CLEANING & DEBURRING EQUIPMENT GAUGE Johannsen gauges Cross-section:30 mm×09 mm Classification As per accuracy Master slip gauge AA: ±2µ/m Reference slip gauge A: ±4µ/m Working

LINEAR MEASUREMENT

Prof.H M Prajapati & Prof. A R Sankhla

Introduction

Classification

Based on the type of standard

Line measurement

End measurement

Based on precision

Precise

Direct: Vernier caliper, Micrometer

Indirect: Telescopic gauge, bore gauge

Non-precise

Direct: Steel rule

Indirect: Caliper


Engineer’s Steel rule

Material:

L. C. =

Length = 150, 300, 600, 1000 mm

Types: Shrink rule, folded form

Parallax

Hardened steel

0.5 or 1 mm


CALIPERS

Material

Leg: Carbon steel or alloy steel

Hardness: 650 ±50 HV

Spring: Carbon spring steel

Classification

Spring and Firm joint caliper

Outside, Inside, Transfer, Hermophrodite

Nominal size

Firm joint caliper: 100, 150, 200, 300 mm

Spring caliper: 75, 100, 150, 200, 250, 300 mm


Outside CALIPERS

How to get numeric value?Prof.H M Prajapati & Prof. A R Sankhla

Inside CALIPERS

How to get numeric value?Prof.H M Prajapati & Prof. A R Sankhla

CALIPERS

Inside caliper

(Firm joint & Spring)

Outside caliper

(Firm joint & Spring)


Transfer CALIPERS


Hermophrodite CALIPER


Divider


Vernier caliper

When two scales or divisions slightly different in sizeare used, then difference between them can beutilized to enhance the accuracy of measurement.


Vernier Caliper

Parts of vernier caliperProf.H M Prajapati & Prof. A R Sankhla

Vernier Caliper (cont.)

Different L.C in vernier caliper

All values are in cm



Reading vernier caliperProf.H M Prajapati & Prof. A R Sankhla


Type A vernier caliperProf.H M Prajapati & Prof. A R Sankhla


Type B vernier caliperProf.H M Prajapati & Prof. A R Sankhla


Type C vernier caliperProf.H M Prajapati & Prof. A R Sankhla


Material

Steel

Hardness:

650 HV min.

Range:

0-125, 0-200, 0-250, 0-300, 0-500, 0-750, 0-1000, 750-1500, 750, 2000 mm

Flatness 0.05 mm for nominal

lengths upto 300 mm

Straightness 0.01 mm for measuring

range of 200 mm

Precautions in use

Errors


Vernier Height Gauge



Base

Flatness: 0.005 mm

Beam

Parallelism of measuring jaw by 0.005 mm/ 10 mm projection of scriber when 1 kg is applied at maximum height of scriber

Straightness of guiding edge

0.02 (250), 0.04(500), 0.06(750), 0.08(1000)

Flatness of beam face

0.04 (250), 0.06(500), 0.10(750), 0.12(1000)

Perpendicularity

0.04 mm /100 mm



Measuring jaw and scriber

Parallelism of jaw face with base: 0.008 mm

Graduation

Thickness of graduation: 0.05 to 0.1 mm

Length of graduation: 2 to 3 times the width of interval between adjacent lines

Measure of height

Slider

Good sliding fit


Vernier Depth Gauge


Dial Caliper (cont.)


Digital Caliper


Principal of Micrometer

Micrometers work on the principle of screw and nut

When a screw is turned through nut by one revolution, itadvances by one pitch distance

If circumference of the screw is divided into number ofequal parts say ‘n’ , its rotation through one division willcause the screw to advance through (pitch/n) length

Thus the minimum length that can be measured by sucharrangement will be ( pitch/n)

Micrometer


Least count of Micrometer

L.C = (Pitch of the thread / total numbers of divisions

on the thimble)

= ( Pitch / n)

= ( 0.5 / 50)

L.C = 0.01


Micrometer



Micrometer

Frame

Material

Cast steel, steel or malleable cast iron, light alloy

Stiffness: 1 kg force should not change distance by

1.5µm for 0-25 range, 2µm for 25-50 range

Anvil and spindle

About 3mm protrusion from frame

Tungsten carbide tip

Ratchet driver

0.5 to 1 kgf

Thimble and barrel

Adjusting nutProf.H M Prajapati & Prof. A R Sankhla

How to read Micrometer?

Reading a micrometer

Zero error


VERNIER MICROMETER

Vernier micrometerProf.H M Prajapati & Prof. A R Sankhla

Use of Ratchet Mechanism

To maintain uniform contact pressure less than 1 kgf.

It completely remove the error because of lack of sense of

feel.



Precaution used for micrometer

The micrometer should be wiped clean and free from oil,dirt, dust etc.

Start with zero setting on micrometer. Use spanner tocorrect the error with slight rotation of barrel.

Micrometer dimension is set slightly larger than the size ofPart whose dimensions to be measured and part is slid overthe contact surfaces of micrometer. After this thimble isturned till the measuring tip just touches the part and thefinal movement should be done by ratchet.

The micrometers are available is various sizes and ranges,select appropriate micrometer.


Errors

Anvil and spindle tips should be parallel and flat to each other.

Axis of both should be coincide to each other.

Zero error.

Wear of threads.


