It is becoming a more common practice to the same number of decimal degrees. Min- specify angles in decimal degrees rather than utes will be divided by 60 minutes per degree degrees, minutes, and seconds. Convert to arrive at the decimal degree, and seconds the following measurements into decimal will be divided by 3600 seconds per degree to degrees. arrive at the decimal degree. Decimal Degree Equivalent Example: Degrees, Minutes Decimal Degrees Convert 25°30 36 to decimal degrees. and Seconds 25° 25.00 degrees 0°45 30 .50 degrees 0°014 (30 minutes / 60 minutes per degree .50) 25°3036 36 .01 degrees (36 seconds / 3600 seconds per degree 01) 25°030 25.51 degrees

Academic Standards For math help, go to the Math Mathematics Appendix located at the back of this book. Select, apply, and translate among mathematical representations to solve problems. (NCTM)

106 Chapter 4 Basic Drafting Techniques They are drawn using triangles, a protractor, Lines Inclined at 15° Increments or a drafting machine. The 45° and 30-60° triangles, alone or 30°, 45°, and 60° Lines together and combined with a T-square, can be used to draw angles increasing by 15° from Angles are measured in degrees, min- the horizontal or vertical line. Some ways of utes, and seconds. You can draw lines placing the triangles to draw angles of 15° and at 30°, 45°, or 60° angles from the hori- 75° are shown in Figure 4-24. zontal or vertical by using the triangles. Lines inclined at 30° and 60° are drawn with the 30°-60° triangle held against the T-square blade, as shown in Figure 4-22 90° 8 ANGLES AT 90° 90° or against a horizontal straightedge. The 45° 45° = 360° 30°-60° triangle can also be used to lay off 90° equal angles, 6 at 60° or 12 at 30°, about a center point. To draw lines inclined at 45° from horizontal or vertical lines, hold the triangle AB C against the T-square blade, as shown in Figure 4-23, or against a horizontal straightedge. The 45° triangle can also be used to lay off eight equal angles of 45° Figure 4-23 about a center point. The 45° triangle has angles of 45° and 90°.

60° 6 ANGLES AT ° 15° 15 60° = 360° ° 60° 75° 75 75° 75° 15° 15° ° 15° 15

75° 75° 75° ° ° 15° 75 15 15°

AB CD

° ° 90° 15° 15 60 90° 60° 75° 75° 30° 30° ° 75° 75 30° 30° 30° 60° 15° 15° 90° 15° ° 60° 90° 15 75° 75° 12 ANGLES AT 30° = 360°

CD AB

Figure 4-22 Figure 4-24 The 30°-60° triangle has angles of 30°, 60°, Drawing lines at 15° and 75° using the two and 90°. triangles

Section 4.2 Creating a Drawing 107 Techniques for Special Lines that are made up of short dashes, as shown in Figure 4-25. Notice in Figure 4-25A that and Surfaces the ﬁ rst dash of a hidden line touches the line To describe an object fully, you must show where it starts. If a hidden line is a continua- every feature in each view, whether or not it tion of a visible line, space is left between the can ordinarily be seen. You must also include visible line and the ﬁ rst dash of the hidden line other lines that are not actually part of the (see Figure 4-25B). If the hidden lines show object to clarify relationships and positions in corners, the dashes touch the corners, as shown the drawing. To reduce confusion, special line in Figure 4-25C. symbols, or linetypes, are used to differentiate Dashes for hidden arcs start and end at the tan- between object lines and lines that have other gent points, as shown in Figure 4-26A. When special meanings. a hidden arc is tangent to a visible line, leave a space, as shown in Figure 4-26B. When a hid- Hidden Lines den line and a visible line project at the same It is necessary to describe every part of an place, show the visible line. See Figure 4-26C. object. Therefore, every detail must be repre- When a centerline and a hidden line proj- sented in each view, whether or not it can be ect at the same place, draw the hidden line, as seen. Both interior and exterior features are shown in Figure 4-27A. When a hidden line projected in the same way. Parts that cannot be crosses a visible line as in Figure 4-27B, do seen in the views are drawn with hidden lines not cross the visible line with a dash. When

ARCS END AT TANGENT POINT NO SPACE A

SPACE B

SPACE B SPACE NO SPACE SPACE

C C DASHES TOUCH SHOW FULL LINE

Figure 4-25 Figure 4-26 Treatment of hidden lines Treatment of hidden arcs

108 Chapter 4 Basic Drafting Techniques hidden lines cross, the nearest hidden line has the “right of way.” Draw the nearer hid- A den line through a space in the farther hidden line, as in Figure 4-27C. SHOW HIDDEN LINE — NOT C Centerlines Centerlines are special lines used to locate views and dimensions (see the alphabet of lines, Figure 4-18). Primary centerlines, marked P in Figure 4-28, locate the center on symmetrical views in which one part is a mir- B ror image of another. Primary centerlines are used as major locating lines to help in making FULL LINE IN FRONT the views. They are also used as base lines for SPACE dimensioning. Secondary centerlines, marked S in Figure 4-28, are used for drawing details of a part. Primary centerlines are the ﬁ rst lines to be drawn. The views are developed from them. Note that centerlines represent the axes of C cylinders in the margin view. The centers of circles and arcs are located ﬁ rst so that mea- LEAVE SPACE FOR NEAREST LINE surements can be made from them to locate the lines on the various views. As you may recall from the previous section, when a hidden line falls on a centerline, the hidden line is drawn. When a hidden line falls on a visible line, draw the visible line. Figure 4-27 Technique for presenting hidden and visible lines

Identify What drafting tools are used to draw vertical lines?

P CL

S S

S S P

Figure 4-28 S S Primary and secondary CL = CENTERLINE P = PRIMARY CENTERLINE centerlines S = SECONDARY CENTERLINE

Section 4.2 Creating a Drawing 109 Working with Drawing Ann Garvin Instruments How can you further improve the accuracy of your drawings? NEEDLE - POINT LEG PENCIL The correct use of drawing instruments LEG plays an important role in creating an accu- PERPENDICULAR TO SURFACE rate drawing. The following paragraphs explain how to use the basic drawing instruments.

