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 techni- cal 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 usu- ally 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 appropri- ate 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 stan- dard 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 8.50Љ vertically are used to locate specifi c information on and 11.00Љ horizontally (8.50 ϫ 11.00). When the drawing. The title block provides basic placed in the vertical position, it is 11.00Љ ver- information about the drawing— the “who, tically and 8.50Љ horizontally (11.00 ϫ 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 11.00Љ .38 .25 A (Vertical) 11.00 8.50Љ .25 .38 B (Horizontal) 11.00 17.00Љ .38 .62 C (Horizontal) 17.00 22.00Љ .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.