BC WELDER TRAINING PROGRAM

Transcription

1 BC WELDER TRAINING PROGRAM FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2 Related Knowledge 2 (RK2) (Line I): Drawings, Layout and Fabrication I Theory Competencies

2 Acknowledgements & Copyright Permission The Industry Training Authority of British Columbia would like to acknowledge the Welding Articulation Committee and Open School BC, as well as the following individuals and organizations for their contributions in updating the Welder Training modules: Version 1 Contributors (2010) Welding Articulation Committee (WAC) Members and Consultants The Working Group Jim Carson (Welding Articulation Committee Chair), University of the Fraser Valley (writer and senior reviewer) Peter Haigh (Welding Curriculum Review Committee Chair), Northwest Community College (writer and senior reviewer) Sheldon Frank, University of the Fraser Valley (writer and reviewer) Greg Burkett, Okanagan College (writer and reviewer) Randy Zimmerman (writer and reviewer) John H.P. Little (reviewer) Resource Training Organization (RTO) BC Council on Admissions and Transfer (BCCAT) The Queen s Printer In 2010, the Queen s Printer, through its Open School BC unit, provided project management and design expertise in updating the Welder Training Level C print materials. Open School BC Solvig Norman, Senior Project Manager Eleanor Liddy, Director/Advisor Dennis Evans, Production Technician (print layout, graphics & photographs) Christine Ramkeesoon, Graphics Media Coordinator Keith Learmonth, Editor Margaret Kernaghan, Graphic Artist Publishing Services Sherry Brown, Director of Publishing Services Intellectual Property Program Ilona Ugro, Copyright Officer, Ministry of Citizens Services, Province of British Columbia Copyright Permission The following suppliers have kindly provided copyright permission for selected product images: Acklands-Grainger Inc. The Crosby Group J. Walter Company Ltd. Lincoln Electric Company NDT Systems, Inc. Praxair, Inc. Thermadyne Canada (Victor Equipment) The Miller Electric Mfg. Co. ESAB Welding & Cutting Products Photo of welder walks the high steel at a construction site, Kenneth V. Pilon, copyright Used under license from Shutterstock.com

3 A special thank you to Lou Bonin and Jim Stratford at Camosun College (Welding department) for assisting us with additional photographs. An additional thank you to Richard Smith from England, for allowing us to use photographs of hydrogen bubbles. Version 2 Contributors (2017) The Welding Level C Modules were updated in 2017 to reflect the 2016 (Harmonized) Program Outline with Levels 1 and 2 referenced throughout the covers, titles, headers, tabs and tab pages. Welding Articulation Committee Mark Flynn (Welding Articulation Committee Chair), British Columbia Institute for Technology Al Sumal, Kwantlen Polytechnic University Jim Carson, University of the Fraser Valley Colin Makeiv, Selkirk College Open School BC Jennifer Riddel, Manager of Instructional Services Solvig Norman, Project Manager Sharon Barker, Production Technician

4 Foreword The Industry Training Authority (ITA) is pleased to release this minor update of learning resources to support the delivery of the 2016 BC Welder Program Foundation and Apprenticeship Levels 1 and 2. It was made possible by the dedicated efforts of the Welding Articulation Committee of BC (WAC). The WAC is a working group of welding instructors from institutions across the province and is one of the key stakeholder groups that support and strengthen industry training in BC. It was the driving force behind the update of the welding learning modules supplying the specialized expertise required to incorporate technological, procedural and industry-driven changes. The WAC plays an important role in the province s postsecondary public institutions as discipline specialists that share information and engage in discussions of curriculum matters, particularly those affecting student mobility. We are grateful to WAC for their contributions to the ongoing development of BC Welder Training Program Learning Resources (materials whose ownership and copyright are maintained by the Province of British Columbia through ITA). Disclaimer Industry Training Authority March 2017 The materials in these modules are for use by students and instructional staff and have been compiled from sources believed to be reliable and to represent best current opinions on these subjects. These manuals are intended to serve as a starting point for good practices and may not specify all minimum legal standards. No warranty, guarantee or representation is made by the British Columbia Welding Articulation Committee, the British Columbia Industry Training Authority or the Queen s Printer of British Columbia as to the accuracy or sufficiency of the information contained in these publications. These manuals are intended to provide basic guidelines for welding trade practices. Do not assume, therefore, that all necessary warnings and safety precautionary measures are contained in this module and that other or additional measures may not be required.

5 (RK2) (Line I): Drawings, Layout and Fabrication I Theory Competencies Table of Contents Theory Competency RK2-1 (Line I-I3): Sketch Basic Objects Using Orthographic Projection 7 RK2-1 Learning Task 1: Orthographic drawings RK2-1 Learning Task 2: Basic lines used in drawings RK2-1 Learning Task 3: Sketch orthographic projections RK2-1 Learning Task 4: Sketch auxiliary and sectional views Theory Competency RK2-2 (Line I-I3): Sketch Isometric Drawings of Basic Objects 49 RK2-2 Learning Task 1: Pictorial drawings RK2-2 Learning Task 2: Sketch isometric drawings of basic objects RK2-2 Learning Task 3: Sketch isometric drawings of basic objects with circular features.. 75 Theory Competency RK2-3 (Line I-I3): Sketch Dimensioned Drawings 81 RK2-3 Learning Task 1: Systems of measurements used on drawings RK2-3 Learning Task 2: Methods of dimensioning Theory Competency RK2-4 (Line I-I1): Welding Symbols and Bolted Connections 103 RK2-4 Learning Task 1: Standard welding symbols RK2-4 Learning Task 2: Dimensioning fillet and groove welds RK2-4 Learning Task 3: Other basic weld symbols and their dimensions RK2-4 Learning Task 4: Dimensioning bolted connections Theory Competency RK2-5 (Line I-I2): Structural Drawings 161 RK2-5 Learning Task 1: Structural steel shapes RK2-5 Learning Task 2: Types of structural drawings RK2-5 Learning Task 3: Bills of materials and other information found on structural drawings Answer Key 215 BC WELDER TRAINING PROGRAM 5

