Ch 4 Measurements - kau 4 Measurements.pdfA measuring tool for taking inside and outside...

Dr. Abdel-Wahab El-Morsy Faculty of Engineering - Rabigh

Basic WorkshopBasic Workshop

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Measuring Instruments

Measuring Instruments


Indirect measuring devices

Caliper Radius GaugePlug Gauge

Direct measuring devices

Vernier Caliper Micrometer Vernier Bevel Protractor

Vernier Caliperا�-,+) ذات ا��ر(�)

A measuring tool for taking inside and outside measurements

Measuring Range

Direct Measuring Devices


Measuring Range

0 – 100, 0 – 125, 0 – 150, 0 – 200, …..

Sensitivity

0.1, 0.05, 0.02 mm



1) Outside jaws: used to measure external length

2) Inside jaws: used to measure internal length

3) Depth probe: used to measure depth

4) Main scale (cm)

5) Main scale (inch)

6) Vernier (cm)

7) Vernier (inch)

8) Retainer: used to block/release movable part

Reading the Vernier Scale



Vernier Depth gauge

Vernier inside gauge



Vernier outside gauge

Vernier long outside gauge

• Range 0 – 100, 0 – 125, 0 - 200mm

• Sensitivity 0.1, 0.05, 0.02 mm

Vernier Height gauge



• Range 0 – 300, 0 – 500 mm

• Sensitivity 0.1, 0.05, 0.02 mm

34 0.60 34.6 mm+ =

Examples



34 0.60 34.6 mm+ =

37 0.46 37.46 mm+ =

GH+وGJ�Kا�Micrometer

A tool for taking outside, inside, and height measurements.

Measuring Range



0 – 25, 25 – 50, 50 – 75, ……..

Sensitivity

0.01 mm

The rim of the thimble is divided into 50 parts, which gives a reading of

0.01 mm. the barrel is marked in millimetres and ½ mm divisions, so

that when we take a reading we add the number of hundredth indicated

on the thimble to the millimetres and ½ mm uncovered on the barrel.


Reading the Micrometer


A = 7.00 mm

B = 0 mm

C = 38 x 0.01 = 0.38 mm

Reading the Micrometer



C = 38 x 0.01 = 0.38 mm

A + B + C = 7.0 + 0 + 0.38

= 7.38 mm

A = 7.00 mm

B = 0.5 mm

C = 22 x 0.01 = 0.22 mm

A + B + C = 7.00 + 0.50 + 0.22

= 7.72 mm


Types of Micrometers


Measure test pieces with an uneven number

Micrometers with prismatic measuring faces




For measuring grooves, feather grooves, splines

and other difficult to reach measuring points

Measure test pieces with an uneven number

of grooves such as milling cutters, taps, and

drills as well as odd polygons

Micrometers with Small Measuring Faces

Rounded measuring faces for

measuring concave surfaces

Micrometers with two spherical measuring faces




measuring concave surfaces

Micrometers for gear pitch measurement

Flanges with ring-shaped measuring faces

for root tangent lengths on gear pitches,

distance between grooves and slots.

Micrometers for Thread Measurement




Used for pitch diameter inspection-Anvil

with adjustable holder for mounting a

measuring insert with prismatic faces .

Depth Micrometers

With interchangeable measuring rods provided in

sets. The rods are adjusted in steps, each with a step

length of 30 or 25 mm.

Exercises



Angles Measurements

� A tool used to measure angles.

� The sliding blade is connected to a Vernier scale,

� The main scale is divided up into degrees from 0 to 90 each way.

� Range 4 × 0 - 90.

� Sensitivity = 5 minDegree (°) = 60 min (′60)

Minute (`) = 60 second (′′60)



� Sensitivity = 5 minMinute (`) = 60 second (′′60)

Degree (°) = 3600 second (′′60)

(P�QRا� (S-TKا�Plate Protractor


Angles Measurements


(+�Uا� (Vر�WKا� (S-TKا� Combination Squares

Vernier Bevel Protractor ا�S-TK) ذات ا��ر(�)

A tool used to measure angles. The sliding blade is connected to a Vernier

scale, the main scale is divided up into degrees from 0 to 90 each way.

