Presentation on theme: "CHAPTER 2 Drafting Equipment, Media, and Reproduction Methods."— Presentation transcript:
CHAPTER 2 Drafting Equipment, Media, and Reproduction Methods
Learning Objectives Describe and demonstrate the use of manual drafting equipment and supplies Explain the concept of drawing scale, and identify common inch and metric scales Read metric, civil engineer, architect, and mechanical scales
Learning Objectives Describe and use drafting media, sheet sizes, and sheet blocks and symbols Explain common drawing reproduction methods
Manual Drafting (Hand Drafting) Mostly replaced by computer-aided design and drafting (CADD) Manual drafting and CADD require understanding the basics of drafting Scale Sheet size Sheet format
Manual Drafting Equipment and Supplies Historical reference Still valuable for: Sketching Taking measurements Other related activities Still used by some companies for certain applications
Automatic Pencils Common for manual drafting, sketching, and office use Do not require sharpening Available in several different lead sizes Combination of 0.5, 0.7, and 0.9 mm pencils and leads good for sketching and daily use
Lead Grades Different grades of hardness for specific techniques 2H and H good for typical daily office use 2H to F for thick lines 4H to H for thin lines 6H or 4H for construction lines and guidelines
Compasses Especially useful for large circles and arcs More time consuming than a template Bow compass (shown)
Parallel Bar Draw horizontal lines Use triangles to draw vertical lines and angles
Triangles Straightedge Draw angles Connect points 30°–60° triangle Angles of 30°–60°–90° 45° triangle Angles of 45°–45°–90°
Templates Circles Ellipses Letters Specific requirements and drafting disciplines Examples: Architectural symbols Electronic schematic symbols
Irregular Curves Have no constant radii French and flexible curves Radius curve
Drafting Machines Generally take the place of triangles and parallel bars Maintains a horizontal and vertical relationship between scales Scales serve as straightedges Protractor allows scales to be set quickly at any angle
Scale Measurement instrument Specific scales for mechanical, architectural, civil, and metric drawings Used by manual drafters to help create scaled drawings Still useful for sketching, taking measurements, and related tasks Four basic shapes
Scale Concept A universal and critical design and drafting concept
Drawing Scale Drawings are scaled so the objects represented can be illustrated clearly on standard sizes of paper Depends on: Actual size of the objects drawn Amount of detail to show Media size Amount of dimensioning and notes required
Inch Mechanical Drawing Scales Full scale = FULL or 1:1 Half scale = HALF or 1:2 Quarter scale = QUARTER or 1:4 Twice scale = DOUBLE or 2:1 Four times scale = 4:1 Ten times scale = 10:1
Civil Engineer’s Scale Any multiple of ten 10 scale often used for mechanical drawings at full, decimal-inch scale (1:1) 20 scale common for mechanical drawings at half scale (1:2) 20 scale used for scales of 1" = 2', 1" = 20', and 1" = 200' 50 scale popular in civil drafting
Architect’s Scale 11 different scales Ten of the scales Inch represents a specific increment of feet Feet subdivided into multiples of 12 parts to represent inches and fractions of an inch Eleventh scale Full scale divided into 16 parts, each part equal to 1/16 of an inch
Mechanical Engineer’s Scale Common for mechanical drawings in fractional or decimal inches Full-scale divisions divided into 1/16, 10, and 50
Vellum Most common drafting mediamedia Inexpensive Good smoothness, erasability, and transparency Less durable and dimensionally stable Appropriate for regular graphite leads Well drawn graphite on vellum reproduces well
Polyester Film Mylar® Expensive Excellent durability, smoothness, erasability, dimensional stability, and transparency Best with ink or special polyester leads Well drawn ink on polyester film reproduces the best
Sheet Size and Format Standards for sheet size and format ASME Y14.1, Decimal Inch Drawing Sheet Size and Format ASME Y14.1M, Metric Drawing Sheet Size and Format Architectural, civil and structural drawings often use unique sheet format and may use unique sheet sizes
ASME Inch Sheet Size and Format [Insert Figure 2.31]
Selecting a Sheet Size Size of objects drawn Drawing scale Amount of additional content on the sheet Border Title block Drafting standards and company practice
ASME Inch Sheet Sizes Size Designation Size in Inches VerticalHorizontal A8 1/211 (horizontal format) 118 1/2 (vertical format) B1117 C 22 D 34 E 44 F2840 G, H, J, and K apply to specific roll sizes
ASME Metric Sheet Sizes Size Designation Size in Millimeters VerticalHorizontal A08411189 A1594841 A2420594 A3297420 A4210297 A1.0, A2.1, A2.0, A3.2, A3.1, and A3.0 apply to specific elongated sizes