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7 Theory Competency RK2-1 (Line I-I3): Sketch basic objects using orthographic projection RK2-1 (F, L1 & L2) The following table shows you where information about Levels 1 and 2 content are covered from the new Harmonized Program Outline (2016). RK2-1 LT1 Pages Level 1 Level 2 RK2-1 LT2 Pages Level 1 Level 2 RK2-1 LT3 Pages Level 2 RK2-1 LT4 Pages Level 2

8 theory Competency RK2-1 (Line I-I3) Outcomes The key to successfully interpreting blueprints is in understanding multi-view or orthographic projection. Most of the shop drawings and structural drawings you will work with as a Welder will be drawn using one or more of the six views of orthographic projection. You will need to become thoroughly familiar with the principles of this type of drawing and to develop skill in drawing the views required to depict basic objects. When you have completed the Learning Tasks in this Theory Competency, you should be able to: use the alphabet of lines describe the principles of orthographic projection describe the principles of scale drawings make three-view sketches of simple objects to the required scale describe the principle of sectioning describe auxiliary views Evaluation When you have completed all the Theory Competencies in module RK2, you will take a written test. You must score at least 70% on this test. The test will include questions that are based on the following material from Theory Competency RK2-1: orthographic drawings basic lines used in drawings principles of scale drawings principle of sectioning principles of auxiliary views Resources All the resources you will require are contained in this competency. BC WELDER TRAINING PROGRAM 9

9 10 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

10 theory Competency RK2-1 (Line I-I3) RK2-1 Learning Task 1: Orthographic drawings The main purpose of a drawing is to give all the information needed to manufacture a product or to assemble a structure. The most common way to show this information is to draw a series of views that illustrates each side of the part or structure. Understanding orthographic drawings This type of drawing is called a multi-view or orthographic drawing. To interpret or read these drawings you must first understand how the views in a multi-view drawing are developed and how each view relates to the other views. The best way to understand the principle of orthographic views is to begin by imagining that the object you wish to draw is inside a glass box (Figure 1). Figure 1 Object in imaginary glass box If you were to now look at the object through each side of the box, and draw with an imaginary pencil onto the glass the view of the object you see through the glass, you would end up with a sketch similar to that shown in Figure 2. BC WELDER TRAINING PROGRAM 11

11 theory Competency RK2-1 (Line I-I3) Figure 2 Sketch of each side of object Note that the view through each side of the glass box shows only the straight-on view of one side of the object, and that all lines are straight and parallel because the original object has sides that are straight and parallel. In other words, each view represents what you see when you look directly at each side of the object. If you now unfold your imaginary glass box (Figure 3), each view is in the correct position for a true orthographic drawing. Note that each view is given a name that reflects its position in relation to the other views. The front view is the closest panel to the viewer. Top-side view Rear-side view Front-side view Left-side view Right-side view Bottom-side view Figure 3 Views of sides unfolded 12 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

12 theory Competency RK2-1 (Line I-I3) When the imaginary glass box is flattened and then removed, you can see that each view is in line with the view next to it. You are now left with an orthographic drawing of the original object (Figure 4). These six views are called the six principal orthographic views. You will seldom need to show views of all six sides of an object, as usually it is sufficient to show two or three views. But you should remember the names of these six views and understand how they are obtained, in case you ever need to show an object that cannot be truly represented in two or three views. Top-side view Rear-side view Left-side view Front-side view Right-side view Bottom-side view Figure 4 Six views in proper alignment Placement of orthographic views There are two important things to remember about the placement of orthographic views: 1. The views must always be in the correct relationship to each other. The right-side view must always be to the right of the front view, the top must always be directly above the front view, the rear view must always be to the left of the left-side view, and so on. 2. The views must always be in line with each other, both vertically and horizontally. The top view must always be directly above and in line with the front view, and the bottom view must always be directly below and in line with the front view. The rear, left-side, front and right-side views must always be directly in line with each other and in their correct positions. Number of views required Unless an object is very complex, many times only the front, top and rightside views are shown. If the object has uniform thickness, only one or two views are shown. Figures 5, 6 and 7 each show you an object pictorially (in three dimensions) and the views necessary to fully describe the object using orthographic projection. BC WELDER TRAINING PROGRAM 13

13 theory Competency RK2-1 (Line I-I3) Figure 5, for example, shows an object that required only one view to fully describe its shape and size. Gasket Pictorial sketch Gasket One-view orthographic projection Figure 5 Pictorial and one-view orthographic Figure 6 shows an object that can be described fully in two views. Pictorial sketch Two-view orthographic sketch Figure 6 Pictorial and two-view orthographic Figure 7 shows an object that requires three full views to fully represent its shape. Drawings will never show more views than necessary to communicate the information required to fabricate the part. 14 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