Using the Dividers RADIUS OVER 2" To transfer a distance using the dividers, adjust the points to exactly the length to be Figure 4-30 transferred, such as the radius of a circle or the Adjusting the compass for large circles length of a line. Transfer the length by posi- tioning the dividers at a new location. You can also use the dividers to divide a line, arc, or circle into equal parts. For exam- the points of the dividers by an amount ple, to divide a line into three equal parts: about one third the distance. Then start at the beginning of the line again. 1. Adjust the points of the dividers until 6. If the last point overruns the end of the they seem to be about one third the line, decrease the distance between the length of the line. To adjust the divid- points by one third the extra distance. ers, hold them between your thumb and index fi nger. Set them to the desired For four, fi ve, or more spaces, follow the radius using your third and fourth fi n- same rules, but correct by one fourth, one gers, as shown in Figure 4-29A. fi fth, etc., of the overrun or underrun. You 2. Put one point on one end of the line and can divide an arc or circle in the same way. the other point on the line, as shown in Figure 4-29B. Using the Compass 3. Turn the dividers about the point that As you may recall from Chapter 3, the com- rests on the line, as in Figure 4-29C. pass is used to draw regular curves, such as 4. Then turn them in the alternate direc- circles and circular arcs. Leave the legs of the tion, as in Figure 4-29D. compass straight for radii under 2 (50 mm). 5. If the last point falls short of the end of For larger radii, make the legs perpendicu- the line, increase the distance between lar (at a 90° angle) to the paper, as shown in AB C D

Figure 4-29 The dividers are used to divide and transfer distances.

110 Chapter 4 Basic Drafting Techniques Ted Mishima Ted

LENGTHENING BAR

.38 + DRAWING SURFACE

NEEDLE POINT EXTENDS SLIGHTLY BEYOND THE LEAD POINT

Figure 4-31 Figure 4-32 Use the lengthening bar in compasses for circles Adjusting the point of the compass and arcs of large radii.

Figure 4-30. When you need a radius of more 1. Locate the center of the arc or circle by than 8" (200 mm), insert a lengthening bar as drawing two intersecting, or crossing, lines. shown in Figure 4-31 to increase the length 2. Lay off the radius by a short, light dash, of the pencil leg, or use a beam compass. as shown in Figure 4-33A. To get the compass ready for use, sharpen 3. Adjust the compass setting to the radius, the lead as shown in Figure 4-32, allowing as shown in Figure 4-33B. it to extend about .38" (10 mm). Then adjust 4. When the radius is set, raise your ﬁ n- the shouldered end of the needle point until gers to the handle, as shown in Figure it extends slightly beyond the lead point, 4-33C. as shown in Figure 4-32. You cannot use as 5. Turn the compass by twirling the handle much pressure on the lead in the compass as between your thumb and ﬁ nger. Start the you can on a pencil. Therefore, use lead one arc near the lower side and turn clockwise, or two degrees softer in the compass to get as shown in Figure 4-33D. As you draw the same line weight. Line weight refers to the curve, slant the compass a little in the the thickness and darkness of a line. direction of the line. Do not force the nee- To draw a circle or an arc with the compass, dle point into the paper. Use only enough follow these steps: pressure to hold the point in place.

AB C D

Figure 4-33 Technique for drawing circles and arcs

Section 4.2 Creating a Drawing 111 Using the Bow Instruments and Brown Ann Garvin, Arnold Bow Pencil The bow pencil is used to draw small circles. Whether you use instruments with center wheels or with side wheels is up to you. Sharpen and adjust the lead for the bow pencil, as shown in Figure 4-34A. The inside bevel holds an edge for small circles and arcs, as shown in Figure 4-34B. For larger radii, the outside bevel shown in Figure 4-34C is better. Some drafters prefer a conical center point or an off-center point, as shown in AB Figure 4-34D, E, and F. Use the bow pencil with one hand. Set Figure 4-35 the radius as shown in Figure 4-35A. Start Adjusting the radius for the bow pencil compass the circle near the lower part of the vertical centerline, as shown in Figure 4-35B. Turn clockwise. (Left-handers will need to reverse to open. Make small adjustments with the this procedure.) adjusting nut on both the side-wheel and the Drop-Spring Bow Compass center-wheel bows. Use the drop-spring bow compass to draw very small circles, as shown in Figure 4-36. Attach the marking point to a tube that slides List What are the steps involved in drawing a on a pin. Set the radius with the spring screw. small circle with a drop-spring bow compass? To use the drop-spring bow compass, ﬁ rst set the radius with the adjusting screw. Keep the pin still and turn the lead around it. Hold Using Irregular Curves the marking point up while putting the pin To use an irregular curve, ﬁ nd the points on the center. Then drop the marking point through which a curved line is to pass. Then and turn it. set the path of the curve by drawing a light line, freehand, through the points. Adjust it Adjusting Bow Instruments as needed to make the curve smooth. Next, You can make large adjustments quickly match the irregular curve against a part of with the side-wheel bows by pressing the fork and spinning the adjusting nut. Some center- wheel bows are also built for making large, Figure 4-36 rapid adjustments. To do this, hold one leg The drop-spring in each hand and either push to close or pull bow compass is used for drawing very small circles, Figure 4-34 especially when Bevels and points there are many to be drawn.

