AUR30405 CERTIFICATE III IN AUTOMOTIVE MECHANICAL TECHNOLOGY

Transcription

1 AUR30405 CERTIFICATE III IN AUTOMOTIVE MECHANICAL TECHNOLOGY AURT225667A Use and maintain measuring equipment - Part 1 LEARNER WORKBOOK Version 1: August 2010 Learner s Information and Activity Workbook

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3 ISBN: This document is available under a Free for Education licence for educational purposes see for details. This work is copyright. You may download, display, print and reproduce this material in whole or in part or in modified form (retaining this notice) for your personal, non commercial use or use within your organisation. If you use, display, or reproduce this material or a modified form of it in whole or in part within your organisation you must include the following words in a prominent location within the material in font not less than size 12: The views expressed in this publication do not necessarily represent the view of the Minister for Education or the Australian Government. The Australian Government does not give any warranty nor accept any liability in relation to the contents of this work. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. Requests and inquiries concerning reproduction and rights should be addressed to the Commonwealth Copyright Administration, Attorney General s Department, Robert Garran Offices, National Circuit, Barton ACT 2600 or posted at Funded under the Workplace English Language and Literacy (WELL) Program by the Australian Government Department of Education, Employment and Workplace Relations. The views expressed in this publication do not necessarily represent the view of the Minister for Education or the Australian Government. The Australian Government does not give any warranty nor accept any liability in relation to the contents of this work.

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5 AURT225667A Use and maintain measuring equipment 1 Elements... 1 About the workbook... 1 Assessment... 3 Skills Recognition... 4 Access and equity... 4 Introduction to measuring 5 Measuring accurately... 5 Manual lifting safety... 8 Feeler gauges 10 Flat type Wire type Straight Edge Activity Callipers and rules 17 Steel rules Simple callipers Caring for callipers Callipers with sliding jaws Dial-type callipers Digital callipers Vernier callipers Reading the Vernier scale Activity Activity Activity Micrometers 42 Overview Parts of a micrometer Caring for micrometers Outside micrometer Other micrometers Using the conventional outside micrometer Reading the micrometer scale Activity Activity

6 Dial indicator gauge 56 Setting up the dial gauge Reading a dial gauge Digital dial-type indicator Activity Activity Activity Glossary 71

7 1 AURT225667A Use and maintain measuring equipment This unit covers the skills needed to use and keep in good condition measuring equipment used in the general automotive repair trades. The unit includes: identifying and confirming work requirements preparing for work making measurements analysing and documenting outcomes maintaining equipment and finishing off work, including clean up documentation. Elements 1. Prepare to undertake measurements. 2. Conduct measurements and analyse results. 3. Maintain measuring equipment. About the workbook This workbook will help you to: learn the names of different types of measuring tools learn what they are used for, and how they are used make measurements with these tools to the level required by the competency standard Use and Maintain Measuring Equipment. This workbook gives you information, questions to answer, and practical jobs for you to do. The book tells you where to find extra information if you need it. The workbook is divided into stages. At the end of each stage, you are asked to check your answers and practical activities with your teacher, so that you can both keep track of your progress.

8 What do the icons mean? An icon is a picture with a meaning. In the workbook, these icons tell you something about: what to do next (activity, check your answers, watch a video clip) or the text (this is a safety warning). Complete an activity Check your answers with your trainer Watch this video clip Safety warning 2

9 3 Assessment To meet the assessment requirements for this competency standard you must demonstrate the following: Knowledge of: OH&S regulations/requirements, equipment, material and personal safety requirements common automotive measurement terminology types of non specialist measuring equipment and their applications how to make measurements measuring equipment maintenance procedures workplace quality procedures how your workplace organises its work. Practical ability to: work safely and take notice of safety procedures communicate clearly with other people about your measuring tasks choose methods and techniques suitable for the measuring tasks given to you carry out any work that is needed before measuring can take place in a systematic way for example, dismantling an engine before measuring the crankshaft measure dimensions or quantities using the instruments listed in the range statement take good care of measuring equipment measure items in a way which suits your workplace use measurements to help you decide on suitable repair processes make measurements within the time allowed by the workplace.