14 theory Competency RK2-1 (Line I-I3) Pictorial sketch Three-view orthographic sketch Figure 7 Pictorial and three-view orthographic Now complete Self-Test 1 and check your answers. BC WELDER TRAINING PROGRAM 15

15 theory Competency RK2-1 (Line I-I3) Answers Self-Test 1 Choose the correct response for each question and put it in the Answers column. Cover your answers when reviewing the test for study purposes. 1. Given the views of each object below, indicate which view or views are out of place, if any. a. b. Top-side Top-side Front-side Right-side Front-side Right-side c. d. Top-side Top-side Front-side Right-side Front-side Right-side Figure 8 16 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

16 theory Competency RK2-1 (Line I-I3) 2. Study the objects in the sketches below and determine how many orthographic views are necessary to completely describe each object. Answers a. b. Corner bracket Bench hook c. d. Coffee table Pulley blank e. Special corner bracket Figure 9 Now go to the Answer Key and check your answers. BC WELDER TRAINING PROGRAM 17

17 theory Competency RK2-1 (Line I-I3) 18 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

18 theory Competency RK2-1 (Line I-I3) RK2-1 Learning Task 2: Basic lines used in drawings Every drawing is made with a series of lines. These lines describe the basic shape and form of the part. They also indicate any special details or features of the part. These lines are sometimes called the alphabet of lines. To properly read and interpret drawings, you must know the meaning of each line and understand how each is used to construct a drawing. Object lines Object lines are the most common lines used in drawings. These thick, solid lines show the visible edges, corners and surfaces of a part (Figure 10). Object lines stand out on the drawing and clearly define the outline and features of the object. Object lines (thick and solid) Hidden lines Figure 10 Object lines Hidden lines are used to show edges and surfaces that are not visible in a view. These lines are drawn as thin, evenly spaced dashes (Figure 11). Many times a surface or edge that is shown as an object line in one view will be shown as a hidden line in another view. Hidden lines (thin and dashed) Top Side view Centre lines Figure 11 Hidden lines Centre lines (Figure 12) are used in drawings for several different applications. The meaning of a centre line is normally determined by how it is used. Centre lines are thin, alternating long and short dashes that are generally used to show hole centres and centre positions of rounded features, such as arcs and radii. Arcs are sections of a circle, and radii are rounded corners or edges of a part. Centre lines can also show the symmetry of an object. BC WELDER TRAINING PROGRAM 19

19 theory Competency RK2-1 (Line I-I3) Centre line (thin with long and short dashes) Figure 12 Centre lines Dimension and extension lines Dimension and extension lines are thin, solid lines that show the direction, length and limits of the dimensions of a part (Figure 13). Dimension lines are drawn with an arrowhead at both ends. Extension lines are drawn close to the edges or surface they limit. They are normally perpendicular, or at right angles, to the dimension line. The length of extension lines is generally suited to the number of dimensions they limit. Dimension and extension lines (thin and solid) Types of dimensions Figure 13 Dimension and extension lines There are three types of dimensions (Figure 14): size dimensions location dimensions notation dimensions Size dimensions provide the overall size of an object and the size of individual details such as holes, slots and gussets. Size dimensions include length, width, height, diameter and angles. Location dimensions are necessary to place holes, gussets and other details on the object. Notation dimensions provide all other information needed to fabricate the component. These include hole size, specifications and welding information. 20 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

20 theory Competency RK2-1 (Line I-I3) All holes 11 16" unless noted Location Size Methods of dimensioning Figure 14 Types of dimensions Four methods are used to show size and location dimensions on fabrication drawings. They are: conventional dimensioning baseline dimensioning running dimensioning notation dimensioning The choice of method is determined by type of fabrication, size of the component or assembly, complexity of the component or assembly and accuracy or tolerance requirements. Conventional dimensioning Conventional dimensioning is the most widely used method (Figure 15). The overall size of the component or assembly is indicated by vertical and horizontal dimension lines. Each size dimension becomes a reference for the next. Conventional dimensions are used for welded fabrication of tanks, hoppers, bases and frames when tolerance is not rigid Figure 15 Conventional dimensioning BC WELDER TRAINING PROGRAM 21

21 theory Competency RK2-1 (Line I-I3) Baseline dimensioning Baseline dimensions are primarily used for machinery fabrication (Figure 16). One surface or edge of a component becomes a vertical reference and one becomes a horizontal reference. All size and location dimensions originate at these lines. Every value has its own dimension line. The advantage of this system is its extreme accuracy. A disadvantage is that the drawing can become complex and crowded Figure 16 Baseline dimensioning Running dimensioning Running dimensions are similar to baseline dimensions, but they have much different applications (Figure 17). All size and location dimensions originate at a single edge, but they share a single dimension line. Extension lines indicate details to be dimensioned, such as holes, stiffeners and gussets. Running dimensions are primarily used in structural fabrication of columns, beams and trusses Figure 17 Running dimensioning Notation dimensioning Linear location dimensions are often repetitious (Figure 18). A girder could require a stiffener at a given increment, or a conveyor frame could require many holes for bearing mounts at specific centres. Rather than cluttering up the drawing with lines and numbers, the draftsperson may use a single note, such as drill 7 20 mm holes at 40 mm centres. 22 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

