ME 472 – Engineering Metrology and Quality Control

Chp 5 - Linear and Angular Measurements

D A T l B dMechanical Engineering Dr. A. Tolga BozdanaAssistant Professor

Mechanical EngineeringUniversity of Gaziantep

Measuring tools and instruments

Measuring tools and instruments

Direct (contact) measurement(e g micrometer or caliper)

Indirect (non-contact) measurement(such as optical electronic and(e.g. micrometer or caliper) (such as optical, electronic and

pneumatic methods)

Non-graduated(gauges or adjustable tools which compare

Graduated(either linear or angular

graduations incorporated intoNEXT WEEK!

tools which compare the measurements)

graduations incorporated into measuring system of the tool)

Rules Calipers Rules Vernier Calipers Vernier Ga(u)ges Micrometers

p Gauges and Ga(u)ge Blocks Sine Bar Special-purpose tools

1

Protractors Dial Indicators

Graduated Linear Measurement - Rules

Imperial steel rulesImperial steel rules(with graduations on each side)

Metric steel rules(with graduations on each side)

resolution?

(with graduations on each side)

How to read a rule: A = 22 mm (22nd graduation)

resolution?

A 22 mm (22 graduation)

B = 12 mm (12th graduation)

C = 31 5 mm (between 31st and 32nd)

2

C 31.5 mm (between 31st and 32 d)

D = 40.5 mm (between 40th and 41st)

Graduated Linear Measurement - Vernier Calipers

More precise tools capable of measuring externaland internal dimensions as well as depths.

How to read a vernier caliper:

First, read the graduation on main scale justb f i l t t (i 19th d tibefore vernier scale starts (i.e. 19th graduationwhich gives 19 mm)

Next, read the graduation on vernier scale, gwhere two graduation lines on main & vernierscales perfectly match (i.e. 32nd graduationwhich gives 32 * 1/50 = 0.64 mm)

3

Finally, add fine reading into main reading(i.e. 19 + 0.64 = 19.64 mm)

Graduated Linear Measurement - Vernier Calipers

Direct reading of an internal length by digital vernier caliper Di t di f t l l thby d g ta e e ca pe Direct reading of an external length

by digital vernier caliper

Vernier caliper with a dial indicator

4

Graduated Linear Measurement - Vernier Height GaugesDesigned for use in toolrooms, workshops, inspection departments in order to measureand/or mark off vertical and locating center distances.

5Dial Height GaugeStandard Height gauge Digital Height Gauge

Graduated Linear Measurement - Vernier Depth GaugesDesigned for use in toolrooms, workshops, inspection departments in order to measure depths of holes, slots, recesses, and so on.

6Standard Depth Gauge Digital Depth GaugeDial Depth Gauge

Graduated Linear Measurement - Outside Micrometers

VERNIER READING THIMBLE READING

Metric MicrometerMetric Micrometer

SLEEVE (BARREL) READING

H t d i t i i tB

Vernier Metric Micrometer

How to read a vernier metric micrometer:Sleeve div. = 1 mmThimble div. = 1/50th of sleeve sub-div. = 1/100 mm

B

Vernier

Vernier div. = 1/10th of thimble div. = 1/1000 mm

A. The highest figure: 5 * (sleeve div.) = 5 mmD

Thimble Division

Division

A. The highest figure: 5 (sleeve div.) 5 mmB. The half-figures: 1 * (sleeve sub-div.) = 0.5 mmC. The highest figure: 28 * (thimble div.) = 0.28 mm

C

7

D. The matching figure: 3 * (vernier div.) = 0.003 mmFINAL READING = A + B + C + D = 5.783 mmASleeve

Division

Graduated Linear Measurement - Outside Micrometers

Dial-indicating MicrometersV-anvil Micrometers (measuring odd-fluted taps, milling cutters, reamers as well as checking out of roundness)

Screw Thread Micrometer (measuring pitch diameter

of screw threads)

