1 Introduction To Scales Introduction 2 Earlier We talked about Dimensions T Parts of the dimension object OExtension lines ODimension line OArrowheads ONumeric value T ocation of the numeric value Earlier 3
Scales Objectives You should understand Types of scales T You will be able to identify the difference between the different scales Use of scales T Using a scale, you will be able to measure objects shown on civil engineering plans and architectural renditions of buildings and structures How to read a scale T You will be able to interpret the results of the measurements Objectives 4 Types of Scales These are not rulers There are five types of scales Decimal Mechanical Metric T 1:50 scale Engineers T A 10 scale means that every 1" on a drawing equals 10' in reality T Or 20 scale means one inch equals 20 Architectural T 1/4" = 1'-0" OEvery 1/4 on a drawing equals 1 foot of actual length on the project. O1/8" = 1'-0" or 1 ½" = 1'-0" Types of Scales 5 Types of Scales There are two types of drafting scales used in design and construction: Engineer, or civil, scales T 1 = 10 or 1 = 50, are used for measuring roads, water mains, and topographical features Architect scales T 1/4 = 1-0 (1/48 size) or 1/8 = 1-0 (1/96 size), are used for structures and buildings Types of Scales 6
Using a Scale It is not always practical to create full-size drawings of objects Drawings are reduced to a manageable size (scale) so they can be studied The word scale is used synonymously to represent the tool and the size reduction in the drawing Using a Scale 7 Architect scales Have numbers that run incrementally both from left to right and from right to left A whole number or fraction to the left or right of the number line indicates the scale those numbers represent. Architect scales 8 Architect s Scale 3/32 = 1 foot 1/8 = 1 foot 3/16 = 1 foot 1/4 = 1 foot 3/8 = 1 foot 1/2 = 1 foot 3/4 = 1 foot 1 inch = 1 foot 1½ inches = 1 foot 3 inches = 1 foot Architect s Scale 9
Smallest Tick Marks Scale 3/32" 3/16" 1/8" 1/4" 3/8" 3/4" 1/2" 1" 1 ½" 3" Smallest tick mark 2" 1" 2" 1" 1" 1/2" 1/2" 1/4" 1/4" 1/8 " Smallest Tick Marks 10 11 Quiz Time 1' -6" Quiz Time 12
Quiz Time 7' -4" Quiz Time 13 Quiz Time 8 inches Quiz Time 14 Quiz Time 2" Quiz Time 15
Quiz Time 3'-8" Quiz Time 16 Engineer s Scale 1" = 10' (may also be 100', 1000' or even 10,000' 1" = 20' 1" = 30' 1" = 40' 1" = 50' 1" = 60' Engineer s Scale 17 Engineer scales Have numbers that run incrementally from left to right The whole number to the left of the number line indicates the scale those numbers represent Engineer scales 18
Reading Engineer s Scale Reading 19 How to Scale a ine with an Engineer s Scale 164' 16 + 4 How to Scale a ine with an 20 Using a Fractional Rule to Scale Using a Fractional Rule to Scale 21
What is the Dimension 15'-9" What is the 22 What is this Dimension 2'-11 ¼" What is this 23 What is the Dimension 4'- 4" What is the 24
Summary Types of scales T You should be able to identify the difference between the different scales, especially Engineering/Architectural Use of scales T You should be able to measure objects shown on an architectural renditions of buildings and structures How to read a scale T You should be able to interpret the results of the measurements Summary 25 Measurements and Precision Measuring Devices Measurements and Precision Measuring 26 Objectives Describe United States Customary (USC) system of measurement Describe metric system Explain how to convert measurements between two measuring systems Explain when and how to read rulers Discuss need for feeler gauges and their general use Describe how to read measurements made with micrometers Describe dial indicators and calipers Explain typical uses of vacuum and pressure gauges Objectives 27
Introduction Methods of collecting data depend on what is being measured Check for excessive wear or damage when servicing components Some shops send components out for these measurements and tests Introduction 28 Measuring Systems Most common measurement in the U.S. is the United States Customary (USC) Based on the inch Can be measured in decimals or fractions Engine measurements are expressed in thousandths of an inch Measuring Systems 29 English System? The English system of measurement grew out of the creative way that people measured for themselves. Familiar objects and parts of the body were used as measuring devices. T For example, people measured shorter distances on the ground with their feet. They measured longer distances by their paces (a "mile" was a thousand paces). They measured capacities with common household items such as cups, pails, and baskets. The word gallon comes from an old name for a pail. OMiddle English galon, a liquid measure, from Anglo-French galun, jalun, ultimately from Medieval atin galeta pail, a liquid measure English System? 30
English system In the English system, the fundamental units of force, length, and time are expressed in the standard units of foot, pound, and second. Unlike the metric system, the English system has no common multiplier and the subdivisions of the units of measurement bear no common relation to each other. English system 31 Units of ength 12 inches = 1 foot 3 feet =1 yard 5 1/2 yards = 1 rod (16 1/2 feet) Units of Weight 16 ounces = 1 pound 2000 pounds = 1 ton (short) 2240 pounds = 1 ton (long) 32 INEAR EQUIVAENCE Conversion Factors English to Metric 1 inch = 1 foot = 5,280 feet = 1 mile = 2.54 centimeters (= 0.254m) 0.3048 meters (= 304.8mm) 1.34 kilometers Metric to English 1 centimeter = 1 meter = 1 kilometer = 0.3937 inches 3.280 feet (= 39.37 inches) 0.746 miles (= 3,280.84 feet) 33
