Linear MeasurementLinear Measurement

It is applied to measurement of It is applied to measurement of length, Diameter, Height, and length, Diameter, Height, and thickness including external and thickness including external and internal measurement.internal measurement.

The line measuring instrument have The line measuring instrument have series of accurately spaced lines series of accurately spaced lines marked on them.marked on them.

e.g : Scale e.g : Scale

Linear measurements can be Linear measurements can be classified asclassified as

1.1. Direct measuring instrumentDirect measuring instrument

2.2. Indirect measuring instrumentIndirect measuring instrument Direct measuring instrument have Direct measuring instrument have

two typestwo types

1.1. Graduate 2. Non GraduateGraduate 2. Non Graduate

In graduate instrument include rules, In graduate instrument include rules, vernier callipers, vernier hight gauge, vernier callipers, vernier hight gauge, vernies Depth gauge, Micrometer, vernies Depth gauge, Micrometer, Dial indicator.Dial indicator.

Non graduate instrument include Non graduate instrument include wire gauge, Screw pitch gauge, wire gauge, Screw pitch gauge, radius gauge, thickness gauge, slip radius gauge, thickness gauge, slip gauge etc.gauge etc.

They can be classified asThey can be classified as

1.1. Non precision instrument such as Non precision instrument such as steel rulesteel rule

2.2. Precision measuring instrument Precision measuring instrument such as vernier, micrometer etc.such as vernier, micrometer etc.

Steel rule:Steel rule:– It is a line measuring device.It is a line measuring device.– It is a part replica of the international It is a part replica of the international

prototype meter.prototype meter.– Its made from stainless steel having Its made from stainless steel having

series of equally spaced lines engraved series of equally spaced lines engraved on it.on it.

– It is most common used in workshopIt is most common used in workshop– It manufacture in different sizeIt manufacture in different size

Precaution while using steel rulePrecaution while using steel rule

1.1. The rule should never be used for The rule should never be used for cleaning between parts or substitute cleaning between parts or substitute for screw driver.for screw driver.

2.2. To maintain sharpness of the To maintain sharpness of the graduation for easy and accurate graduation for easy and accurate reading.reading.

3.3. To avoid parallax error while making To avoid parallax error while making measurement eye should be at 90measurement eye should be at 9000

4. When taking measurement with rule 4. When taking measurement with rule it required graduation marks are as it required graduation marks are as close as possible to the face being close as possible to the face being measured.measured.

CallipersCallipers

The steel rule alone is not a The steel rule alone is not a convenient method of measuring convenient method of measuring directly the size of the circular part.directly the size of the circular part.

A calliper is usde to transfer the A calliper is usde to transfer the distance b/w the faces of distance b/w the faces of component to a scalecomponent to a scale

Classification of callipersClassification of callipers

1.1. Outside callipersOutside callipers

2.2. Inside callipersInside callipers

3.3. Transfer callipersTransfer callipers

4.4. Odd edge callipersOdd edge callipers

Outside calliper:Outside calliper:

Inside callipers:Inside callipers:

Odd leg calippersOdd leg calippers

Angle plate:Angle plate:

V-blockV-block

Universal surface gaugeUniversal surface gauge

VERNIER CALLIPERVERNIER CALLIPER

Vernier calliper readingVernier calliper reading = main = main sacle reading + The number of sacle reading + The number of division which exactly coincide with a division which exactly coincide with a number of main division x Least number of main division x Least countcount

Least count vernier instrument:Least count vernier instrument: vernier instrument have two scale vernier instrument have two scale

main scale and vernier scale.main scale and vernier scale. Main scale is fixed and vernier scale is Main scale is fixed and vernier scale is

slides on the main scale.slides on the main scale. When the zero of main scale coincides When the zero of main scale coincides

with zero of vernier scale the vernier with zero of vernier scale the vernier scale has one more division than the scale has one more division than the main sacle main sacle

Least count = value of smallest Least count = value of smallest division on main scale/ number of division on main scale/ number of division on the vernier sacle.division on the vernier sacle.

L.C = 1/50L.C = 1/50

= 0.02 mm= 0.02 mm

Vernier height gaugeVernier height gauge

A Vernier height A Vernier height gauge has finely gauge has finely grounf base.grounf base.

Base is massive Base is massive and robust in and robust in construction to construction to ensure rigidity and ensure rigidity and stability.stability.

Masssive base give Masssive base give support to the support to the graduated beamgraduated beam

The vernier height The vernier height gauge is design for gauge is design for the accurate the accurate measurement and measurement and marking of vertical marking of vertical height above the height above the surface plate.surface plate.

It can also be used It can also be used to measure the to measure the differences b/w two differences b/w two height.height.

It can be used for number of It can be used for number of application in tte tool room and application in tte tool room and inspection department.inspection department.

Important FeaturesImportant Features

All the parts made of good quality All the parts made of good quality steel.steel.

Beam has sufficient rigidity.Beam has sufficient rigidity. Measuring jaw should be flat.Measuring jaw should be flat. Slider should have good sliding.Slider should have good sliding. Height gauge can also be provided Height gauge can also be provided

with dial gauge to get exactly and with dial gauge to get exactly and easy reading.easy reading.