ABCDEF

112 Chapter 4 Basic Drafting Techniques 2

SECOND POSITION B

FIRST POSITION A

3 2 1

THIRD POSITION C

Figure 4-37 Steps in drawing a smooth curve

the curved line, as shown in Figure 4-37A, dimensions and notes on the assignment draw- and draw part of the line. Move the irregu- ings. For example in Problem 6, Figure 4-55A, lar curve to match the next part, and so on, you will notice such things as 2X, R44, and as shown in Figure 4-37B and C. Each new Ø54. The 2X is used to specify two times or two position should fi t enough of the part just places. The 2X in a dimension or note means drawn to make the line smooth. Note whether that the item being specifi ed appears twice on the radius of the curved line is increasing or that view or drawing. It eliminates the need to decreasing and place the irregular curve in the repeat the dimension for each detail that has same way. Do not try to draw too much of the identical size and shape. curve with one position. If the curved line is The R44 specifi es a radius of 44 millimeters symmetrical, or mirrored around an axis, and the Ø54 specifi es a diameter of 54 milli- mark the position of the axis or centerline on meters. Notice that there is no space between the irregular curve on one side. Then turn the the number and the symbol or abbreviation. irregular curve around to match and draw the Notice also that, except for the use of the let- other side. ter X, abbreviations and symbols are placed before the size dimension. Also, there is no space between the symbol or abbreviation Applying Drawing Skills and the size dimension. How do abbreviations and symbols help in Symbols and abbreviations are a form of drafting? drafter’s shorthand. They reduce the amount of time and space needed to provide critical infor- As you begin to work on the drawing prob- mation on the drawing. A list of the most com- lems at the end of the chapter, you will notice monly used abbreviations and symbols can be the use of various abbreviations and symbols in found in Appendix A.

Section 4.2 Creating a Drawing 113 Applying Basic Drawing Skills 7. Draw the vertical lines with T-square and triangle by setting the pencil on the Follow the procedure below to complete the marks on the bottom line and starting template drawing shown in Figure 4-38A. and stopping the lines on the proper hor- 1. Begin with an 11.00 17.00 drawing izontal lines, as shown in Figure 4-38E. sheet and prepare it with .40 borders on 8. Erase the lines not wanted (if necessary) the left, right, and bottom and a .60 bor- and darken the lines of the fi gure to fi n- der on the top. ish the drawing. Figure 4-38F shows the 2. Measure 3.80 from the left border line, fi nished template. Do not add dimen- and from this mark measure 8.50 toward sions unless instructed to do so. the right. 3. Lay the scale on the paper vertically near (or on) the left border line, make a mark 2.50 up from the bottom border line, and from this measure up 5.50 Identify What does the notation ‶2X″ more. The sheet will appear as in Figure indicate on a drawing? 4-38B. 4. Draw horizontal lines 1 and 2 with the T- square and triangle, as shown in Figure 4-38C. B 5. Lay the scale along the bottom line of the fi gure, with the measuring edge on the upper side, and make marks 1.70 apart. Then, with the scale on line 3 and its measuring edge to the left, measure from the bottom line two vertical distances, 2.50 and 1.50, as shown in Fig- C ure 4-38D. 1 6. Through the two marks, draw light horizontal lines. 34 2

Figure 4-38 D Template for drawing practice

1.70 1.70 1.70 1.70 E

1.50

3.00

5.50

3.80 8.50

2.50

114 Chapter 4 Basic Drafting Techniques When you are fi nished, press Enter to leave Working with CAD the LINE command. Commands Horizontal and Vertical Lines Which basic CAD commands are needed to AutoCAD allows you to create perfectly create a simple CAD drawing? vertical and horizontal lines with very little The commands in a CAD program are the effort. The Ortho mode forces every line “tools” the CAD operator uses to create draw- you draw to be either vertical or horizontal, ings. Instead of using a T-square and triangle as shown in Figure 4-39. To turn Ortho on, to create a 45° line, for example, the CAD pick the Ortho button at the bottom of the operator uses the LINE command to create the screen, or press the F8 function key on the line and specifi es a 45° angle. Commands vary keyboard. among CAD programs, and sometimes even among different versions of AutoCAD and Inclined Lines AutoCAD LT. Therefore, if you see a command The simplest way to create inclined lines in this text that does not appear in your soft- accurately is to use polar coordinates. Polar ware, use the software’s Help feature to fi nd coordinates include a specifi ed distance and out which command you should use instead. the angle at which the line should extend. For However, within AutoCAD and AutoCAD LT, example, suppose you have already entered most of the basic commands are the same. the LINE command and specifi ed the fi rst The sections that follow explain how to use point. Typing @2.50<45 when AutoCAD basic drawing commands in AutoCAD. As you prompts you for the next point creates a line read each section, pause and try out the tech- that extends 2.50 units at 45 degrees. nique in AutoCAD before continuing to read. Notice the required format for polar coordinates. The @ symbol tells AutoCAD that this Drawing Straight Lines coordinate will be relative to the last point Draw straight lines in AutoCAD by entering entered. The @ is followed by the length of the LINE command. The Command prompt the line. The < symbol represents “angle,” and (at the lower left corner of the screen) asks the last number is the specifi ed angle. for the fi rst point of the line. For now, use the mouse to pick a point anywhere in the draw- Polylines ing area. The prompt changes to ask for the All of the lines discussed so far, even those next point. Pick another point, and another. whose ends join, are actually individual line As you can see, you can continue picking segments. For many manufacturing uses, the points to create line segments indefi nitely. lines must be joined into a single line. Auto- CAD makes this possible by providing a polyline. A polyline is a line of any length, with any number of defi ning points, that is consid- ered by the software to be a single line object, as shown in Figure 4-40. Polylines can contain straight segments, curved segments, AB

Figure 4-39 Figure 4-40 The Ortho mode forces every line you draw to be Examples of perfectly vertical or horizontal. In this illustration, polylines the points shown in magenta represent the actual points picked by the CAD operator. The black lines show how AutoCAD draws the A corresponding lines with Ortho oﬀ (A) and with Ortho on (B). B