Measuring Systems Metric system based on the meter OOriginally, a meter would be defined as one 10-millionth of the distance from the North Pole to the equator Oin 1960, the meter was define based upon a wavelength of krypton-86 radiation OThe meter is defined to be the distance light travels in 1 / 299,792,458 seconds. T Most common units in the industry are the centimeter and millimeter T Millimeters are used to express close tolerances of measurements T Metric system is based on divisions of ten Measuring Systems 34 Metric System Such units as length, volume(capacity), and mass are easily converted to the next higher denomination by using the simple multiplier, 10 Metric System 35 Metric System Units of ength 10 millimeters = 1 centimeter 10 centimeters = 1 decimeter 10 decimeters = 1 meter 1000 meters = 1 kilometer Units of Weight 10 milligrams = 1 centigram 10 centigrams = 1 decigram 10 decigrams = 1 gram 1000 grams = 1 kilogram 1000 kilograms = 1 metric ton Metric System 36
Rulers and Feeler Gauges Rulers Simple tools to measure straight-line distances where tolerances are not a major factor May be USC or metric Can be made of metal, plastic, or wood Typical rulers are 6 inches or 12 inches Rulers and Feeler Gauges 37 Rulers and Tapes Rulers and tapes. The most common method of obtaining simple measurements of length is by the ruler or tape. T A ruler may be graduated into feet, inches, or fractions thereof. T Rulers and tapes used in engineering work are most frequently made of metal and the fractions of inches may be graduated to subdivisions as small as 1/64 or 1/100 of an inch. OCare should be exercised in using metal rulers and tapes, especially if extreme accuracy is required. OThe margin of error due to expansion or contraction of the instrument from changes in temperature can be considerable. Rulers and Tapes 38 39
40 Calipers Calipers Engineers and machinists frequently use calipers to secure accurate measurements of inside and outside diameters. Calipers 41 42
Feeler Gauges Feeler Gauges Precision-machined piece of metal that is flat or round May be USC or metric Used for measuring gaps or the space between two objects Proper usage requires practice Feeler Gauges 43 44 Feeler Gauges used for Valve lash Measure spark plug gap Head flatness Thrust distance in Crankshaft Ignition point gap (Old Vehicles) Feeler Gauges used for 45
Feeler Gauges Feeler gages are principally used in determining clearances between various parts of machinery. Probably the most common use is determining valve clearance The thickness of the blade then determines the clearance Feeler Gauges 46 47 Micrometer ID 48
49 Micrometers Micrometer calipers. Engineers frequently rely on the micrometer caliper to obtain measurements accurate to 1/1000 of an inch. T This instrument is particularly useful for measuring relatively short lengths and the diameter of journals or cylinders. T The common commercial micrometer consists of a frame; an anvil, or fixed measuring point; a spindle; a sleeve, or barrel; and a thimble. OThe spindle has threads cut 40 to the inch on the portion that fits inside the sleeve. OThe thimble fits over the end of the sleeve, and rotating the thimble turns the spindle. Micrometers 50 Micrometers Micrometers precisely measure different shapes of a component Outside micrometers Resembles a clamp to measure linear distances Proper use requires practice and studying the markings of the instrument Micrometers 51
Reading a Micrometer Sleeve: The Micrometer sleeve is divided into 10 equal parts, each of these parts is equal to.100" (1 tenth of an inch). Each of these 10 parts is divided into 4 equal parts. Each of these 4 subdivisions is equal to.025" or one 40th of an inch. OMore simply, the line on the sleeve marked "1" represents.100", the line marked "2" represents.200" and so forth. Reading a Micrometer 52 Reading a Micrometer The Sleeve does not move. It looks like a ruler with ten numbers. The space between each number is divided into quarters. As the Thimble rotates around this Sleeve it covers up, or reveals the numbers marked on the Sleeve. Reading a Micrometer 53 Thimble The thimble is divided into twenty-five equal parts, each of these parts is equal to.001" and, one complete rotation of the thimble coincides with the smallest division (.025") on the sleeve. Thimble 54
Micrometers Reading a USC Outside Micrometer Place anvil against work Rotate thimble to bring spindle into contact with opposite side of work Use ratchet knob to ensure sufficient contact is made Remove micrometer and read dial Micrometers 55 Telescopic Gauges Used with outside micrometers to measure inside diameters Various lengths and T-shaped Extensions are spring-loaded Telescopic Gauges 56 Telescoping Gauges Telescopic Gauges eg has a rotatable handle to lock extensions in place Once gauge is removed, measure with outside micrometer Telescoping Gauges 57
Parts of a Telescoping Gauge 58 Inside Micrometers 59 Depth Micrometers 60
Small Hole Gauges To measure small holes Gauge is straight with a screw handle on one end and a split ball on other Handle is turned to expand ball T Removed and measured with a micrometer Small Hole Gauges 61 Dial Indicators Dial Calipers For inside, outside, and depth measurements Manual scales or digital USC can measure in 0.001 inch increments Metric can measure in 2-millimeter increments Dial Indicators 62 Dial Indicators Dial Indicators To check how far components can move Scale can be USC or metric Face can be balanced or continuous To check runout or end play Dial Indicators 63
64 Pressure and Vacuum Measurements Pressure Gauges Measure amount of pressure applied to a closed, sealed system Fitted into pressure line with appropriate fittings Vacuum Gauges Mechanical gauge measures difference between atmospheric pressure and current state of system Pressure and Vacuum Measurements 65 Summary Most common measurement system in United States is the United States Customary or the English system Base USC measurement is the inch Base metric measurement is the meter Use proper measuring tool for the job Summary 66