22 theory Competency RK2-1 (Line I-I3) mm O/C Dimensioning angles Figure 18 Notation dimensioning Angular lines and surfaces are found in all areas of fabrication. There are three different methods for dimensioning angles (Figure 19) º A B C Figure 19 Dimensioning angles The least complicated method of dimensioning an angle is to simply provide a vertical and horizontal dimension for the angular component (Figure 19A). This method is handy for laying out large triangular plates or hoppers, but it has limited application and accuracy. A second method of dimensioning an angular surface or edge is to identify the number of degrees or fraction of a degree from a suitable horizontal or vertical reference (Figure 19B). This method is very accurate for machinery layout, pipe and plate development and welding preparation. The third method of angular layout requires a pitch or bevel ratio (Figure 19C). This method involves a right angle symbol and an accompanying ratio that indicates the desired slope. This method is universally used in structural steel fabrication for laying out slopes, skews and mitres. If the drawing uses metric measurement, the fixed value in the ratio is 250. If the drawing uses imperial measurement, the fixed value in the ratio is always 12. Dimensioning circles and arcs Full circles are common in fabrication drawings. They depict holes, pipes, bars and disks in many sizes and applications. Circles must be dimensioned by diameter. All circular views require a centre line (Figure 20). BC WELDER TRAINING PROGRAM 23

23 theory Competency RK2-1 (Line I-I3) Ø 1.75 Ø Figure 20 Dimensioning circles Partial circles (arcs) depict slotted holes and rounded corners. They must be dimensioned using their radius. Partial circles are always located by a centre line (Figure 21). r r 25 r Figure 21 Dimensioning partial circles Other kinds of lines Leader lines Leader lines show information such as dimensional notes, material specifications and process notes (Figure 22). These lines are normally drawn as thin, solid lines with an arrowhead at one end. They are bent or angled at the other end. When leader lines reference a surface, a dot is used instead of an arrowhead. 24 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

24 theory Competency RK2-1 (Line I-I3) Leader line (thin and solid) Flat bar 3 mm thick r 20 Ø 8 mm 2 holes Copper plate this surface Figure 22 Leader lines Phantom lines Phantom lines (like centre lines) are used for several purposes in drawings. Phantom lines are used to show alternate positions for moving parts and the positions of related or adjacent parts, and to eliminate repeated details (Figure 23). Phantom lines are drawn as thin lines consisting of a series of long dashes separated by two short dashes. Existing column New girder Figure 23 Phantom lines Cutting plane lines Cutting plane lines show the location and path of imaginary cuts made through parts to show internal details (Figure 24). In most cases, sectional views (or views that show complicated internal details of a part) are indicated by using a cutting plane line. These lines are thick, alternating long lines separated by two short dashes. The arrowheads at each end show the viewing direction of the related sectional view. The two main types of cutting plane lines are the straight and the offset. BC WELDER TRAINING PROGRAM 25

25 theory Competency RK2-1 (Line I-I3) Cutting plane line (thick with one long then two short dashes) A A B B Section A A Section B B Figure 24 Cutting plane lines Section lines Section lines indicate the surfaces in a sectional view as they would appear if the part were actually cut with the cutting plane line (Figure 25). These lines are solid lines that are normally drawn at 45 angles. Section lines (thin and solid) Section B B Figure 25 Section lines Break lines Break lines are drawn to show that a part has been shortened to reduce its size on the drawing. The two variations of break lines common to blueprints are the long break line and the short break line (Figure 26). Long break lines are thin, solid lines that have zigzags to indicate a break. Short break lines are thick, wavy, solid lines that are drawn freehand. When either of these break lines is used to shorten an object, you can assume that the section removed from the part to make it smaller is identical to the portions of the part shown on either side of the break. 26 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

26 theory Competency RK2-1 (Line I-I3) (thin and long with a zigzag) (thick and short, wavy freehand) Figure 26 Break lines Figure 27 shows the following kinds of lines applied in a drawing: 1. object line 2. hidden line 3. centre line 4. dimension line 5. extension line 6. projection line 7. cutting plane line 8. gauge line 9. section lines ½" 8 2' 2¾" Section A-A A 2 6 Auxiliary view 2' 1" 3" A 7 4' 8" 4 Front view 5 Figure 27 Various kinds of lines Now complete Self-Test 2 and check your answers. BC WELDER TRAINING PROGRAM 27

27 theory Competency RK2-1 (Line I-I3) Answers Self-Test 2 Choose the correct response for each question and put it in the Answers column. Cover your answers when reviewing the test for study purposes. 1. Identify the types of lines shown in Figure 28. a. object line b. hidden line c. centre line d. dimension line e. extension line f. leader line g. phantom line h. cutting plane line i. section lines j. long break line k. short break line Figure FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