10 Skills Recognition You may already have knowledge and skills for all (or part) of this competency standard. If you believe you can demonstrate that you already have the skills and knowledge required, talk to your trainer about applying for Skills Recognition. This is also known as Recognition of Prior Learning (RPL), Recognition of Current competence (RCC), or simply Recognition. Skills Recognition is a process for gaining credit for those skills and knowledge gained through work experience, formal training or other life experience. Access and equity In training, access and equity means ensuring that people with differing needs and abilities have the same opportunities to successfully gain skills, knowledge and experience through education and training. It is about removing barriers and providing the supports people need to access, participate and achieve, irrespective of their age, disability, colour, race, gender, religion, sexuality, family responsibilities or location. For students with disabilities, training organisations may make adjustments to ensure equal opportunity. Reasonable adjustments are designed to minimise the disadvantage experienced by learners with a disability and can include administrative, physical or procedural modifications. NOTE: If you believe you could benefit from support to help you overcome a barrier to participation, you should speak to your trainer or the person in your RTO responsible for access and equity. 4

11 5 Introduction to measuring Measuring and checking are two of the most important procedures that are performed in an automotive workshop, and they must be done accurately. In most types of mechanical service or repair, some type of measurement is taken or a check is made of the size, fit, clearance, pressure or other specification. For example, we use measuring instruments to check and adjust spark plug gaps, measure brake disc thickness and measure valve tappet clearances. Figure 1: Adjusting tappet clearance, OHC engine Measuring accurately To measure accurately you must learn to: handle and use measuring tools correctly select measuring tools that are suitable for the work check that the measuring tool is reading accurately. Measuring tools will not be accurate if they are damaged by dropping, by abuse, or by mishandling. Sensitive measuring instruments can read dimensions as small as 0.1 mm or less. They can be damaged or put out of adjustment by unskilled or careless handling. They must be checked often to make sure they are still giving accurate readings.

12 Measuring equipment covered in this resource includes: 1. Feeler gauge 2. Straight edge 3. Steel rule 4. Callipers 5. Vernier calliper 6. Outside micrometer 7. Dial indicator Figure 2: Measuring equipment 6

13 7 Measuring equipment covered in this resource includes: 8. Digital thermometer 9. Multi meter (Amps, Volts, Ohms) 10. Dial thermometer 11. Pressure gauge Figure 3: Measuring equipment

14 Manual lifting safety Measuring sometimes involves working with heavy and awkward shaped machinery. Cylinder heads, cylinder blocks and crankshafts are heavy to lift and can roll or fall off the bench, crushing hands and feet. Figure 4: A cylinder head supported on suitable stands 20+kg Figure 5: A cylinder block 50+kg Figure 6: A crankshaft 20+kg 8

15 9 Use stands, chocks or V blocks to ensure components cannot roll or move when you are measuring. Otherwise you may be injured or the component may be damaged. Figure 7: V blocks holding a crankshaft Observe all occupational health and safety requirements when lifting or moving heavy components. When you need to lift, get somebody to help you. Better still, use properly designed lifting equipment such as cranes or block and tackles. Ask for help and some instruction if you need to use lifting equipment that you haven t used before. Figure 8: Hoists must be used for lifting heavy equipment

16 Feeler gauges There are two types of feeler gauges, the flat type and the round wire type. Flat type Figure 9: Feeler gauge flat type The flat type consists of hardened steel blades of various thicknesses. Each blade is marked with its size in millimetres and/or inches. Figure 10: Adjusting tappet clearance, OHV engine It is useful for measuring small slots, gaps or grooves, for example, valve or tappet clearance. 10

17 11 Wire type Figure 11: Spark plug gauge The wire type gauge is designed for checking and adjusting spark plug gaps. It consists of several wires with different diameters. It also has a gap adjuster to safely adjust the spark plug gap by bending the earth electrode on the spark plug. Care Figure 12: Checking clearances with feeler gauges Use feeler gauges carefully to avoid damaging the blades. The blade should slide easily and not be forced. If it gets bent or kinked, it is useless. Use extra care with the thinner blades. After use, wipe the strips clean with a clean oily cloth. This will stop them from rusting, and allow the size marking to be seen easily Store in a clean, dry place.