Section 4.2 Creating a Drawing 115 or both. To create a polyline, use the PLINE accurate than just pointing to a place on the command. Experiment with this useful com- screen to specify endpoints for lines, center mand until you feel comfortable using it. points for circles, and so on. One way to pro- The options that appear at the Command duce lines that meet exactly and are exactly line after you enter the fi rst point of a polyline the right length is to use coordinate entry. extend its usefulness. The most frequently This is a fairly slow method, and it has a used options for most applications are the major disadvantage: you must know or fi gure Arc and Close options. Arc allows you to add out the exact coordinates for every defi ning one or more curved segments to the polyline, point in the drawing. and Close joins the last point you entered to Fortunately, there are easier ways. Auto- the fi rst point of the polyline. This creates a CAD provides two tools called snap and grid perfectly closed shape, which is very impor- to help you select points accurately. Snap tant for use with computer-aided manufactur- sets the distance intervals at which the cur- ing (CAM) and computer numerical control sor moves when you move the mouse. For (CNC) systems. example, a snap of .25 allows you to enter points at exactly .25-unit intervals. While the Drawing Circles and Arcs snap is on and set to .25, you cannot acciden- Circles and arcs are easy to create in Auto- tally enter a point at .23 unit from the previ- CAD. In general, to create a circle, use the ous point. Snap is like a magnet that attracts CIRCLE command. To create an arc, use the points to the intervals you specify. ARC command. To turn the snap on, pick the Snap but- The easiest way to create a circle or arc is ton at the bottom of the screen or press the to specify a center point and a radius. The F9 function key. To set the snap interval, radius of a circle or arc is the distance from enter the SNAP command at the keyboard. its center point to any point on the rim of You can set the X and Y intervals to the the circle or arc (see Figure 4-41). However, same value or to different values. You can you can also use other methods, depending also rotate snap to any angle, and you can on how you need to incorporate the object specify whether you want a standard or into the drawing. You can specify a center isometric snap. point and diameter, for instance, or specify two tangent objects and a radius. Experi- ment with the options of the CIRCLE and ARC commands until you feel comfortable using them. Using Snap and Grid To create acceptable technical drawings, Coordinate Values you must use techniques that are more While the LINE command is active, move the mouse and watch the lower left part of the screen. The coordinate CENTER values of the cursor position appear POINT there. Double click the values to turn the coordinates on and off . Enter the LINE command and then turn the coordinates on and off more than once to notice that the coordinates

RADIUS can be shown either as coordinate pairs or as polar coordinates. For most Figure 4-41 work, polar coordinates are more useful. Use the coordinates with the snap The simplest way to create a circle in AutoCAD is and grid to make your work go faster. to specify a center point and a radius.

116 Chapter 4 Basic Drafting Techniques Figure 4-42 This method can be used even in the middle of many drawing commands, such as the 2.50 Setting snap and LINE command. This makes it a quick and grid values of .50 would help you easy way to correct mistakes without stopping 1.50 create this stencil to enter another command or losing your for the letter H train of thought. very quickly and 2.50 accurately.

1.50 2.50 1.50 Explain How do AutoCAD’s snap and grid features allow for greater accuracy?

Grid produces a nonprinting grid of dots Creating the Layout in Paper on the screen at intervals you specify. These Space dots provide a visual reference for the CAD operator. To turn grid on or off, pick the GRID Unless you have used a template that button at the bottom of the screen or press includes a pre-drawn or ISO border and title the F7 function key on the keyboard. To set block, you will need to create these items in the grid spacing, enter the GRID command at paper space before you can lay out the draw- the keyboard. You can set the X and Y settings ing properly in paper space for printing. to the same interval or to separate intervals 1. Pick the Layout1 tab at the bottom of (using the Aspect option). You can also set the drawing area to activate it. Notice them to correspond to the snap settings. that the stencil you created appears on a By setting up snap and grid intervals that will paper-like background inside a rectangle. be useful in your current drawing, you can cut In paper space, drawings actually appear down on drawing time. For example, to create in viewports. Viewports are invisible the stencil shown in Figure 4-42, you could set windows in the drawing area in which a the snap and grid to equal intervals of .50. view of the drawing can be placed. The rectangle is the default viewport. How- Erasing ever, it is not the right size for an A-size Erasing in AutoCAD takes two forms. You sheet. can either use the ERASE command, or you can 2. Enter the ERASE command, select the simply “undo” one or more of your actions. viewport, and press Enter to delete it. When you enter the ERASE command, The stencil disappears also, because AutoCAD asks you to select the objects to be model-space geometry requires a view- erased. You can pick them one by one with port to display in paper space. However, the mouse, or you can create a window by the stencil still exists in model space. You picking two diagonal corners of a rectangle. will create a new viewport to display the All objects inside the rectangle are selected for drawing properly, but ﬁ rst, you should erasure. When you have ﬁ nished selecting the add a border and title block. objects to be erased, press Enter to complete 3. Switch to the Border layer by selecting it the command. in the Layer Control drop-down box in AutoCAD has a formal UNDO command the Layers toolbar or on the Dashboard. that has several options. However, CAD oper- 4. Referring to the margin sizes in Table 4-1 ators usually just press the “u” key and then on page 93, use the LINE or PLINE com- Enter. This causes AutoCAD to undo the last mand to create a border for a horizontal action you took. If you press “u” again, Auto- A-size sheet. CAD continues to undo the previous actions 5. Create a title block in the lower right cor- sequentially. In this way, you can undo as ner of the drawing sheet, with its bottom many steps as necessary until the drawing and right sides aligned with the border. reaches the state at which it was last saved. 6. Switch to the Viewports layer.

