2Architectural RulerIs a specialized ruler. It is used in making or measuring from reduced scale drawings, such as blueprints and floor plans. It is marked with a range of calibrated scales (ratios).Architect's scale rulers used in Britain and other metric areas are marked with ratios without reference to a base unit. Therefore a drawing will indicate both its scale and the unit of measurement being used.
3The paired scales are 1:1/1:10 1:2/1:20 1:5/1:50 1:100/1:200 1:500/1:10001:1250/1:2500
4Architectural ScaleIn the United States, and prior to metrification in Britain, Canada and Australia, architect's scales are/were marked as a ratio of x inches-to-the-foot (typically written as x"=1'-0"). For example one inch measured from a drawing with a scale of "one-inch-to-the-foot" is equivalent to one foot in the real world (a scale of 1:12) whereas one inch measured from a drawing with a scale of "two-inches-to-the-foot" is equivalent to six inches in the real world (a scale of 1:6). It is not to be confused with a true unit less ratio (inches to inches)-- a 1:50 architectural scale would be a 1:60 unit less scale.Typical scales used in the United States are:Full scale, with inches divided into sixteenths of an inchThe following scales are generally grouped in pairs using the same dual-numbered index line:three-inches-to-the-foot (3"=1'-0") (ratio equivalent 1:4)/one-and-one-half-inch-to-the- foot (1-1/2"=1'-0") (1:8)one-inch-to-the-foot (1"=1'-0") (1:12)/one-half-inch-to-the-foot (1/2"=1'-0") (1:24)three-quarters-inch-to-the-foot (3/4"=1'-0") (1:16)/three-eighths-inch-to-the-foot (3/8"=1'-0") (1:32)one-quarter-inch-to-the-foot (1/4"=1'-0") (1:48)/one-eighth-inch-to-the-foot (1/8"=1'-0") (1:96)three-sixteenths-inch-to-the-foot (3/16"=1'-0") (1:64)/three-thirty-seconds-inch-to-the- foot (3/32"=1'0") (1:128)
5Engineers Scale RulerAn engineer's scale is a tool for measuring distances and transferring measurements at a fixed ratio of length. It is commonly made of plastic and is just over twelve inches (300 mm) long, so that the measuring ticks at the edges do not become unusable by wear. It is used in making engineering drawings, commonly called blueprints, in scale. For example, "one-tenth size" would appear on a drawing to indicate a part larger than the paper itself. It is not to be used to measure machined parts to see if they meet specifications.
6The engineer's scale came into existence when machining parts required a greater precision than the usual, binary fractionalization of the inch as in the architect's scale for houses and furniture. They were used, for example, in laying out printed circuit boards with the spacing of leads from integrated circuit chips as one-tenth of an inch. In the twenty-first century, those which are commonly purchased in the US are actually made in Germany.
7An engineer's scale, although identical at first glance to the architect's scale, it has a different set of measurements.
9How to Read a Scaled Ruler? Locate appropriate scale factor at end of scale rulerPlace line or object to be measured at zeroRead measurements from side of scale factor to end of line or objectScale factor on left = Read measurements from left to rightScale factor on right = Read measurements from right to leftBe careful to read measurements from lowest to greatest (ascending) orderBe careful not to read measurements from scale factor from other end of scale rulerTo measure foot increment, move scale ruler to lowest foot increment and recordTo measure inch increment, measure line or object from left of zero (scale factor on left) or right of zero (scale factor on right)Note: Measurements from zero to scale factor are 12 inches or 1 footDetermine measurements by determining 3”, 6” and 9” increments firstRecord measurement in foot and inches. Do not forget symbols for foot ( ‘ ) and inches ( “ )
15DrafterDrafters prepare technical drawings and plans, which are used to build everything from manufactured products such as toys, toasters, industrial machinery, and spacecraft to structures such as houses, office buildings, and oil and gas pipelines.