28 theory Competency RK2-1 (Line I-I3) 2. Which lines indicate the exposed surfaces in a sectional view? a. leader lines b. section lines c. cutting plane lines d. phantom lines Answers 3. Which line shows the edges and surface not visible to the eye? a. object line b. phantom line c. invisible line d. hidden line 4. Which line indicates the path of an imaginary cut through the part? a. cutting plane line b. break line c. hidden line d. phantom line 5. Which line shows the visible edges, corners and surfaces in a view? a. dimension line b. leader line c. hidden line d. object lines 6. How are alternate positions of moving parts shown? a. with an object line b. with a hidden line c. with a phantom line d. with a break line 7. Which line shows notes or specifications? a. leader line b. phantom line c. extension line d. object line BC WELDER TRAINING PROGRAM 29

29 theory Competency RK2-1 (Line I-I3) Answers 8. Which line indicates that a part has been reduced in size on a drawing? a. phantom line b. cutting plane line c. break line d. hidden line 9. Which line is used to show the location of a section? a. hidden line b. centre line c. cutting plane line d. reference line 10. Which line is used to eliminate repeated detail? a. dimension line b. break line c. hidden line d. phantom line 11. What does a sectional view normally show? a. outside of a part b. inside dimensions c. only the internal holes and slots d. inside of a part Now go to the Answer Key and check your answers. 30 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

30 theory Competency RK2-1 (Line I-I3) RK2-1 Learning Task 3: Sketch orthographic projections Sketching orthographic views Sketching provides a quick and simple way to express ideas and to communicate the shape and general size of an object to other people. Freehand sketching to approximate scale For freehand sketching you require a pad of sketch paper 216 mm 280 mm with a 5-mm grid (8½ in. 11 in. paper with a ¼-in. grid). You will also need an HB pencil and an eraser. Do not begin any sketch or exercise with a dull pencil. If you are not using an automatic pencil with fine lead, take the time to sharpen your pencil before putting any lines on the paper. This is also a good time to plan your sketch. You have probably heard the expression, It s a scaled-down version. This means, of course, that the object referred to looks smaller than the original, but the proportions of length, width and height are the same. Figure 29 shows a full-size rectangle, as well as half-size and quarter-size versions. Note that they are the same shape. The only difference is that they are smaller. They are scaled-down views of the full-size object. Full size Half size Quarter size Figure 29 Scaling When you are sketching freehand, your sketches should reflect the true shapes of objects as much as possible. If you use grid paper, it is not difficult to sketch to an approximate scale. Assume that the object in Figure 30 is shown full size. BC WELDER TRAINING PROGRAM 31

31 theory Competency RK2-1 (Line I-I3) Figure 30 Full-size pictorial view of object To show all the necessary orthographic projection views on the same sheet of paper, the views must be scaled. Figure 31 shows the views at approximately one-half the original size. DR. I.B. DATE CHK D C.B. DWG.NO. A4-10 Figure 31 Half-size three-view orthographic projection of object The majority of the sketches you will produce will only need to be to an approximate scale. The more accurate the proportions, the easier your sketch will be to interpret. To draw a three-view orthographic projection sketch of an object, it is easiest to draw the front view of your object first and then project the other required views across or up from that view. This is the method used by draftspeople and it makes the job of projecting orthographic projection views much quicker and easier. 32 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

32 theory Competency RK2-1 (Line I-I3) The first step is to select the best choice for the front view. Select the surface that best shows the characteristic shape of the object and avoids hidden surfaces as much as possible. Figure 32 shows an object pictorially along with the best choice for the front view. Figure 32 Pictorial and front views The next step is to extend light projection (extension) lines across to the right and up. All the horizontal lines will be projected to the right and all the vertical lines will be projected upward. (Figure 33). These lines will be used as guidelines for drawing the right-side and top-side views. Figure 33 Projection (extension) lines Sketch the right-side and top-side views in their appropriate places (Figure 34). Be sure to leave enough space between the sketches for future dimensions or notes. Add hidden lines for any features that are not visible in each view. BC WELDER TRAINING PROGRAM 33

33 theory Competency RK2-1 (Line I-I3) Figure 34 Completed three-view orthographic projection sketch Now complete Self-Test 3 and check your answers. 34 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

34 theory Competency RK2-1 (Line I-I3) BC WELDER TRAINING PROGRAM 35

35 theory Competency RK2-1 (Line I-I3) Answers Self-Test 3 Complete the drawings as indicated. Do not be concerned with dimensions. Concentrate on producing good, dark object lines, good circular shapes and correctly drawn hidden and centre lines. 1. Sketch one orthographic projection view of the plate stiffener shown pictorially in Figure 35. Remember that the holes in the plate stiffener are circular, not elliptical as they appear in the three-dimensional sketch shown. Figure 35 Plate stiffener 2. Sketch two orthographic projection views (front-side view and topside view), in approximate scale, of the stop piece shown pictorially in Figure 36. Remember to place the views correctly and make sure that all hidden lines are clearly shown. 36 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

36 theory Competency RK2-1 (Line I-I3) Answers Figure 36 Stop piece Now go to the Answer Key and check your answers. BC WELDER TRAINING PROGRAM 37

37 theory Competency RK2-1 (Line I-I3) 38 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