Range 4× 0 -90.


Angles Measurements


Range 4× 0 -90.

Sensitivity 5 (minutes)

= 1/12° × 60

= 5 minutes



Angles Measurements


Reading the Bevel Protractor


Angles Measurements


Exercise



Angles Measurements


Exercise



Exercise

Angles Measurements


Exercise

Try Square

Care should be taken to ensure that its blade

is perpendicular to the surface being tested.

Indirect Measuring Devices


Try Square



Inside and outside caliper

A tool used in measuring inside and outside diameters. When the tool has

been adjusted, the diameter may be read from a rule or Vernier caliper.



Plug thread gauge



Radius gauge

A tool used for testing the accuracy of holes. Plug gauges are usually made

double-ended for checking two dimensions.

A tool used for testing concave and convex corners.

Telescoping Gauges



• Used to measure inside cylinders.

• Allow “T” gauge to extend to inside opening

• Lock shaft

• Measure with micrometer

A tool used for testing the space between two surfaces


Wire GaugeFeeler Gauge


36

Dial Indicators

The dial indicators or dial gauges are generally used for testing flatness of surfaces

and parallelism of bars and rods. They are also used for testing the machine tools.



Measuring Devices37


The primary aim of modem manufacturing is to produce

product of high quality. In producing high quality products,

Specifications and Standardization


product of high quality. In producing high quality products,

all components must be manufactured in accordance with

the specifications

Specifications

Specifications used in manufacturing include:

� Size,� Location,� Surface finish,



� Surface finish,� Material.. etc.

If the product is used as a component in other products or by various manufacturers, the

specifications become a standard for that particular item.

For example, a bolt can be manufactured having any number of threads, diameters and

pitches. If a bolt’s specifications meet their particular needs, other manufacturers may

want to produce it. In order for the bolt to be interchangeable with a nut, the thread sizes

must be compatible. Hence, this particular thread specification becomes standardized

throughout the industry

Standardization

Standardization is the act of conforming to standard, which is established by authority as"

a fixed rule or measure. Standards are established in the fields of products, materials,

processes, equipment and procedures by National and International Organization such as:



� International Standards Organization (ISO).� British Standards Organization (BSO).� German Industria1 Standard (DIN).� American National Standards Institute (ANSI).

In modem industry it is essential to follow some code of standards in order to ensure the

ability to interchange products between different manufacturers on the one hand, and

between different countries on the other

An engineering drawing of a manufactured part is intended to convey information

from the manufacturer and inspector. It must contain all information necessary for

the part to be correctly manufactured.

It must enable the inspector to make a precise determination of whether or not the

Dimensions and Tolerances


It must enable the inspector to make a precise determination of whether or not the

parts are acceptable. Drawings must convey three essential types of information:

• The materials to be used.

• The dimensions of the part.

• The shape of the part

It is difficult to produce any part to an exact dimension. For example it is very

difficult to produce bars having a length of exactly 80 mm. Small variations in

length must take place even on the most accurate machines. Thus we specify

tolerances on the dimension of the part, say 80±0.1mm. Thus all bars longer

than 79.99 mm and shorter than 80.01mm are acceptable



Tolerance The tolerance on a dimension is the total

permissible variation in its size, which is

equal to the difference between the limits

of size

than 79.99 mm and shorter than 80.01mm are acceptable

40±±±±0.2

20.019.4

+0.1- 0

10 2 Holes Tolerance 0.6

Tolerance 0.4

Tolerance 0.1

Limits of Size

The limits of size, often referred to as the limits, are the maximum and minimum

permissible sizes for a specific dimension

Limits of size



40±±±±0.2

20.019.4

Limits of sizeHigh limit placed above low limit

Limits are 40.2 and 39.8

Allowance

An allowance is a prescribed difference between the maximum size of an external feature

and the minimum size of a mating internal feature. It is therefore the minimum clearance

or the maximum interference which exists between such features when they are assembled



Ch 4 Measurements - kau 4 Measurements.pdfA measuring tool for taking inside and outside...

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