Section 4.2 Creating a Drawing 117 7. Enter the VPORTS command to create a you have only to add the appropriate new viewport. Select the Single option text to the title block. and pick OK. 12. Enter the TEXT command and complete 8. Follow the prompts to create a rectangle the title block. Title the drawing STENCIL, the size of the border you created earlier. put your school name in the COMPANY This will be the new viewport. NAME AND ADDRESS block, specify a The stencil now reappears, but it is drawing size of A and a scale of 1:1. In the scaled arbitrarily to ﬁ t in the viewport. SHEET area, enter SHEET 1 OF 1. We want it to display on the drawing 13. Right-click on the Layout1 tab to display sheet at a scale of 1:1. the shortcut menu and select Rename. 9. Click once on the viewport (the magenta Give the layout a descriptive name such rectangle) to select it. Then right-click as A – STENCIL. and select Properties from the shortcut 14. Save the drawing. menu to display the Properties palette. 10. Pick the box next to Standard scale to If a drawing will not ﬁ t on the drawing activate the text box and display an sheet you have selected, you will need to use arrow, as shown in Figure 4-43. Pick a different drawing scale. The procedure is the the arrow and select 1:1 to set the draw- same as for creating a full-scale drawing. Just ing scale. change the scale in the Properties palette to 11. If the stencil overlaps the title block, pick the correct scale. the PAPER button on the status bar to Printing the Drawing return to model space within the layout. After you have set up the drawing in paper Enter the PAN command to move the space and entered the appropriate informa- stencil to a better location in the view- tion in the title block, you are ready to print port. Pick and hold with the mouse but- the drawing. ton while you move the geometry. The stencil is now properly displayed 1. Enter the LAYERS command and pick the at full scale. To complete the drawing, sun icon in the Viewports row to freeze

Figure 4-43 To change the scale of a drawing in paper space without changing the size of the border and title block, change the properties at the viewport in which the drawing appears. (A) Select Viewport to see the list of properties for the viewport. (B) Select the scale at which you want the drawing to appear.

118 Chapter 4 Basic Drafting Techniques the Viewports layer. This will prevent the 1. Create a new drawing using AutoCAD’s viewport rectangle from printing, but the ASME B template. stencil in the viewport will plot because 2. Switch to model space and set up the it is on the Objects layer. units. For this drawing, use decimal units 2. Enter the PLOT command. Check the with a length precision of two decimal printer settings, and make sure the plot places and an angle precision of zero dec- scale is set to 1:1. Then pick OK to print imal places. the drawing. 3. Set the model-space limits. This drawing will be printed at full size, so the limits should equal the sheet size. 4. Create the appropriate layers. This is a Explain How are viewports used to scale a fairly simple drawing that contains only drawing in AutoCAD? visible lines. You will not dimension this drawing, so you really only need an Objects layer. Create the layer and set it up for visible lines .30 mm thick. Leave the layer color at White. Applying the Concepts 5. Set the snap and grid. Review the tem- In what ways are board-drafting techniques plate in Figure 4-45 and notice that all different than CAD techniques? of the decimals are in multiples of .25. Therefore, .25 would make a good setting Practice is required to gain the skill for the snap and grid. needed to create accurate technical draw- 6. Save the drawing before you proceed. ings using CAD. The following procedure Give it a name that is easy to identify, steps you through the process of creating a such as Chapter 4 Practice, or name it drawing of the template shown in Figure according to your instructor’s directions. 4-44. This is the same drawing that is used 7. Refer again to Figure 4-45 to ﬁ gure out in the “Board Drafting Techniques” section where to start drawing. In this case, a of this chapter. If you are completing both convenient place to start is the lower procedures, notice the differences and simi- left corner of the template. Notice that larities between the board drafting and CAD it is 3.25 from the left side of the bor- techniques. der. This becomes the X coordinate for

1.75 1.75 1.75 1.75

1.50

3.00 Figure 4-44 Template for 5.50 drawing practice

3.75 8.75

2.25

Section 4.2 Creating a Drawing 119 prompt, for example, enter @8.75<0. 90° This draws an 8.75 horizontal line to the right from the ﬁ rst point. 10. For the second point, you will need to do ORIGIN 180° 0° a minor calculation. The length of the X AXIS line is the total length 5.50 less the 1.50 inset. Subtracting 1.50 from 5.50 equals 4.00, so the next line should be 4.00 drawn vertically bottom-to-top. There- 270° Y AXIS fore, you should enter @4.00<90. 11. Calculate and enter the remaining val- Figure 4-45 ues on your own. After you have entered the last value, press Enter to end the Polar coordinates. Notice that 0° lies to the right LINE command. Your ﬁ nished template of the origin along the X axis. The angle value increases counterclockwise through a complete should look like the one in Figure 4-45, circle. without the dimensions. 12. Pick the layout view tab to see how the drawing looks on the sheet layout. The drawing should appear to be the correct your starting point. It is 2.25 from the size for the drawing sheet, but it may bottom, so 2.25 becomes the Y coordi- seem a little off-center. You can change nate for the starting point. Therefore, the position of the drawing on the draw- the coordinates for the starting point are ing sheet by selecting the viewport and (3.75,2.25). entering the PROPERTIES command. There are two ways to proceed from here. You can determine the exact coordinates • At the top of the dialog box, select Viewport. of each of the remaining endpoints on the drawing, or you can use polar coordinates. The easier method, used in this exercise, is the polar coordinates method. Figure 4-45 shows the polar values for the angles you will need to specify. In general: • A line drawn horizontally to the right has an angle of 0°. • A line drawn horizontally to the left has an angle of 180°. • A line drawn vertically bottom-to-top has an angle of 90°. • A line drawn vertically top-to-bottom has an angle of 270°.