38 theory Competency RK2-1 (Line I-I3) RK2-1 Learning Task 4: Sketch auxiliary and sectional views Quite often the standard or orthographic projection views are not sufficient to show all the details necessary to fabricate the part. Auxiliary and sectional views are added to show the detail necessary. Auxiliary views Auxiliary views are used to show the slanted surfaces of a part that cannot be clearly shown in any of the standard orthographic projection views. They are drawn in addition to the standard views. These views are drawn as projections from the surfaces they represent in the standard views. Auxiliary views are identified by the standard view from which they are projected. Top-side auxiliary views are projected from the top-side view; front auxiliary views are projected from the front-side view; and right-side auxiliary views are projected from the right-side view. In Figure 37, the auxiliary view has been taken from the front-side view. Figure 37 Front auxiliary view Using auxiliary views also permits the draftsperson to accurately show details, such as holes or slots on angled surfaces. These circular features appear distorted on the angled surface in the principal orthographic projection views. The auxiliary view is necessary to show their true shape. BC WELDER TRAINING PROGRAM 39

39 theory Competency RK2-1 (Line I-I3) The slanted bracket in Figure 38 is a pictorial drawing of a part that would benefit from an auxiliary view. The front-side view of the orthographic projection shows an auxiliary view of the slanted surface. Note that the auxiliary view is placed perpendicular to the slanted surface. Top Auxiliary view Front Right side Section views Figure 38 Orthographic projection with an auxiliary view It is common practice to show much of the detailed technical information with individual section views. A section view is obtained by theoretically cutting through an object or combination of members. To orient the section on a relating view, the plane of the cut is shown by a heavy, broken cutting plane line (Figure 39). Arrows on the ends of cutting plane lines indicate the direction of viewing when the section is drawn (Section A-A in Figure 39). Normally identification letters are used to relate the line to its proper view. A section view does not have any meaning unless it can be oriented properly. A A Cutting plane line Section A-A Figure 39 Orthographic projection showing a section view 40 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

40 theory Competency RK2-1 (Line I-I3) Locating section views A cutting plane line may be shown in any view in the drawing. The arrows at the ends of a cutting plane line indicate the direction of your view when looking at the section drawing. If the cutting plane line points to the left, the part should be viewed as a right-side view. If the cutting plane line points to the right, the sectional view is drawn as a left-side view (Figure 40). A B A B Straight section Offset section Figure 40 Locating section views Showing section views The lines used to indicate the surfaces made by the cutting plane lines are called section lines. Section lines are normally drawn at a 45 angle and are closely spaced to avoid confusing them with other lines on the drawing. When several parts are shown together, general-purpose section lines may be altered to indicate the different parts. Also, section lines can be used to indicate the type of material the object is made from (Figure 41). BC WELDER TRAINING PROGRAM 41

41 theory Competency RK2-1 (Line I-I3) Change spacing and angle mm 45º Change direction Iron and general use Steel Alloys, white metal zinc and lead Magnesium and aluminum Rubber and plastic Bronze, brass and copper Concrete Glass and slate Earth Types of section views Figure 41 Section lines showing types of materials The four basic types of section views commonly shown in welding drawings are full section, half-section, broken section and revolved section. Full sections Full sections (commonly called cross-sections ) are section views that show the internal details of a complete part (Figure 42). In these sections, the cutting plane line is drawn completely through the part. A A Figure 42 Full section 42 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

42 theory Competency RK2-1 (Line I-I3) When section views are placed away from the standard view, they are called removed sections. Removed sections in large drawings are often placed in one area of the drawing or even on a separate sheet. Half-sections Sometimes it is a good idea to develop an orthographic projection that has one view that includes a section view. Usually this is done with objects that are symmetrical or almost symmetrical in shape and where the object has a centre line that can be used to show where the object has been cut. Figure 43 shows an object similar to that shown in Figure 42, but note that only half of the front view has been sectioned. The centre line stands as the dividing line between the half-section and the regular view. Half-sections do not require cutting plane lines, as it is usually obvious where the object has been cut. Top Half-section Figure 43 Half-section Broken sections If only a small portion of an object needs to be shown, a broken or partial section may be used. An important interior construction of a small portion may be shown without full sectioning of the part. Figure 44 shows a broken section for a grinding arbor. The section lines make it easy to see the internal construction of just that part of the object that needs a clear definition. Figure 44 Broken section BC WELDER TRAINING PROGRAM 43

43 theory Competency RK2-1 (Line I-I3) Revolved sections Revolved sections are used mainly in welding drawings to show the shape of a structural metal part. A revolved section is a full sectional view that has been turned 90 from the part it represents. As shown in Figure 45, a revolved section may be placed in a space between break lines, or it may appear as a view placed on top of another view. Figure 45 Revolved section Now complete Self-Test 4 and check your answers. 44 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

44 theory Competency RK2-1 (Line I-I3) BC WELDER TRAINING PROGRAM 45

45 theory Competency RK2-1 (Line I-I3) Answers Self-Test 4 Choose the correct response for each question and put it in the Answers column. Cover your answers when reviewing the test for study purposes. 1. Auxiliary views are often used to show a. phantom surfaces b. slanted surfaces c. parts to be added later d. hidden surfaces 2. Auxiliary views are also especially good for showing a. movable parts b. holes or slots on slanted surfaces c. complex objects d. unassembled parts 3. Auxiliary views are usually shown a. in addition to standard orthographic views b. instead of a top view c. on a separate drawing d. instead of a front view 4. Sketch an auxiliary view that would show surface A of Figure 46. A Top A A Front R ight side Figure FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