Line Format Specified in ASME Y14.2M, Line Conventions and Lettering Thick lines of 0.6 mm (.02 in.) Borders Outline of principle blocks Main divisions of blocks Thin lines of 0.3 mm (.01 in.) Dividing parts lists and Revision History blocks Minor subdivisions of the title block and supplementary blocks
ASME Lettering Style Vertical uppercase Gothic Arial, Roman, or similar font when using CADD
ASME Letter Heights Sheet Elements Minimum Letter Heights INCH Drawing Sizes INCH Letter Heights METRIC (mm) Drawing Sizes METRIC Drawing title, sheet size, CAGE Code, drawing number, revision letter in the title block.24D, E, F, H, J, K6A0, A1 Drawing title, sheet size, CAGE Code, drawing number, revision letter in the title block.12A, B, C, G3A2, A3, A4 Zone letters and numbers in borders.24All sizes6 Drawing block headings.10All sizes2.5All sizes All other characters.12All sizes3
Border Format margin of a sheet Borderlines form a rectangle to establish the border ASME minimum distance from the edges of the sheet to borderlines:.5 in. for all inch drawing sheet sizes 20 mm for A0- and A1-size sheets 10 mm for A2-, A3-, and A4-size sheets
Zoning Allows the drawing to read like a road map Recommend by ASME standards for all sheets Optional for A, B, and A4 size sheets
Title Block Provides a variety of information about a drawing Size and location specified by ASME standards Other sheet blocks often group with the title block
ASME Title Block 1.Company or design activity 2.Title 3.Sheet size 4.CAGE CodeCAGE Code 5.Drawing number 6.Revision of the part or drawing 7.Principal drawing scale 8.Actual or estimated weight 9.Sheet relative to a group of sheets or set of sheets 10.Approvals 1 11.Approval 2 12.Approval 3
Angle of Projection Block Third angle projection First angle projection
Glossary Angle of projection block Specifies how to interpret a drawing according to the method of view projection. Application block Includes information such as next assembly and where used for drawings of a detail part or assembly of a component of a larger assembly. Automatic pencil A pencil with a lead chamber that advances the lead from the chamber to the writing tip by the push of a button or tab when a new piece of lead is needed.
Glossary CAGE Code A five number code assigned by the United States Defense Logistic Service Center (DLSC) to all Department of Defense contractors. CAGE stands for Commercial And Government Entity. Compass An instrument used to draw circles and arcs. Dimensioning and tolerancing block Specifies the general dimensioning and tolerancing specifications found on the drawing.
Glossary Dividers Used to transfer dimensions or to divide a distance into a number of equal parts. Dividers are also used in navigation to measure distance in nautical miles. Drafting machine A machine that mounts to the table or board and has scales attached to an adjustable head that rotates for drawing angles. Ellipse A circle seen at an angle.
Glossary Manual drafting (hand drafting) Traditional drafting practice using pencil or ink on a medium such as paper or polyester film, with the support of drafting instruments and equipment. Margin drawing number block Identifies the drawing number and sheet number, and optional revision, when reading the margin information on the drawing. Media The material upon which you create drawings, such as paper or polyester film.
Glossary Microfilm A film on which drawings or other printed materials are photographed at greatly reduced size for ease of storage and sending from one place to another. When needed, equipment is available for enlargement of the microfilm to a printed copy. Proportional dividers Used to reduce or enlarge an object without the need of mathematical calculations or scale manipulations. Revision History block Also called the revision block, is used to record changes to the drawing.
Glossary Revision status of sheets block Appears on the first sheet of multiple sheet drawings and records the revision status of each drawing. Scale An instrument with a system of ordered marks at fixed intervals used as a reference standard in measurement. A scale establishes a proportion used in determining the dimensional relationship of an actual object to the representation of the same object on a drawing. Templates Plastic sheets with accurate shapes cut out and are used as a stencil for drawing the shapes.
Glossary Vellum Drafting paper with translucent properties that is specially designed to accept pencil or ink. Xerography A dry photographic or photocopying process in which a negative image formed by a resinous powder on an electrically charged plate is electrically transferred to and fixed as positive on a paper or other copying surface. Zoning A system of numbers along the top and bottom margins and letters along the left and right margins.