18 Straight Edge The common straight edge is: made from a thick wide strip of alloy steel hardened and ground to form two parallel flat edges usually between 150mm to 1000mm in length. Figure 13: Straight Edge Use The straight edge is used to check the flatness of a surface. To check a cylinder head for flatness: Place the edge of the straight edge on the cylinder head surface. Then use a feeler gauge to check for any gap or distortion (bend) between the straight edge and the surface of the head. Figure 14: Testing the head face for distortion 12

19 13 Care Figure 15: Testing the manifold mounting face for distortion A straight edge is a precision tool and must be carefully handled. If you drop, strike or bend it, the tool will be inaccurate and useless. Immediately after use, wipe the straight edge clean with a clean lightly oiled rag. Store on a hook on the wall.

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21 15 Activity 1 Tick the correct answer(s). Question 1 Heavy machinery should be lifted: by two people sharing the load. by yourself. by engine hoist or crane. by the boss. Question 2 If you need to operate equipment but you have no experience or training for it, you should: give it a go by yourself. ask for help, training or guidance. sit down and wait for help. Question 3 The two common types of feeler gauges are (tick TWO): flat blade type serrated blade type spiral wire type wire type. Question 4 Select from the following the correct feeler gauge for these TWO measuring jobs. Write your answer next to each task. flat blade type serrated blade type spiral blade type wire type TASK 1: Measuring a spark plug gap: TASK 2: Measuring valve clearances:

22 Question 5 To take care of a feeler gauge: wipe it clean file it smooth hammer it flat coat it lightly with oil. Question 6 Circle the correct word: When using a feeler gauge to measure a small gap, the blade should be pulled / pushed through the gap. Question 7 A feeler gauge and a straight edge can be used to measure: angles in a steering arm bend in a wheel rim distortion in a flat surface taper in an oval axle shaft. Question 8 To keep a straight edge in good condition: clean it with abrasive paper hang it on a hook on the wall file its edges straight after every use wipe it clean with an oily rag clamp it tightly in a vice. Ask your trainer to check your results before proceeding. Trainer Signature:... Date:... 16

23 17 Callipers and rules Steel rules Steel rules are used for general measurements. Steel rules are usually 150mm, 300mm or 600 mm in length and are graduated in millimetres and centimetres. Some rules have millimetres on one side and inches on the other. Care Figure 16: Steel rule Steel rules must be handled carefully. The zero end must be kept in perfect condition to maintain accuracy. Inspect the end of the rule to make sure it is not rounded at the corners or has not been shortened by grinding. After use, wipe clean and place on tool board. Figure 17: Inspect end of rule

24 Measuring with a steel rule Steel rules are used to measure to an accuracy of 1mm. Where more accurate readings are necessary, you should use different measuring tools discussed later in this resource. Some rules can measure to an accuracy of 0.05mm. Steel rules can be used in many situations, for example: to measure a certain distance in order to drill a hole to measure the size of material to be cut. To measure the length of a piece of material: 1. Stand the rule on its edge. 2. Place the end of the rule flush (exactly in line) with the starting point of the material. Figure 18: Measuring with a rule 3. Look carefully at the exact place on the rule where the material finishing point occurs 4. Read the scale at the point where the material finishes. The smallest graduations are usually 1mm. There are bigger markings every 5mm and 10mm /1cm (see Figure 16). 18

25 19 Simple callipers Callipers are measuring tools which have two adjustable legs or jaws. The jaws or legs are adjusted to fit the component being measured. They are used to measure the diameter of holes, or the distance between two surfaces. Simple callipers have two legs and can be inside or outside callipers. They do not have a scale, and must be used with a steel rule to read the dimension (size) of the component. They are rarely used any more. Figure 19 Inside and outside leg callipers Caring for callipers To protect callipers from damage: Keep them in their own protective case or box. Never keep them loose in a toolbox with other tools. Never drop the calliper, or give it sharp shocks. Never apply excessive force to the calliper when measuring. Clean metal parts with a slightly oily rag. Clean plastic parts with a dry rag. Inspect jaws and legs regularly for damage which would make the calliper less accurate. Replace batteries regularly in digital callipers.