8. Enter the LINE command, and use the mouse to move the cursor until the coordinate display in the lower left corner shows the coordinates to be 3.75,2.25,0.00. (The third number is for three-dimensional drawings only, so you can ignore it for this drawing. Its value Figure 4-46 will always be 0.00.) Click to set the ﬁ rst The properties Center X and Center Y allow you point of the line at 3.75,2.25. to center the drawing on the drawing sheet for a 9. Work counterclockwise to draw the lines pleasing display. for the template. At the ﬁ rst Next point

120 Chapter 4 Basic Drafting Techniques • Scroll down the list until you see Center X • The origin of the line is the current hori- and Center Y, as shown in Figure 4-46. zontal or vertical center. These refer to the horizontal and vertical • Move the mouse and click to select a new centers of the drawing. center. • You can change the defaults either by entering a new numerical value or by using 13. Save the drawing ﬁ le. If your instruc- the mouse. tor requires a printed copy, print the • To use the mouse, pick the icon at the right drawing. See pages 118 and 119 under of the current value. A line appears in the the heading “Printing the Drawing” viewport. for more instructions on printing a drawing.

Section 4.2 Assessment Drafting Practice After You Read 7. Draw the item shown in Figure 4-47 below. Use the speciﬁ ed sheet size and scale. Do not dimension. Self-Check

1. List the basic drafting tools and equip- .75

ment used by the drafter. 1.75 7. 0 0 2. Name the line and line symbols recom- 5.00 1.50 5.50 mended by ASME. 3. Identify the basic commands used to

set up a drawing on a CAD system. 5.50 3.25 4. Describe the correct hand positions for 12.00 drawing lines with a technical pen and SHEET SIZE: B with a drafting pencil. SCALE: FULL SIZE 5. List the steps used to draw a circle with a compass. Figure 4-47 Academic Integration 8. Draw the frame shown in Figure 4-48. Mathematics Locate all centerlines before beginning to draw the frame. 6. Calculate Average Work Time Three

drafting students spent a total of four 4x R40 4x R60 hours working together to prepare a set 4x R30 of mechanical drawings. What is the average number of minutes each student 60 spends on the drawings? 1.0 0 Use Variables and Operations 134 268 Translating words into algebraic expres- sions requires knowledge of the mean- Figure 4-48 ing of the verbal descriptions. In algebra, a variable is a symbol used to represent a number. Arithmetic operations include Go to glencoe.com for this addition, subtraction, multiplication, book’s OLC for help with this and division. If x = the average num- drafting practice. ber of hours each worker spends on the drawings, the algebraic expression for the problem is 3x = (4 60).

Section 4.2 Creating a Drawing 121 4 Review and Assessment Chapter Summary Section 4.1 Section 4.2 • Preparing the drawing sheet includes • The use of a drafting pencil differs from choosing an appropriate size and type of the use of a technical pen. drawing sheet, fastening it to the drawing • The lines and line symbols used on draw- board, and laying out the borders and title ings come from the alphabet of lines. block. • Techniques for drawing circles, arcs, lines, • Preparing a drawing ﬁ le in CAD includes and inclined lines require the use of a creating a new drawing, selecting a draw- compass, circle template, T-square, pro- ing template for the appropriate standard tractor, drop-spring bow compass, dividers sheet size, and setting up units, limits, and or triangle. layers. • In a CAD system, the LINE, ORTHO, polar • Layers in AutoCAD have speciﬁ c proper- coordinate, and PLINE commands are ties such as line width, linetype, and color. used to produce straight lines, vertical or • Commands are the drafting tools used in horizontal lines, inclined lines, and to a CAD program. join lines into a single line, respectively. • Technical drawings created in CAD can The CIRCLE and ARC commands are be printed using ASME or ISO standard used to produce circles and arcs. Grid and layouts in paper space. snap commands produce lines that meet exactly.

Review Content Vocabulary and Academic Vocabulary 1. Use each of these content and academic vocabulary words in a sentence or drawing. Content Vocabulary • layer (p. 98) • polar coordinates (p. 115) • sheet layout (p. 91) • inking (p. 103) • polyline (p. 115) • reference zones (p. 92) • alphabet of lines (p. 105) • radius (p. 116) • revision history block (p. 92) • inclined lines (p. 106) • snap (p. 116) • application blocks (p. 92) • hidden lines (p. 108) • grid (p. 117) • drawing templates (p. 96) • centerlines (p. 109) • viewports (p. 117) • model space (p. 96) • line weight (p. 111) Academic Vocabulary • paper space (p. 96) • symmetrical (p. 113) • appropriate (p. 91) • limits (p. 97) • Ortho mode (p. 115) • differentiate (p. 108)

Review Key Concepts 2. Describe how to prepare a drawing sheet for a technical drawing. 3. Deﬁ ne the alphabet of lines. 4. Explain how the use of the drafting pencil and pen differs. 5. Describe how to use the compass and the dividers. 6. Explain how the snap and grid tools function in AutoCAD. 7. Explain how basic geometry is created to produce a technical drawing with CAD commands.

122 Chapter 4 Basic Drafting Techniques Technology Prep 8. Moving from Paper to Electronic True/False Questions The Bechtel Group is a large international For Directions Read the following engineering and construction company. statements and determine Among many of its achievements are the whether each statement is Hoover Dam and the “Chunnel” that runs true or false. underneath the English Channel. As projects 11. Parts of a drawing that cannot be are designed and reviewed, the company is seen in the views are drawn with migrating from paper to primarily electronic centerlines. drawings. For an international company with T marketing, legal, engineering, and construc- F tion groups, what advantages or disadvan- 12. A revision history block speciﬁ es revi- tages do you think accompany this change? sion dates and related information. Write a one-page paper explaining your ideas. T F

TEST-TAKING TIP 9. Ethics and Design Read statements slowly and carefully. If any You have been asked to design a desk that part of the statement is not accurate, then will be used in schools nationwide. Your the entire statement is false. For the state- manager asks you to consider the materi- ment to be true, every part must be true. als that the desks will be made from. Plastic laminates, wood, and particle board are some of your options. What issues might you consider in regard to construction costs, the environment, and safety? Give a ﬁ ve-minute Win presentation that details how you selected the Competitive materials for your design. Events 13. Job Interview Mathematics Organizations such as SkillsUSA offer 10. Calculate Dimensions a variety of architectural, career, and At her new job, Tina has been asked to cal- drafting competitions. Completing activ- culate the dimensions of the boxes for a new ities such as the one below will help you line of kitchenware. The volume of the boxes prepare for these events. can be no more than 1,800 cubic inches. To Activity Imagine an interviewer says, accommodate the products, the length must “Tell me about a mistake you made at be 15 inches and the height 10 inches. What work, and how you handled it after- should the width of the boxes be? wards.” Write four sentences describing how you could answer this question in Dimension and Volume a way that shows resourcefulness and a To calculate the volume of a three-dimen- positive attitude. sional ﬁ gure, use the formula V l w h. Use the information that you have to create Go to glencoe.com for this book’s an equation for the volume of the box. Use OLC for more information about w to represent the width. V 15 w 10. competitive events. Solve for w.