Direct-reading Micrometer

8

of screw threads)

Graduated Linear Measurement - Inside Micrometers

Standard Inside Micrometers Digital Inside Micrometersg

9

Graduated Linear Measurement - Micrometer Bore and Depth Gauges

Micrometer Hole and Bore Gauges

Inside Micrometer Set

Micrometer Depth Gaugesp g

10

Graduated Angular Measurement - Protractors

(b)

(a)

( )Simple

Protractor(measuring angles from

Measuring acute (a) and obtuse (b) angles

angles from 0 to 180º) Universal Bevel Protractor (main scale

consists of 4 portions of 90º)

How to read an angle on a bevel protractor:Main div. = 1º = 60′Vernier div. = 1/12th of main div. 0.0833º = 5′

The highest figure: 50 * (main div.) = 50º

11

The matching figure: 4 * (vernier div.) 0.333º = 20′ The final reading is: 50.333º or 50º 20′

Special Purpose Measurement Tools

Level (used for setting up and testing machinery)

Dial test indicator mounted on ti t d ( da magnetic stand (used as an

apparatus with machine tools for specific measurements)

12

Combination set (a square, a level, a depth/height gauge, and a bevel protractor with centring head)

Non-Graduated Linear Measurement - Calipers Standard calipers have a fine adjustment screw and a quick-adjusting spring nut.

Accuracy obtained with these tools depends mostly on the inherent skill of users.

The measurements are carefully transferred to a graduated measuring tool.

Caliper for internal Caliper for external Caliper used

13

Caliper for internal measurements

Caliper for external measurements

Caliper used as a divider

Non-Graduated Linear Measurement - Gauges

Telescopic Gauges(consist of a handle with(consist of a handle with two plunger-contacts at right angles to a handle

which both lock simultaneously)

Small Hole Gauges (consist ofSmall Hole Gauges (consist of an expanding ball head adjusted to size by a knurled knob to provide an accurate “feel” for obtaining Surface Gauge (consists of a groundmeasurements in a hole or slot)

Surface Gauge (consists of a ground rectangular base with a round upright rod and a fine adjustment feature on the base. It can be used in a layout work for scribing

14

y glines on vertical/horizontal surfaces as well

as in inspection work as height/depth gauge)

Non-Graduated Linear Measurement - Special Purpose Gauges

S Pit h G ( i t f t l iScrew Pitch Gauges (consist of a metal case preserving many separate leaves. Each leaf has teeth corresponding to a definite pitch. By matching the teeth with the thread on work, the correct pitch can

be read directly from the leaf)be read directly from the leaf)

Tap and Drill Gauges (consist of a flat rectangular steel plate with

15

g pholes accurately drilled and

identified according to their size) Radius Gauges (available as individual leaves and each leaf is marked with its radius. Designed to check convex/concave radii)

Non-Graduated Linear Measurement - Rectangular Gauge Blocks

(a) (b) (c)

Linear Gauge Blocks: (a) rectangular, (b) square, (c) square with center hole

16

Non-Graduated Angular Measurement - Angle Gauge Blocks

parallel+3º+5º+5

+30ºTarget: 38º

Complete set of angle gauge blocks

17

Setting a revolving magnetic chuck using angle gauge blocksTrue Square

Non-Graduated Angular Measurement - Sine Bar

How to use Sine Bar:

We want to set an angle of 14º 12′using a 10 mm sine bar.

Thi l 10 d θ 14 2º This means: l = 10 mm and θ = 14.2º

So: h = l * sin θ = 2.453 mm

Therefore the combination of blocks Therefore, the combination of blocks providing this height must be used.

Limitations of Sine Bar: When using a sine bar, the height setting is limited by the available gauge block divisions. This results in an error that may be negligible or in some cases quite significant.

18

y g g q g Due to the nature trigonometry; at larger angles, it is susceptible to errors in the length of the sine bar as well as in the height of the gauge blocks.