Vernier Depth gaugeVernier Depth gauge

VERNIER DEPTH GAUGEVERNIER DEPTH GAUGE Vernier depth gauge is Vernier depth gauge is

used to measure the used to measure the depth of holes, slots.depth of holes, slots.

It consist a sliding head It consist a sliding head it having flat and true it having flat and true base.base.

A graduate beam known A graduate beam known as main scale and and as main scale and and sliding head slide over sliding head slide over the graduate beam.the graduate beam.

Beam is perpendicular Beam is perpendicular to the base and its flat to the base and its flat from the both ends.from the both ends.

While using this While using this instrument the base is instrument the base is held over the reference held over the reference surface and lower beam surface and lower beam go downward until it go downward until it contact the bottom contact the bottom surface of the hole.surface of the hole.

The clamping screw then The clamping screw then tightened and remove tightened and remove vernier from the work vernier from the work piece and take reading piece and take reading same way of the vernier same way of the vernier caliper. caliper.

Combination Square (Combination Combination Square (Combination set)set)

it consist of it consist of

1.1. Steel ruleSteel rule

2.2. Square headSquare head

3.3. Centre headCentre head

4.4. Protector headProtector head

It is use in layout and It is use in layout and inspection workinspection work

Steel rule grooved Steel rule grooved along its length and along its length and sliding square fitted sliding square fitted in this groove.in this groove.

On surface of the On surface of the square head is square head is always perpendicular always perpendicular to the rule.to the rule.

And it can be adjust at And it can be adjust at any point by the any point by the clamping screw.clamping screw.

Center square is Center square is obtain for finding the obtain for finding the center line of center line of cylindrical object.cylindrical object.

The centre square The centre square slotted at centre so slotted at centre so that the rule when that the rule when inserted bisect the 90inserted bisect the 9000 angle.angle.

MicrometerMicrometer

Micrometer works on principle of Screw and Micrometer works on principle of Screw and nut.nut.

When the screw is turn through the nut When the screw is turn through the nut through one revolution it advance by one through one revolution it advance by one pitch distance.pitch distance.

Least count of micrometerLeast count of micrometer The Micrometer has a screw of 0.5 mm The Micrometer has a screw of 0.5 mm

pitch with a thimble graduated in 50 pitch with a thimble graduated in 50 division to provide a direct reading of division to provide a direct reading of

Pitch/n = 0.5/50 = 0.01 mmPitch/n = 0.5/50 = 0.01 mm

Micrometer total reading = Micrometer total reading =

Main scale reading + Reading on the Main scale reading + Reading on the thimble * L.Cthimble * L.C

Depth MicrometerDepth Micrometer

Telescopic gaugeTelescopic gauge It is used for measure the It is used for measure the

internal diameter of internal diameter of holes, slots , grooves etc.holes, slots , grooves etc.

It consist of a handle with It consist of a handle with two rods in a tube at one two rods in a tube at one end and a working screw end and a working screw at other end.at other end.

The rods having spherical The rods having spherical contacts can slide within contacts can slide within a tube and a force apart a tube and a force apart by internal spring.by internal spring.

The locking screw can lock the rods at The locking screw can lock the rods at any desire position through the spring.any desire position through the spring.

While taking the measurement the rods While taking the measurement the rods

are pressed closer and inserted the hole are pressed closer and inserted the hole to be measured.to be measured.

The rods then open out to touch the The rods then open out to touch the metal surface of the hole on both side.metal surface of the hole on both side.

Then its lock by means of locking screwThen its lock by means of locking screw

Then it taken out from the hole.Then it taken out from the hole. And the dimension across tips And the dimension across tips

measured by micrometer.measured by micrometer.

Slip gaugesSlip gauges

Slip gauges are rectangular blocks of Slip gauges are rectangular blocks of high grade steel with close tolerance.high grade steel with close tolerance.

It ensure the resistance to wear.It ensure the resistance to wear. They are than stabilized by heating They are than stabilized by heating

and cooling successively in stages so and cooling successively in stages so that hardening stresses are removed.that hardening stresses are removed.

After being hardened they are carefullyAfter being hardened they are carefully

Finished by high grade lapping.Finished by high grade lapping.

to a high degree finish, flatness and to a high degree finish, flatness and accuracy.accuracy.

Its having a truly flat surface for Its having a truly flat surface for accurate reading.accurate reading.

The cross section of these gauge is 9 The cross section of these gauge is 9 x 30 mm for size upto 10 mmx 30 mm for size upto 10 mm

And 9 x 35 mm for larger size.And 9 x 35 mm for larger size.

Slip gauges are used forSlip gauges are used for To get the high accuracyTo get the high accuracy For checking the accuracy of vernier For checking the accuracy of vernier

calliper, micrometer and such other calliper, micrometer and such other measuring instrument.measuring instrument.

For measure the angle of work piece.For measure the angle of work piece.

Wringing of slip gaugeWringing of slip gauge