Review and Assessment 123 4 Problems

Drafting Problems The problems in this chapter can be performed using board drafting or CAD techniques. The problems are presented in order of difﬁ culty, from least to most difﬁ cult. Begin by drawing a border and title block if instructed to do so.

1. Draw each item shown in Figure 4-49

using the speciﬁ ed sheet size and scale. Do not dimension.

125 5.00 276 12 316 75 1.50 12

1.75 60 70

12 200 94 100 50 1.50 12412 200 12 96 200 8.00 416 METRIC A B METRIC C SHEET SIZE: A4 SHEET SIZE: A SHEET SIZE: A4 SCALE: 1:1 SCALE: FULL SIZE SCALE: 1:2

4.80 6

6.00 6.26 .20 8.00 1.60 1.40 .40 1.50 1.0 0 1.50 1.0 0 1.75 1.50 1.75 1.50 .25 2.26

4.80 6.00 132 SQ 1.0 0 1.60 6.26 1.75 8.00 SQ 172 2.20 .20 4.00 5.00 1.40 .25 • .40 1.501.0 0 .20 6 (TYP) (TYP) SPACE LINES 15 SQUARE (TYP) 3 mm APART D E F SHEET SIZE: A SHEET SIZE: A SHEET SIZE: A4 METRIC SCALE: FULL SIZE SCALE: 3/4 SIZE SCALE: 1:1

Figure 4-49

124 Chapter 9 Basic Drafting Techniques 2. Draw the grill plate shown in Figure 4. Practice using a civil engineer’s scale by

4-50. Make all ribs 12 mm wide. The dis- drawing the land parcel shown in Figure tance AB is 59 mm; BC is 88 mm; AD is 4-52. Measure the length of the closing 64 mm. The diamond shapes are 38 mm line to the nearest tenth of a foot and square. Sheet size: A4. Scale: 1:1. note it on your drawing. Sheet size: B. 1 40-0. F G AB = 600' E 90° C BC = 340' 105° 60° CD = 280' D F DE = 105' 90° AB = 55 mm 90° H EF = 100' E BC = 90 mm FG = 75' AD = 200 mm GH = 120' HA = ? AE = 65 mm CLOSING AF = 130 mm LINE K10 = 10 mm A B C D Dimensions 40mm ° METRIC 75° 90 Figure 4-50 B A

Figure 4-52

3. The drawing in Figure 4-51 provides 5. Draw the head gasket shown in Figure

practice in metric measurement. Draw 4-53. Scale: 1:1. horizontal line AB 180 mm long. Work clockwise around the layout. Remem- ber: Angular dimensions are the same in AB = 90 mm D the U.S. Customary and metric systems. C = R60 mm Measure the closing line and measure C F F C D = R40 mm E E E = Ø60 mm and label the angle at H. Sheet size: A4. F = Ø90 mm A B Scale: 1:1. G = Ø20

E H D ° 90° 90° 60 G – 7 HOLES ° 75 D G AB = 180 mm C BC = 60 mm Figure 4-53 90° CLOSING LINE CD = 48 mm DE = 42 mm 120° 75° EF = 74 mm FG = 50 mm B A GH = 90 mm METRIC Figure 4-51

Problems 125 4 Problems

6. Draw each item in Figure 4-54. Before you begin each drawing, determine a suitable sheet

size and scale. Include all centerlines. Do not dimension.

2X 4X Ø24 R64 Ø54 Ø.62 R.75 R.56

2.50 4.50 .75

R44 150 METRIC 6.00 B 8.00 A 2X R53.98/2.125 Ø38.10/1.50 4X Ø16 EQUALLY Ø44 SPACED

Ø136 Ø98 R82.55/3.25 METRIC C 127.00 MM ; MM/IN. 96 10X18 5.00 IN. D 120 4X .70 3 2 1.0 0 30º 4 1 Ø76 72 .60 30° 3 2 .50 1.88 4 1 15º 5 Ø1.884.00 4X 15° 5 Ø.62 Ø58 6 R.622X R.80 6 7 0 Ø36 10X 7 0 Ø12 88 9 9

4.38 NOTE:Note: NUMBERS numbers ARE are 6 10mmmm HIGH high E 4.40 SQ F METRIC

3X Ø.56 Ø2.25 15.8 120.6 4X .62 4.75 Ø19/.75 30° Ø4.50

1.12 57.2 2.25

3.88 R.62 R9.53/.38 G 152.4 R19/.75 6.00 H MM METRIC ; MM/IN. IN Figure 4-54

126 Chapter 4 Basic Drafting Techniques 7. Draw each item in Figure 4-55. Determine a suitable sheet size and scale. Include all center-

lines. Do not dimension.

2X Ø44.45/1.75 180 82 60

28 58

58 112 29 3X Ø14 139.70 5.50 MM 58 R57.15/2.25 ; MM/IN. ABIN. METRIC

R42 R1.12 R66 2X R1.12 Ø2.75 R2.00 R.50 R1.00 R12 88 R12 3.50 60° ° 60 24 4X Ø.75

96 48 190 3.38 C 7.50 METRIC D Figure 4-55

8. Draw the offset bracket shown in Figure 4-56. Locate all center points before beginning to

draw circles and arcs. Do not dimension.