26 Callipers with sliding jaws Sliding jaw callipers are often used in the automotive industry. They have their own measuring scales built into the instrument. They are accurate to hundredths of a millimetre. They can measure outside or inside, and length, width, height or diameter. Common types are: 1. Dial type callipers 2. Digital type callipers 3. Vernier callipers. Figure 20: Dial type calliper Figure 21: Digital calliper Figure 22: Vernier calliper 20

27 21 Dial-type callipers This is a type of Vernier calliper which has a measuring dial mounted on it. Metric dial callipers can read down to 0.01 mm. This is the smallest amount it can read, and is called the resolution of the measuring instrument. Some other dial callipers have a resolution of 0.02 mm. Figure 23: Dial type calliper parts You may need to zero the calliper, or set it to read zero when the jaws are fully closed. To do this, loosen the locking screw and rotate (turn) the dial face. Using the dial-type calliper STEPS DONE 1. Clean the jaws and close them. Check that no light is visible through them. 2. Check the dial pointer is exactly on zero. Zero the dial if necessary. 3. Open the jaws and then gently close them on the part being measured. Adjust the jaws to get the correct feel just a slight drag. 4. Tighten the slide locking screw. 5. Read the number of whole millimetres (just to the left of the dial face). 6. Read the number of hundredths of a millimetre shown by the dial pointer. 7. Add the dial reading to the whole millimetre reading this gives the total measurement.

28 Digital callipers The digital calliper has jaws which slide on the main frame, just like the other sliding jaw callipers. The jaws can make inside and outside measurements. The calliper also has a depth gauge. Measurements are shown on a small electronic display attached to the sliding jaw. Most digital callipers can display measurements down to 0.001mm (one thousandth of a millimetre). This is called the resolution of the display. The digital calliper can display both metric and imperial (inch) measurements, by pressing the correct button. Digital callipers must be set to ZERO before each use: 1. Clean and close the jaws. Press the ON button. 2. Check that no light is showing between the jaws. 3. Press the ZERO button on the calliper. 4. Check that the display reads zero. Figure 24: Digital calliper 22

29 23 Using the digital calliper STEPS DONE 1. Clean the jaws and close them. Check to see that no light is visible through them. 2. Press the mm button on the calliper, to measure millimetres. 3. Press the ZERO button on the calliper. 4. Open the jaws and gently close them on the part being measured. Adjust the jaws to get the correct feel just a slight drag. Tighten the slide locking screw. 5. Read the measurement from the digital display. Example This calliper has taken a measurement of mm. Figure 25: Digital disc brake calliper It is measured with a special calliper, with extra long jaws.

30 Vernier callipers The Vernier calliper external jaws can measure outside diameters, inside diameters thickness and length. This one is being used to make measurements for replacing a valve seat insert in a cylinder head. External jaws can be used to measure external diameters. Figure 26: Measuring the outside diameter Internal jaws can be used to measure gaps and internal diameters. Figure 27: Measuring inside diameter The depth gauge measures steps, heights, and the depth of holes or recesses. Figure 28: Measuring depth 24

31 25 Reading the Vernier scale A Vernier calliper has two scales a main scale and a Vernier scale. The main scale is marked on the frame of the calliper. It is marked in millimetres, just like an ordinary rule. The Vernier scale is marked on the sliding jaw of the calliper. It is marked in fractions of a millimetre. Figure 29: Parts of the Vernier calliper Figure 30: Vernier scale This Vernier scale has 50 divisions. Each division, or graduation, represents 0.02 mm. This is 2/100 of a mm or two hundredths of a millimetre. This is the resolution (smallest graduation) for this Vernier. Other Verniers may only measure to 0.05mm.

32 Before you measure Before use, check that when the jaws are closed, the main scale zero marks lines up exactly with the Vernier zero mark. Figure 31: Checking accuracy of a Vernier calliper Accurate measuring with a Vernier calliper takes practice. It is important to get the right feel when you measure something. The jaws should not be too tight or too loose sometimes it helps to gently rock the jaws as you adjust them. Never force the jaws closed. Lock the jaws after taking a measurement, so that the setting doesn t change accidentally. Then double check the setting. Figure 32: Measuring 26

33 27 Read the main scale measurement There are three steps in reading the Vernier calliper: 1. Read the main scale 2. Read the Vernier scale 3. Add the two measurements together. As the jaws are opened, the Vernier zero moves away from the main scale zero. The size of the first measurement is the distance between the two zero marks. This measurement is in whole millimetres. Note it down. Figure 33: Measuring with a Vernier calliper In the example below, the jaws are open just a little bit more than 27 millimetres. The number of whole millimetres shown is 27. You would write down 27 mm. Figure 41: Reading whole millimetres