Depth micrometer


Inside micrometer

spacing Collar Extension rods


Inside Micrometer

Main PartsMeasuring Head



Possible ranges with extension bar


SLIP GAUGE

Johannsen gauges

Cross-section:30 mm×09 mm

Classification

As per accuracy

Master slip gauge AA: ±2µ/m

Reference slip gauge A: ±4µ/m

Working slip gauge B: ±8µ/m

As per grade

Grade 2: Workshop grade

Grade 1: Tool room work (setting up sine bar & Dual Gauge, checking gap gauges)

Grade 0: Inspection grade (Inspection Dept.)

Grade 00: Calibration of Grade 2


SLIP GAUGE


SLIP GAUGE

Size

Upt0 10 mm: 30 mm×9 mm

Above 10 mm:35 mm×9 mm

Grades

Grade 0, Grade I, Grade II

Material

High grade steel with coefficient of thermal expansion (11.5±1.5)×10-6 per degree Celsius between 10C and 30C

Hardness: 800HV

Indian standard on slip gaugesProf.H M Prajapati & Prof. A R Sankhla

SLIP GAUGE

Wringing of slip gaugesProf.H M Prajapati & Prof. A R Sankhla

0.00635 microns

Slip Gauge set as per Indian Standard

M45/1 & M86/1


Selection of slip gauges for required dimension

Make a stake of 55.289

Always start with the last decimal place and deduct this

from the required dimension. For example, let’s the

dimension is to be built up is 55.289.

Here for last decimal place of 0.009, select 1.009 mm

slip gauge. Now dimension left = 55.289-1.009 = 54.28

mm

Select next smallest figure in the same way, find the

remainder and continue this until the required

dimension is completed


In our example second decimal place is 1.08,select

1.08 mm slip gauge

Now remainder = 54.28 -1.08 = 53.2mm

Now select 1.2 mm and 52 mm is the remaining

dimension.

Now select 2 mm slip gauge so remainder 50 mm. 50

mm slip gauge is available directly.

Thus we have 50+2+1.2+1.08+1.009 = 29.758 mm


Care & Use of slip Gauges.

Surfaces should be covered with petroleum jelly or othercorrosive resistance coatings.

When the gauges are not in use they should be kept in their casewith size.

The gauges should be used in air conditioner rooms free fromdust and dirt.

The fingering/Handling of lapped faces should be avoided as faras possible that may corrode surfaces due to natural acid in theskin.

The working surfaces should never be placed on surface plate.

Use standard wringing process to make stake of gauges.

The gauges should never be left wrung together for anunnecessary length of time. This may lead to micro cold weldingwhich may cause pitting of surface when they are separated.


SURFACE PLATE

Purpose Datum simulator for linear and angular

measurement Test degree of flatness of other surfaces

Material Properties Rigidity Wear resistance Hardness Corrosion resistance Capable to take high surface finish

Material Cast Iron Granite Glass

Manufacturing of plate Straightness

0.08 mm per meter

Flatness ± 0.002 to ±0.005 (150 mm diagonal) ± 0.02 to ±0.04 (2000 mm diagonal)


Care & Use of Surface Plate

Before and after use of surface plate, it should be wiped clean

from dust and other particles.

Surface plate should be placed in stirred atmosphere under

constant temperature control. Keep it away from direct sunlight.

Load should be distributed over working surface.

Full area of plate should be utilized. Do not concentrate on

particular area.

The excess metal due to burrs on the surface of CI surface plate

should be removed.

Flatness should be checked occasionally.

Protect it against damage by direct falling of heavy objects.

When not in use, it should always be kept oil lubricated in cover.


ANGLE PLATE

Material

Cast Iron

Purpose

Accessory to surface plate



V-BLOCK

Purpose

To hold the object

Checking roundness

Marking centers

Material

Cast Iron

Angle

90, 120


FEELER GAUGE

Purpose To measure the

gap/clearance between two flat parallel surfaces.

Thickness 0.03 to 1 mm

Width 10 mm at heel side

6 mm at tip

Set Eight blades

0.03 to 0.1 in steps of 0.01


Sr No No. of

blades

Thickness of blades in mm

1 8 0.03 to 0.1 in steps of 0.01

2 9 0.03, 0.03, 0.04, 0.04, 0.05, 0.05, 0.06, 0.07, 0.09

3 16 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35,

0.4, 0.45, 0.5

4 10 0.03, 0.04, 0.05, 0.06, 0.07, 0.1, 0.15, 0.2, 0.4, 0.5

5 14 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.75, 1.0

6 11 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.4, 0.75, 1.0

7 11 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0


RADIUS GAUGE


THREAD PITCH GAUGE


STRAIGHT EDGE

Purpose Checking straightness and

flatness

Material Steel (2 m) Cast Iron (3 m)

Grade Grade A

Scraping 0.001 mm/100 mm

Grade B Milling 0.002 mm/100 mm

Working length and total length


STRAIGHT EDGE (CONTD.)


Combination Set


COMBINATION SET


COMBINATION SET


SMALL BORE GAUGE



TELESCOPIC GAUGE


PIN GAUGE METHOD TO MEASURE BORE DIAMETER


PIN GAUGE METHOD TO MEASURE BORE DIAMETER


Four Ball Method



Parallax error numerical

Chapter 1 Introduction

Worked Examples

Q 1.8

Book: Engineering Metrology by R K Jain


Transfer from line standard to end standard

Chapter 3:

Topic 3.5.2

Book: Engineering Metrology by R K Jain

Solved Examples:

Q. 3.3 and 3.4


Documents

CLEANING & DEBURRING EQUIPMENT GAUGE Johannsen gauges Cross-section:30 mm×09 mm Classification As per accuracy Master slip gauge AA: ±2µ/m Reference slip gauge A: ±4µ/m Working