10.62 R1.12

R.62

R2.88 1.68 (2.25)

1.75 (7.12) 2X O 1.00

Figure 4-56

Problems 127 4 Problems

9. Draw each item shown in Figure 4-57. Locate and mark points of tangency. Determine an

appropriate sheet size and scale. Include all centerlines. Do not dimension.

4.60

O .60 2.62 5 HOLES EQUALLY SPACED POINTR2.12 OF R 5.00 STRAIGHT TANGENCY POINTS OF 6.00 4.75 LINE TANGENCY R.50 R3.50 2.50 2.50 O 5.96 R1.25 R 3.50 R 1.30 R.61

O 4.78 .10 R2.50 .06 1.0 0 .3 .25 1.38 1.28 O 3.40 5.50 11.0011.00 A

1.00 O1.50 R 1.50 1.00

2x R .24 R.25 R 1.00 .75 R1.50 .50 .50 B .50.50 O1.0 0 R1.25 .50 R 1.00 2.001.50 4.70 30° 12 7X R6 R64 C O30 R52 19 15°

O22 O16 30° 30° O34 86 METRIC

NOTE: SMALL RADII R6 Ø110 D O.88 3 HOLES EQUALLY SPACED

Ø76 Ø48 O3.20

O4.40 6X R.80

O5.20 R1.00

METRIC E 4X R8 F

Figure 4-57

128 Chapter 4 Basic Drafting Techniques 10. Draw the multiple dial plate shown in 12. Draw the pawl shown in Figure 4-60.

Figure 4-58. Create the centerlines at Scale: 1:1. right angles. Distances FC, FD, FG, FE, 2X R.50 EA, and GB are 6.00 each. The diameter R3.00 R1.00 2X of the inner ring with center F is 4.50 . R.50 Diameters of all other inner rings are 5.50 1.0 0 4.00 . Scale: 3 1 -0 (1:4). .50

H 4X R.50 O 1.0 0 C 1.0 0 2.50 4.00 8.50

AE F GB Figure 4-60

Figure 4-58

11. Draw the double dial plate shown in 13. Draw the tilt scale shown in Figure 4-61.

Figure 4-59. Line AB = 7.00, and dis- Scale: 1:1. tances AC, CD, and DB are equal. Radii of inner arcs with centers at C and D R.30 2X R R.20 R 3.50 1.50 and 1.70 , respectively. Radii of R2.90 outer arcs with centers E and F are 3.70 R2.00 30 R3.80 and 3.90 respectively. Scale: Full size. 30 4 5 5 4 60 60 7 5 90 75 F Figure 4-61 ABCD

Figure 4-59

Problems 129 4 Problems

FGG F

14. Construct the irregular poly- ° ° gon shown in Figure 4-62. E 135° 105 105 135° E

Begin by drawing line AA 105° H H 105° centered near the bottom of D D the sheet. The length of each C C AA = 140 60° I 60° line is given in millimeters AB = 90 at the right of the polygon. 270° BC = 80 CD = 90 75° 75° Scale: 1:2. B B DE = 40 150° 150° EF = 50 FG = 100 GH = 60 Figure 4-62 A A

15. Draw the wire rope hook shown in 16. Draw the adjustable link shown in

Figure 4-63 using the dimensions selected Figure 4-64. Scale: 1:1. by your instructor. Determine the radii necessary for smooth tangencies.

R. 40

2x R. 50 C 1.80 DIA R. 80 .750 DIA 15º 1.30 30º

D R 3.40 A .88 DIA R .70 4.00 1.50 TO TITLE BLOCK

5.60 TO BORDER E METRIC

B Figure 4-64

Wire Rope Hook ABC D E 4.94 3.20 .88 1.06 .84 5.44 3.50 1.00 1.12 .90 6.25 4.10 1.12 1.25 1.12 6.88 4.54 1.25 1.38 1.30 7.62 4.88 1.38 1.50 1.38 8.60 5.75 1.50 1.70 1.56 9.50 6.38 1.16 1.88 1.70

Figure 4-63

130 Chapter 4 Basic Drafting Techniques R Ø.38 SLOTS 17. Draw a gasket for the bottom

R.30 of the guide block shown .38 .24 R.34 R.48 in Figure 4-65. It should be shaped so that when cut 1.0 0 2.24 out, it will touch only the 1.12 metal surface on the bottom. .24 .36 .43 Scale: 1:1.

3.96 6.50 ROUNDS AND FILLETS R.06 MATL – MALLEABLE IRON 2.36 .80 .2X Ø.64 R.64

.38 1.80 .16

1.0 0 .36

Figure 4-65

Design Problems Design problems have been prepared to challenge individual students or teams of students. In these problems, you are to apply skills learned mainly in this chapter, but also in other chapters throughout the text. The problems are designed to be completed using board drafting, CAD, or a combination of the two. Be creative and have fun!

Challenge Your Creativity Teamwork

1. Design a nightstand caddy to hold a 3. Design a ﬁ shing-tackle box. The design

watch, wallet, coins, jewelry, and other team should fi rst make a list of items items. First, sketch your design ideas and and quantities of items that the box is to then prepare instrument or CAD drawings accommodate. Next, work in groups of as assigned. Do not dimension. Material: two or three to design individual sections Optional. of the box. Then work as a full team to put the sections together into a fi nished Teamwork box design. A cardboard version could be made to help in visualizing the fi nal 2. Design a drawer divider to hold CDs and

DVDs. Inside drawer size: 6 deep 12 design. Material: 22-gauge galvanized wide 26 long. Material: Optional. Do sheet metal. Do not dimension. not dimension. Each team member should fi rst develop design sketches. The entire team should then select the best design (or combined design). Finally, each team member should prepare fi nished drawings of the fi nal design.

Problems 131