34 In this diagram, the opening is between 13 and 14mm. The number of whole millimetres shown is 13. Figure 34: Reading 13 whole millimetres 28

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36 Activity 2 Look at these Vernier calliper diagrams. Write down the number of whole millimetres shown in each diagram. Figure 35: Activity 3 examples Ask your trainer to check your results before proceeding. Trainer Signature:... Date:... 30

37 31 Read the Vernier scale measurement The next step is to read the Vernier scale. This will tell you the extra measurement on top of the whole millimetres, to the nearest 0.02 of a millimetre (0.02mm). Figure 36: Reading parts of a millimetre The Vernier scale represents one single millimetre. It is numbered from 0 to 10. Each numbered division represents 0.1 mm, or 1/10 of a millimetre. There are 5 smaller graduations inside each numbered section. This is 50 graduations altogether (5 in each of 10 sections 5 x 10 = 50). Each graduation represents 0.02 mm, or two hundredths of a millimetre. If you count each graduation as 2 (2 hundredths of a mm, or 0.02 mm), the whole scale will add up to 100 (100 hundredths of a mm, or 1.00 millimetre). Figure 37: Each division equals.02mm

38 Example The main scale measurement in Figure 38 below is between 66 and 67 millimetres the measurement is 66 point something. You need to find out what that point something is, so that you can add it to the 66 whole millimetres. Figure 38: Reading parts of a millimetre Line up the graduations Look very carefully along the Vernier scale graduations until you find a Vernier graduation which lines up exactly with a main scale graduation. Figure 39: Looking for graduation alignment 32

39 33 The following diagram shows what this alignment (lining up) of graduations should look like. Figure 40: Alignment of graduations Value of the Vernier reading To find the value of the lined up Vernier graduation, count by 2s along the Vernier scale. This allows you to read the exact measurement as a decimal fraction, straight off the scale. Figure 41: Reading Vernier scale In our example, the number of the lined up graduation is 78. You should read this as point 78 that is, the Vernier reading is 0.78mm. Figure 42: Vernier scale reads 0.78 mm

40 Add the two readings together Figure 43: Total reading of 66.78mm The main scale measurement PLUS the Vernier scale measurement The total measurement mm mm = mm Another example The main scale measurement PLUS the Vernier scale measurement The total measurement mm mm = mm Figure 44: Total reading of 43.24mm If the first and last graduations BOTH LINE UP EXACTLY with the main scale graduations the Vernier scale measurement is 0 or ZERO. The total measurement is an exact number of whole millimetres. 34

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42 Activity 3 Question 1 Look at these Vernier calliper diagrams. The lined up graduations have been marked with arrow heads. Mark an arrow to show the main scale measurement. Write down each total measurement in the boxes above the callipers. Figure 45: Question 1 examples 36

43 37 Question 2 Name the parts of the Vernier calliper. Figure 46: The parts of a Vernier calliper Question 3 What are TWO important rules for taking care of callipers? Write in your own words.

44 Question 4 Tick the correct statement/s in the list below: Sliding calliper jaws should be checked for damage. Metal parts of sliding jaw callipers should be cleaned with a lightly oiled rag. Plastic calliper parts should be cleaned with a dry rag. Brake fluid is a good cleaning agent for callipers. Digital callipers must be set to zero before use. Question 5 Tick the right answer/s: Batteries in digital callipers should be replaced: Regularly, before you have trouble reading the measurement. Only when you can t read the display. Ask your trainer to check your results before proceeding. Trainer Signature:... Date:... 38

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46 Activity 4 This activity will allow you to develop practical skills in measuring with Vernier callipers. Use a Vernier calliper to measure outside, inside and depth of a component. Ask your trainer for a suitable component to measure. Record your measurements below. Inside Diameter Outside Diameter Depth Measurement Ask your trainer to check your results before proceeding. Trainer Signature:... Date:... 40