16Drafting Specialties Drafting work has many specialties: Aeronautical drafters prepare engineering drawings detailing plans and specifications used in the manufacture of aircraft, missiles, and related parts.Architectural drafters draw architectural and structural features of buildings and other structures. These workers may specialize in a type of structure, such as residential or commercial, or in a kind of material used, such as reinforced concrete, masonry, steel, or timber.Civil drafters prepare drawings and topographical and relief maps used in major construction or civil engineering projects, such as highways, bridges, pipelines, flood control projects, and water and sewage systems.Electrical drafters prepare wiring and layout diagrams used by workers who erect, install, and repair electrical equipment and wiring in communication centers, power plants, electrical distribution systems, and buildings.Electronics drafters draw wiring diagrams, circuit board assembly diagrams, schematics, and layout drawings used in the manufacture, installation, and repair of electronic devices and components.Mechanical drafters prepare drawings showing the detail and assembly of a wide variety of machinery and mechanical devices, indicating dimensions, fastening methods, and other requirements.Process piping or pipeline drafters prepare drawings used in the layout, construction, and operation of oil and gas fields, refineries, chemical plants, and process piping systems.
17Manual DraftingThe basic drafting procedure is to place a piece of paper (or other material) on a smooth surface with right-angle corners and straight sides—typically a drafting table. A sliding straightedge known as a T- square is then placed on one of the sides, allowing it to be slid across the side of the table, and over the surface of the paper.
18Manual DraftingParallel lines" can be drawn simply by moving the T-square and running a pencil or technical pen along the T-square's edge, but more typically the T-square is used as a tool to hold other devices such as set squares or triangles. In this case the drafter places one or more triangles of known angles on the T-square—which is itself at right angles to the edge of the table—and can then draw lines at any chosen angle to others on the page. Modern drafting tables (which have by now largely been replaced by CAD workstations) come equipped with a parallel rule that is supported on both sides of the table to slide over a large piece of paper. Because it is secured on both sides, lines drawn along the edge are guaranteed to be parallel.In addition, the drafter uses several tools to draw curves and circles. Primary among these are the compasses, used for drawing simple arcs and circles, and the: French curve, typically a piece of plastic with complex curves on it. A spline is a rubber coated articulated metal that can be manually bent to most curves.
21Line Conventions Line Conventions Introduction to Engineering DesignTM Unit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsProject Lead The Way, Inc.Copyright 2007
22Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsLines of varying style and thickness are used in specific ways to develop and communicate graphic messages about an object’s geometry. The next few slides show some basic line conventions and their use.Project Lead The Way, Inc.Copyright 2007
23Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsConstruction LineConstruction Line: Very lightly drawn lines used as guides to help draw all other lines and shapes properly.Ask students after slide first appears: What do you notice about this sketch? (Making sure you lead them into looking at the different line conventions or types that appear in the sketch). Imagine if all the lines here had the same thickness, weight and consistency. What do you think this sketch would look like then?Project Lead The Way, Inc.Copyright 2007
24Line Conventions Object Line Object Line Object Lines: Lines are thick Introduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsObject Lines: Lines are thickand dark; used to define theobject..Object LineObject LineProject Lead The Way, Inc.Copyright 2007
25Line Conventions Hidden Line Hidden Line Introduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsHidden Line: Lines used to show interior detail that is not visible from the outside of the part.Hidden LineHidden LineProject Lead The Way, Inc.Copyright 2007
26Line Conventions Center Line: Lines that define Introduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsCenter Line: Lines that definethe center of arcs, circles, orSymmetrical parts. They are half as thick as an object line.Center LineSTOP PRESENTATION: Students have the line conventions needed for the activities in Lesson 1.2.Center LineProject Lead The Way, Inc.Copyright 2007
27Line Conventions Section Line Section Line Introduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsSection Lines: Lines are used to define where there is material after a part of the object is cut away.Section LineSTOP PRESENTATION: Students have the line conventions needed for the activities in Lesson 1.2.Section LineProject Lead The Way, Inc.Copyright 2007
28Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsShort-Break Line: A freehand drawn line that shows where a part is broken to reveal detail behind the part or to shorten a long continuous part.Short-Break LineSTOP PRESENTATION: Students have the line conventions needed for the activities in Lesson 1.2.Project Lead The Way, Inc.Copyright 2007
29Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsDimension Lines: Lines that are used to show distance.Arrows are drawn on the ends to show where the dimension line starts and ends.The actual distance is usually located in the middle of this line to let you know the distance being communicated.Understanding Line types and when to use them will help your sketches look cleaner and more professional.Dimension LineDimension LineProject Lead The Way, Inc.Copyright 2007
30Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsExtension Lines: Lines used to show where a dimension starts and stops on an object.Used with dimension lines to properly dimension an object.The line is 1/16” away from the part as to not get confused with the object lines.Understanding Line types and when to use them will help your sketches look cleaner and more professional.Extension LineExtension LineProject Lead The Way, Inc.Copyright 2007
31Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsLong-Break LineLong-Break Lines: Used to shorten very long objects that do not change in detail.The line is usually represented as a jagged cut or break.Understanding Line types and when to use them will help your sketches look cleaner and more professional.Project Lead The Way, Inc.Copyright 2007
32Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsLeader LineLeader Lines: Leader lines are used to show dimensions of arcs, circles and to help show detail.Leader LineProject Lead The Way, Inc.Copyright 2007
33Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingLine ConventionsThough these standards relate to technical drawing, which is far more precise than freehand sketching, their conventions should be used as a guide when sketching.Project Lead The Way, Inc.Copyright 2007
34Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingPrecedence of LinesWhen sketching complex objects, different line types will often overlap each other. Therefore, line precedence must be exercised.Project Lead The Way, Inc.Copyright 2007
35Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingPrecedence of LinesThe following are rules that govern line precedence in sketches and technical drawings.Object lines take precedence over hidden and center lines.Hidden lines take precedence over center lines.Cutting plane lines take precedence over all others.This will make more since to the students when they do the multiview sketch activitiesProject Lead The Way, Inc.Copyright 2007
36Precedence of Lines Object lines take precedence over Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingPrecedence of LinesObject lines take precedence overthe hidden lines.An object line here takesprecedence over the center line.You may want to save this slide until you start multiview sketch activity.Project Lead The Way, Inc.Copyright 2007
37Line ConventionsIntroduction to Engineering DesignTMUnit 1 – Lesson 1.2 – Intro to Technical SketchingPrecedence of LinesAn object line here takesprecedence over the hidden line.Object lines take precedence over the center lines you would see from the hole.Object lines take precedence over the hidden lines you would see from the slot cut out in top view.An object line here takesprecedence over the center line.Project Lead The Way, Inc.Copyright 2007
38Technical SketchLike an artist may use sketches to develop ideas for a painting or sculpture, technical sketches are used during the development of ideas for initial or preliminary plans. The ability to make quick and accurate sketches is a valuable advantage that helps you convey design ideas to others. A sketch may be of an object, an idea of something you are thinking about, or a combination of both. Most of us think of a sketch as a freehand drawing, which is not always the case. You may sketch on graph paper to take advantage of the lined squares, or you may sketch on plain paper with or without the help of drawing instruments. Technical sketches are drawn without mechanical aid, like a t-square, compass, or straight edge, but, like other forms of architectural drafting, are drawn to scale and contain a variety of line weights and line styles (Figure 1). The pencil or pen is guided by the hand of the drafter alone and this is usually done on trace paper over a 1/4" grid paper. The grid paper becomes the guide helping to keep lines straight.
39LetteringLettering is used on drawings to give dimensions and other pertinent information needed to fully describe the item.The lettering must be neat and legible if it is to be easily read and understood.A drawing will be improved by good lettering.However, a good drawing will look sloppy and unprofessional if the lettering is poorly done.
40Lettering, Continued…The American National Standards Institute (ANSI) recommends that the Single-Stroke Gothic Alphabet be the accepted lettering standard
41Lettering, Continued…It can be drawn rapidly and is highly legible because each part of every letter is made by a single stroke.
42Lettering, Continued…This is because there are no serifs on the letters of this alphabet.A serif is like a tiny foot on a letter; alphabets that have serifs are more difficult to letter by hand. An alphabet without serifs is always called a san serif alphabet.
43Lettering, Continued…Today, because of computers, there are many different alphabet styles (also called fonts).When lettering a drawing, if the single stroke Gothic alphabet is not available, choose a san serif font and use only upper case letters.
44Good Lettering, Continued… Use guide linesGuide lines should be drawn so lightly they will not show up on a print made from the drawingVertical guide lines may be used to assure that the letters will be verticalInclined guide lines are drawn at 67 1/20 to the horizontal line when inclined lettering is to be used.INCLINED GUIDE LINES HELP KEEP INCLINED LETTERING UNIFORM
45Good Lettering, Continued… Only one form of lettering should appear on a drawing.AVOID COMbINING SEVERAL fORMS Of LETTERING.
46Lettering, Continued… Spacing: Proper spacing of the letters is important.The letters should be placed so spaces between the letters appear to be about the same.SPACED VISUALLYSPACED BY MEASURING