46 theory Competency RK2-1 (Line I-I3) 5. Half-sections are ordinarily used on a. non-symmetrical objects b. symmetrical objects c. multipart objects d. multidimensional objects Answers 6. What do arrows on cutting plane lines indicate? a. an offset section b. the location of the imaginary cut c. the direction from which to view the section d. a broken section 7. Section lines are used to indicate the type of material and to a. show the surfaces along the cutting plane b. show a top view c. indicate the dimensions d. indicate the direction of the cutting plane Top Front Figure 47 BC WELDER TRAINING PROGRAM 47

47 theory Competency RK2-1 (Line I-I3) Answers 8. Sketch a full section of Figure 47 through the holes in place of the front view shown below. Show your cutting plane line and label your views. Now go to the Answer Key and check your answers. 48 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

48 Theory Competency RK2-2 (Line I-I3): Sketch isometric drawings of basic objects The following table shows you where information about Level 2 content is covered from the new Harmonized Program Outline (2016). RK2-2 (F & L2) RK2-2 LT1 Pages Level 2 RK2-2 LT2 Pages Level 2 RK2-2 LT3 Pages Level 2

49 theory Competency RK2-2 (Line I-I3) Outcomes There are times when you must convey an idea to someone who is not familiar with orthographic projection, but who can easily understand a pictorial or three-dimensional sketch. There are also times when it is very convenient to be able to develop an idea in three dimensions, especially if the object has many interconnecting parts. Pictorial sketches are often much better for describing items like piping layouts or structural assemblies, which can become very complicated and difficult to understand if drawn by orthographic projection. When you have completed the Learning Tasks in this Theory Competency, you should be able to: identify oblique and isometric drawings describe the principles of isometric drawing make isometric sketches of basic rectangular objects make isometric sketches of basic objects with circular features Evaluation When you have completed all the Theory Competencies in module RK2, you will take a written test. You must score at least 70% on this test. The test will include questions that are based on the following material from Theory Competency RK2-2: pictorial drawings the principles of isometric drawing making isometric sketches of basic rectangular objects making isometric sketches of basic objects with circular features Resources All the resources you will require are contained in this Competency. BC WELDER TRAINING PROGRAM 51

50 52 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

51 theory Competency RK2-2 (Line I-I3) RK2-2 Learning Task 1: Pictorial drawings Pictorial drawings Oblique and isometric sketches are three-dimensional (pictorial) drawings. They are sometimes shown together with an orthographic projection drawing. Very often these pictorial types of drawings are prepared first. From these, orthographic projection drawings are developed. The difference between oblique and isometric drawing is the way in which they appear on the paper (Figure 48). A C C B A 30º 30º B 45º Figure 48 Isometric and oblique drawings In an isometric drawing, no side of the object faces directly toward you. Instead, the three sides appear to recede off at angles. In an oblique drawing, you have a straight-on view of one side of the object. The other two sides recede off at an angle. Oblique sketches offer the advantage of easily showing some objects, but oblique sketches can distort the original object. Isometric drawings Isometric drawings show an object as though it were tipped up toward you. They are a simple means of pictorially presenting the three dimensions all objects have. To correctly construct isometric drawings, you must know basic things about their construction. These distinguishing features enable you to identify isometric drawings as well as to construct them. Isometric means equal measurement. This term applies to the fact that the three axis on which isometric drawings are made are drawn at 120 from each other. Figure 49 shows the three isometric axis. Two of the axis are sketched at 30 to the horizontal. BC WELDER TRAINING PROGRAM 53

52 theory Competency RK2-2 (Line I-I3) 120º 30º 30º Figure 49 Isometric axis All isometric lines are drawn parallel to one of these isometric axis. All lines sketched on one of the two radiating axis will recede to the right or to the left, and all lines that recede in the same direction must be parallel (Figure 50). 30º 30º Figure 50 Isometric lines Another feature of isometric drawing is that all horizontal and vertical measurements on an orthographic projection drawing can be transferred directly to an isometric drawing. In other words, an isometric drawing is made using the actual measurements from either the object itself or from an orthographic projection drawing. Figure 51 shows a cube drawn in orthographic projection and in isometric. Note that when the cube is sketched in isometric, the sides are still equal in length and have the same measurements as the original cube. 54 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

53 theory Competency RK2-2 (Line I-I3) 3 units 3 units 3 units 3 units 3 units Figure 51 Cube in orthographic projection and in isometric You can also see from Figure 51 that hidden lines are not normally shown in isometric drawings. To do so would be extremely difficult, and it would unnecessarily complicate an otherwise clear presentation of an object. Another identifying characteristic of isometric drawings is that holes or other circular details are never drawn as circles. They always become ellipses or parts of an ellipse (Figure 52). They are drawn that way because the features on an isometric drawing are tilted toward you. You do not look directly down on them as you do in orthographic projections. 30º 30º Figure 52 Circular detail in isometric Lines that would not be drawn either vertically or horizontally in orthographic projection (such as angular faces) cannot be drawn on one of the isometric axis. Their angles cannot be established by means of a protractor. In such cases, the lines must be drawn by plotting the points that locate their ends, then joining these points (Figure 53). BC WELDER TRAINING PROGRAM 55