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48 Micrometers Overview Micrometers are measuring instruments that enable very accurate and precise measurements to be taken. They may be conventional (mechanical, not digital) with engraved graduations, or they may be digital. There are three types of micrometers: 1. the outside micrometer 2. the inside micrometer 3. the depth micrometer. While these micrometers don t look the same, conventional micrometers all use the principle of the micrometer scale. Outside micrometer This measures the width and length of objects. It is used where precise measurements are required e.g. reconditioning an engine, measuring pistons, valves or crankshafts. Figure 47: The common outside micrometer 42

49 43 Inside micrometer The inside micrometer accurately measures the inside of holes or bores. Measurements can be made of the cylinder bore and bearing tunnels. Figure 48: Using an extended handle when measuring a small deep bore Depth micrometer The depth micrometer measures the depth of holes, grooves, recesses and the heights of shoulders. Figure 49: Depth micrometer

50 Parts of a micrometer Figure 50: Parts of an outside micrometer Caring for micrometers Micrometers are precision instruments and they should be used and treated well to remain accurate. Follow these guidelines to keep your micrometer accurate. Clean the face of spindle and anvil. Check the zero reading before using. Don t use it on dirty or rough components. Do not adjust micrometers unless trained to do so. After use, clean it, lightly oil it, and store in a protective box. Store the micrometer with a small gap between the anvil and the spindle. 44

51 45 Outside micrometer The operating range of a micrometer is marked on the frame. It describes the minimum and maximum distance it can measure. The micrometer in Fig. 57 can measure between zero and twenty five millimetres (0 25 mm), and can measure to an accuracy of one hundredth of a millimetre (0.01 mm). Figure 51: Outside micrometer This makes it useful to accurately measure the distance between two machined surfaces, for example the thickness of a shim washer or the diameter of a valve stem. Other outside micrometers may have ranges of 25 50mm, 50 75mm, mm and so on. The spindle and anvil do not meet in these micrometers. Figure 52: 25 mm 50 mm micrometer The accuracy of these micrometers must be checked with special, very accurate distance pieces. These distance pieces are used to check that the micrometer reads zero when the distance piece is tested. Figure 53: Distance (test) pieces

52 Other micrometers Here are some more micrometers that you might use in your work: Vernier Micrometers This micrometer looks similar to the conventional type of micrometer, but it has an extra Vernier scale on the sleeve. The Vernier scale increases the resolution of the micrometer. You can measure down to onethousandth of a millimetre (0.001 mm) with this type of micrometer. If you have one of these micrometers in your workshop, ask your supervisor to show you how to read it. Digital Micrometer Digital micrometers have a digital display attached to the frame. This shows the measurement directly. There is no need to calculate, or add up numbers. Digital micrometers can switch between metric or imperial measurements on the same display. A metric digital micrometer usually has a resolution of 0.001mm. Some digital micrometers have a conventional scale as well as the digital display. Like all digital instruments, digital micrometers must be handled gently. They must be kept dry and clean, and the batteries should be replaced regularly to keep them reliable. 46

53 47 Using the conventional outside micrometer Hold the micrometer by the frame with your left hand. Keep the scale facing towards you. Loosen the spindle lock and undo the thimble with your right hand. Clean the anvils with a clean cloth. Figure 54: Opening the anvils to allow for cleaning Checking the accuracy of the 0-25 mm micrometer Gently screw the thimble inwards (by the ratchet if fitted) until the anvils are touching. Look at the scales they should both read zero. Figure 55: Checking micrometer accuracy Use distance pieces to check the accuracy of outside micrometers with ranges bigger that 25mm.

54 Reading the micrometer scale Open the anvils by turning the thimble to uncover one division. One division equals a reading of 0.01mm. Figure 56: Each division on thimble equals 0.01mm Continue turning the thimble until the tenth line of the thimble is level with the datum (reference) line. Figure 57: Scale on sleeve Hold the micrometer up to the light. The small gap between the anvils is 0.1 mm. Figure 58: Measurement of 0.1 mm 48

55 49 Continue turning until the fiftieth line of the thimble is level with the datum line. - The anvil gap will now be half a millimetre (0.5 mm). - The first lower graduation on the sleeve is now visible. Figure 59: Measurement of 0.5 mm Continue turning the thimble one more complete turn. - The anvils are now open 1 millimetre (1 mm). - The first upper graduation on the sleeve is now visible. Figure 60: Measurement of 1mm Measuring with a micrometer The total measurement on a metric micrometer is made up of: the number of whole millimetres shown on the datum line PLUS half a millimetre IF shown on the datum line PLUS the number of thimble divisions lined up with the datum line.

