•Ruler and Transfer Calipers

–A ruler measures in fractions of an inch

–Common metric rulers measure in centimeters

–A tread depth gauge is a type of ruler.

•It is a common tool used to determine the amount of wear on a tire.

•Micrometers and Feeler Gauges

–Many automotive parts require precision measurement

–Typically, these tools are accurate to 0.001”

–A micrometer would be used to measure valve stem outer diameter.

•Dial Indicators

–Used to measure precision variation

–Reading is difference between highest and lowest dial points.

–Typically accurate to .001”

–Rotor run-out is an example of a measurement taken with a dial indicator.

•Angles and Protractors

–Technicians measure angles during several inspection procedures

–A vehicle alignment measures and adjusts many angles

–Driveline working angle is an example of a simple angular measurement

•Vernier and Dial Calipers

–Calipers are typically used for quick measurement

–Typically not as accurate as a micrometer

–Can be used for inside, outside, or depth measurement

•Meters and Gauges

–Units will be labeled on gauge face

–Commonly used for pressure and flow measurements

–Follow service instruction carefully for most accurate measurement

•Electricity

–Voltage, amperage, and resistance are most common measurements

–Extra caution and PPE should be used with high amperage/voltage measurements

–Conversions are frequently necessary when comparing specs to measurements

•Hydraulics

–Pascal’s Law allows technicians to use known pressures and ratios to calculate expected hydraulic pressure

–Modern braking systems are an everyday application of Pascal’s law

–Most new electronic brake units have at least one hydraulic pressure sensor

•Ratios

–Essential to determining: gearing, movement in hydraulic system, or air/fuel mixture

–Ratios are the basis for conversions (i.e. fixed ratio between units)

–Require multiplication and division

•Conversions

–Conversions factors are ratios (i.e. fixed ratio between units)

–Essential when specified units do not match measuring equipment.

–Frequently used to determine proper fluid fill