54 theory Competency RK2-2 (Line I-I3) Visualization Figure 53 Angular detail in isometric Visualization is simply a process of studying the views in an orthographic drawing to form a mental picture of how the completed part should actually appear. The easiest way to visualize a part is by using a step-bystep approach. After a little practice with orthographic drawings, you will automatically begin to think in terms of a three-dimensional part rather than in terms of the two-dimensional views. The basic visualization process consists of the following steps: 1. Study the front view of the object to determine the general shape and size of the part. Look for any special details, such as curved surfaces or angles (Figure 54). Figure 54 Determine the general shape from the front view 2. With the front view in mind, study the top view. This step will give you a general idea of the overall appearance of the part (Figure 55). Note the relationship of any unknown details from the front view to the top view. 56 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

55 theory Competency RK2-2 (Line I-I3) Figure 55 Overall appearance as seen from front and top views 3. Again, with the front and top views in mind, study the right-side view. This view will normally clarify any unknown details and make the overall appearance of the part easier to visualize (Figure 56). Figure 56 Complete the process by adding information from the right-side view Now complete Self-Test 1 and check your answers. BC WELDER TRAINING PROGRAM 57

56 theory Competency RK2-2 (Line I-I3) Answers Self-Test 1 Choose the correct response for each question and put it in the Answers column. Cover your answers when reviewing the test for study purposes. 1. Select the figures that illustrate isometric drawings. a b c d 2. At what angle to the horizontal are isometric axis drawn? a. 30 b. 90 c. 130 d How do circles appear in isometric drawings? a. as perfect rounds b. only half-circles can be shown c. as ovals d. as ellipses 4. In isometric sketches, which view faces directly toward you? a. side view b. front view c. top view d. no view directly faces you Now go to the Answer Key and check your answers. 58 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

57 theory Competency RK2-2 (Line I-I3) RK2-2 Learning Task 2: Sketch isometric drawings of basic objects Sketching simple rectangular objects The easiest object to sketch is a solid block that has dimensions of length (L), width (W) and depth (D). There are four basic steps to be followed when producing an isometric sketch: 1. Draw a Y-shaped axis on your grid paper. The sloping axis should be drawn at an angle of 30 from the horizontal grid line. In Figure 57A, you can see that if the vertical axis of the Y indicates the depth (D), the two sloping axis will indicate the length (L) and the width (W). Length Width 30º 30º L W 30º 1 unit Depth D A 2 units B Figure 57 Step 1 Note that you can draw an angle of about 30 by sketching lines that run two spaces horizontally and one space vertically (Figure 57B). 2. Once you have located the measurements for L, W and D, sketch the top of the block by drawing two parallel lines: one parallel to L and one parallel to W (Figure 58). You should begin with light construction lines so that you can make any necessary adjustments before darkening them. BC WELDER TRAINING PROGRAM 59

58 theory Competency RK2-2 (Line I-I3) Isometric view of the top surface of the rectangular block L W D Figure 58 Step 2 3. Sketch a second line parallel to L and another line parallel to D (Figure 59). This completes the front surface. Top surface Front surface L W D Figure 59 Step 3 4. Sketch two lines parallel to W and D. This completes the outline of the rectangular block (Figure 60). 60 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

59 theory Competency RK2-2 (Line I-I3) Top surface Front surface L W Right side D Figure 60 Step 4 The finished isometric sketch is shown in Figure 61. Top Front L W Right D Figure 61 Completed isometric Sketching figures with isometric lines Not all rectangular objects are as simple as the rectangular block. Sometimes the shapes are irregular and have cut-out sections or some sides longer than others. All rectangular objects can be fitted exactly into a box that is drawn to the object s maximum length (L), width (W) and depth (D). This means that you can always begin by sketching a light outline of a basic box that suits the size of the object to be drawn. As an example, look at the object shown in the three-view orthographic projection sketch in Figure 62. To produce an isometric sketch of this object, you need to find the maximum L, W and D for the containing box. In this case: L = 5 grid spaces W = 3 grid spaces D = 4 grid spaces BC WELDER TRAINING PROGRAM 61

60 theory Competency RK2-2 (Line I-I3) Top-side W = 3 units L = 5 units Front-side Right-side D = 4 units Figure 62 Orthographic projection views To draw an isometric of this object, work through the following steps: 1. Sketch a light isometric outline of the basic rectangular box to the required size (Figure 63). Top-side surface D = 4 units Front-side surface L = 5 units Right-side surface W = 3 units Figure 63 Step 1: Basic isometric box outline 2. Establish the outline of the main features. The front view shows the outline most clearly. Place this view on the front surface of the isometric box. Use the dimension given in the front view of Figure 62 and mark the number of units along the axis L and D (Figure 64). 62 FOUNDATION AND APPRENTICESHIP LEVELS 1 AND 2

61 theory Competency RK2-2 (Line I-I3) 1 unit 3 units 1 unit 1 unit 2 units 1 unit Figure 64 Step 2: Location of steps on axis 3. Lightly sketch lines parallel to the L and D axis from the marked points on the front surface. The step outline is drawn more heavily to emphasize the profile of the object once you are sure your sketch is correct (Figure 65). Top-side surface L W Step outline D Right-side surface Front-side surface Basic block Figure 65 Step 3: Location of main features 4. The step outline in Figure 65 intersects axis L and D. These two points locate the top and right-side surfaces that meet the top and right-sides of the basic block. Draw in lines parallel to W as shown in Figure 66. BC WELDER TRAINING PROGRAM 63