56 Example measurement 1 Step A Count the number of whole millimetres that are completely visible = 4 mm. Figure 61: Reading 4 whole millimetres (4mm) Step B Count any half millimetres that are completely visible = 0.5 mm. Add to the whole millimetres, like this: 4.0 mm mm = 4.5 mm Figure 62: Read one minor division (0.5 mm) Step C The fifth line on the thimble is lined up with the datum line. This equals 0.05mm. Add this to the 4.5 mm, like this: 4.50 mm mm = 4.55 mm Figure 63: Measurement reading of 4.55mm 50

57 51 Example measurement 2 Step A The whole millimetre scale shows 5 = 5 mm. Step B There is also a 0.5 mm graduation showing. Step C The twelfth line on the thimble scale is lined up with the datum line which equals 0.12 mm. Add these together: Whole mm 5.00 Half mm Hundredths of mm Total measurement = 5.62 mm Figure 64: Measurement of 5.62mm

58 Activity 5 Question 1 Name the parts of the micrometer. Figure 65: The parts of an outside micrometer Question 2 Draw lines to match each measuring task with a suitable micrometer. TASK Measure the distance to the bottom of a groove Measure diameter of an engine piston Measure the diameter of an engine cylinder bore MICROMETER Outside micrometer Inside micrometer Depth micrometer 52

59 53 Question 3 Tick the correct answer(s). Before taking a measurement with a micrometer, you should... rotate the ratchet clean the anvils grease the threads check the accuracy modulate the datum line. Question 4 Record the measurements shown in the following diagrams. Figure 66: Question 4 examples Ask your trainer to check your results before proceeding. Trainer Signature:... Date:...

60 Activity 6 Ask your trainer to select 4 components to measure. List each component in the left hand column. Record the measurements in the right hand column. Components Measurement Ask your trainer to check your results before proceeding. Trainer Signature:... Date:... 54

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62 Dial indicator gauge This is often called a dial gauge or dial indicator. A dial gauge has a face or dial that is marked in divisions of 0.01 mm (one hundredth of a millimetre). The dial gauge does not take a direct measurement, but shows variations from the original zero setting. These variations are transferred from the spindle to the pointer. Figure 67: Dial indicator gauge A dial indicator is always used with a supporting tool. A magnetic stand is commonly used when measuring automotive parts. A clamp type mounting can also be used. Figure 68: Magnetic stand 56

63 57 A dial gauge can be used to measure bends in shafts, run out and flatness. Figure 69: Checking crankshaft alignment The dial gauge can also measure clearance of movement between parts e.g. valve stem to valve guide clearance. Figure 70: Measuring clearance valve stem to guide

64 Setting up the dial gauge Position the dial gauge spindle perpendicular (at right angles) to the surface. Figure 71: Spindle must be perpendicular to surface For accurate readings: the dial gauge must be firmly attached to the magnetic stand the magnetic stand must be securely and firmly mounted on the assembly being measured. The magnetic stand must be securely and firmly mounted to prevent the dial gauge from damage due to dropping or excessive vibration. Figure 72: Eliminate vibration by correct mounting 58

65 59 Reading a dial gauge Watch this video clip: Dial indicator gauge Figure 73: Parts of the dial gauge The outer scale is almost always movable you can rotate the scale to put the zero marker wherever you want it. This is helpful when you want to make an absolute measurement, such as the total lift of a camshaft. Most measurements made with a dial indicator in the automotive industry are relative, or comparison measurements. These are measurements of the variation of some dimensions. Examples are brake disc run out (wobble) or crankshaft end float. There is no need to zero the gauge for most of these measurements you only need to record the variation (swing) of the needle from its first position.

66 Reading the dial gauge To read the dial gauge you must take the readings in the following order: Step 1 Step 2 Step 3 Read the whole millimetres from the small dial (only for absolute measurements). Read the tenths of millimetres from the large dial (each numbered division). Read the hundredths of millimetres from the large dial (each small division). Example 1 Step 1 Read the whole millimetres. The short needle is between the 4 and the 5, so the reading is 4 mm. Figure 74: Reading whole millimetres 60

67 61 Step 2 Read the tenths of millimetres. The long needle is between 0.2 and 0.3 mm, so the reading is 0.2 mm. Figure 75: Reading tenths of a millimetre Step 3 Read the hundredths of millimetres. The long needle is 6 small divisions past the 2, so the reading is 0.06 mm. Figure 76: Reading hundredths of a millimetre Now add the three steps together: Step Step Step Total reading is = 4.26 mm

68 Example 2 Step 1 Whole mm 9.00 Step 2 10th mm Step 3 100th mm Total reading is = 9.85 Figure 77: Measurement of 9.85mm 62

69 63 Digital dial-type indicator Like the micrometer and the Vernier, there are digital versions of the conventional (standard / common / mechanical) dial indicator. They do the same jobs as the conventional dial indicator. They have the advantage that the measurement is shown directly on the display, and they can be switched from metric to imperial (inch) measurements if necessary. Fig 78: Digital indicator The digital indicator can be zeroed before making measurements. When and how this is done depends on the sort of measurement being made. If you have a digital indicator in your workshop, ask your supervisor to show you how to use it.

70 Activity 7 Answer the following questions. Question 1 Tick the answer which describes your gauge. Inspect the metric dial gauge in your workshop. What is the smallest division readable on the gauge? mm 0.01 mm 0.5 mm 0.1 mm 1.0mm Question 2 Tick the answer which describes your gauge. Inspect the metric dial gauge in your workshop. What is the range of this gauge? 1 mm 5 mm 10 mm 100 mm Question 3 Tick the correct answer. Dial indicator gauges must be placed on a flat, even surface. True False Question 4 Tick the correct answer. Which of these actions could damage a dial indicator? Dropping Knocking against heavy components Storing in a protective box Operating the spindle roughly by hand Trying to take a measurement which is greater than the range of the gauge Cleaning with a lightly oiled rag. 64

71 65 Question 5 Record the readings of the following dial gauges.

72 Figure 79: Question 5 examples Ask your trainer to check your results before proceeding. Trainer Signature:... Date:... 66

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74 Activity 8 Ask your trainer to select 4 components to measure. List each component in the left hand column. Record the measurements in the right hand column. Components Measurement Ask your trainer to check your results before proceeding. Trainer Signature:... Date:... 68

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76 Activity 9 This activity involves the checking and maintenance of measuring equipment. Obtain the following measuring equipment: micrometer Vernier calliper rule. Step 1 Check the condition and accuracy of the three measuring devices. Record your findings in the following table. Measuring Equipment Condition Accuracy Micrometer Vernier calliper Rule Step 2 Use appropriate cleaning equipment (clean rag and light oil) to carefully clean the equipment. Ask your trainer to check your results before proceeding. Trainer Signature:... Date:... 70

77 71 Glossary WORD accurate (say: ak ye ret) abrasive adjust alignment arc block and tackle bore clockwise MEANING Exactly right Rough, scratchy Change to give the best fit Exactly in line Curve A system of pulleys with rope or cable, used to lift heavy loads The width of the inside of a cylinder e.g. A piston cylinder The direction the hands move on a clock clockwise snti-clockwise component conventional cylinder (say: sill in der) Part Mechanical, not digital; also traditional A solid shape datum line Reference line that you measure from decimal fraction Tenths eg 0.1 Hundredths eg 0.01 Thousandths eg diameter The distance from one side of a circle to the other side, passing through the centre digital Electronic not mechanical

78 WORD dimension distortion external flush with gauge (say: gaje) graduated graduations guidance imperial measurements internal metric measurements parallel MEANING Size can be length, width, height or diameter Bent out of the correct shape Outside Exactly in line with A measuring instrument Marked or divided into equal sections Equal divisions on a measuring scale Help, advice Feet, inches Inside Metres, centimetres, millimetres Two long edges are exactly the same distance apart over their full length perpendicular At right angles precision, precise relative represents resolution rotated variation Exact (also see accurate ) Comparing two or more things e.g. Measurements Shows, is equal to, is the same as The smallest unit that the instrument can measure Turned A change 72