Title: CENTRE OF EXCELLENCE
1CENTRE OF EXCELLENCE
- INDUSTRIAL TRAINING INSTITUTE
- PALANA
TRADEPMBT
MODULE1
2- MODULE1BASIC FITTING AND
- MEASUREMENT
3- LESSON NO 1
- METROLOGY
-
- METROLOGY is define as a measurement of length
and angles and other such quantities which are
expressed in linear and angular measurement.
4IMPORTANTCE OF METROLOGY
- To achieve quality control in production
- To achieve up to date production, knowledge of
The measurement require. - To reduce rejection with the help of quality
control. - To develop inspection procedure .
- To calibrate measuring instrument time to time
5TERMS USED IN METROLOGY
- SPECIFICATION
- Every product and part have some
certain characteristics .It gives certain
thoughts of that particular product. Its called
specification. It gives easy to understand
production method. - STANDARD
- Standard is define as , it is a physical
quantity which is established by higher authority
or organization .This standard is reliable and
acceptable to measure physical quantity. Ex.
METER
6LENGTH STANDARD
- THERE ARE TWO STNDARD SYSTEM TO MEASURE
LENGTH - 1.BRITISH SYSTEM INCH,FOOT,YARD
- 2.METRIC SYSTEM MM,CM,METER
7LESSION NO2
- UNIT OF LINEAR MEASUREMENT
- 1.British system mile
- yard
- foot ()
- inch ()
- 2.metric system kilometer
- meter
- decimeter
- centimeter
- millimeter
- 3.S.I. System meter
-
-
8CONVERSION
- BRITISH SYSTEM 12 inch1 foot
- 36 inch1 yard
- 3 foot1
yard - 1760 yard1mile
- METRIC SYSTEM1000micron1mm
-
10mm1cm - 10cm
1decimeter -
10decm1meter -
1000meter1kilometer
9S.I.SYSTEM
- As per S.I.System fundamental unit of length
is METER - 1.METER1000MM
- 1CENTIMETER10MM
- 1MILIMETER1000MICRON
- 1MICRON0.001MM
10LESSION NO3ORDINARY MEASURING INSTRUMENT
-
- THERE ARE TWO TYPE OF MEASURING INSTRUMENT 1.
DIRECT MEASURING - Steel rule
- Ordinary
depth gauge - Protector
gauge - 2. IN DIRECT MEASURING
- Out side
caliper - Inside
caliper - Jenny
caliper
11ENGINEERING STEEL RULE
- When dimension are given in a drawing
without any indication about the tolerance ,it
has to be assumed that measurement are to be made
with steel rule. - MATERIL It is made from spring steel or
stainless steel
12 CONSTRUCTION
- The edges are accurately ground to
form straight edge. - The surface of steel rule is satin
chrome finished to reduce glove and prevent
rusting. - ACCURACE Reading accuracy of steel rule is
0.5mm in metric system and 1/64 in British
system - SIZE OF STEEL RULE Steel rule are available
in different length .The common size being
150mm,300mm,600mm. - The steel rule graduated in
- 10 mm,5mm,1mm,0.5mm
13MEASURING WITH A STEEL RULEThe figure given
below shows the method of using a try square and
steel rule for accurate measurement. For accurate
readings, it is necessary to read vertically and
avoid errors arising out of parallax.
14IMPORTANT SAFETY
- For maintaining the accuracy of a
steel rule ,it is important to see to it that its
edges and surfaces are protected from damage and
rust. - Do not place a steel rule with any
cutting tools. Apply a thin layer of oil when not
in use.
15CALIPERS
- Caliper are simple measuring
instruments used to transfer measurement from a
steel rule to objects, and vice versa. - Calipers are of different types
depending on the type of the joint and the shape
of the leg .
16TYPES OF JOINTS
The commonly used caliper are firm joint
calipers and spring joint caliper FIRM JOINT
CALIPER In the case of firm joint calipers ,both
legs are pivoted at one end. To take measurem-ent
of a workpiece,the caliper is opened roughly to
the required size. Fine setting is done by
tapping the caliper lightly on a wooden surface.
17SPRING JOINT CALIPER
For this type of calipers, the legs are
assembled by means of a pivot loaded with a
spring. For opening and closing the caliper
legs, a screw and nut are provided. Spring
joint calipers have the advantage of quick
setting. The setting made will not change un less
the nut is turned. The size of a caliper is
specified by its length ,which is the distance
between the pivot centre and the tip of the leg
18TYPES OF LEG
Out side and inside calipers are
differentiated by the shape of the legs.
Calipers used for out side measurements
are known
as out side calipers. The calipers used for
internal meas-urements are known as in side
caliper. Caliper are used along with steel
rule ,and the accuracy is limited to 0.5 mm
parallelism of jobs etc.can be checked with
higher accuracy by using calipers.
OUT SIDE
IN SIDE
19LESSON NO 4PRECISION MEASURING INSTRUMENT
- TYPES OF MEASURING INSTRUMENT
- 1.VERNIER CALIPER.
- 2.VERNIER DEPTHGAUGE
- 3.VERNIER HEIGHT GAUGE
- 4.MICRO METER OUT SIDE
- 5.MICRO METER IN SIDE
- 6.MICRO METER
- DEPTH GAUGE
- 7.DIAL CALIPER
- 8.DIAL INDICATOR
20VERNIER CALIPER
- A vernier caliper is a precision measuring
instrument. It is used to measure up to an
accuracy of 0.02 mm . - MATIRIAL It is made from nickel chromium steel
- USE Vernier caliper is use to measure out side
,inside, depth of the size.
21 PARTS OF A VERNIER CALIPER
FIXED JAWS(1 AND 2) Fixed jaws are part of the
beam scale one jaw is used for taking external
measurement ,and the other for internal
measurement.
22PARTS OF VERNIER CLIPER
- MOVABLE JAWS Movable jaws are part of the
vernier slide. One jaw is used for external
measure-ments,
23PARTS OF VERNIER CALIPER
- VERNIER SLIDE A vernier slide moves over the
beam and can be set in any position by means of
a spring loaded thumb leven.
24PARTS OF VERNIER CALIPER
- BEAM The vernier slide , and the depth bar
attached to it, slide over the beam. The
graduation on the beam are called the main scale
division.
25PARTS OF VERNIER CALIPER
- DEPTH BAR The depth bar is attached to the
vernier slide and is used for depth measurement.
26PARTS OF VERNIER CLIPERS
- THUMB LEVER The thumb lever is a spring loaded
lever which helps to set the vernier slab in any
position on the beam scale.
27 PARTS OF VERNIER CALLIPER
- VERNIER SCALE The vernier scale is the
graduation marked on the vernier slide. The
divisions of this scale are called vernier
divisions.
28PARTS OF VERNIER CALIPER
- MAIN SCALE Main scale graduations or divisions
are marked on the beam.
29 SIZE OF VERNIER CALLIPER
- Vernier calipers are available in size of 150 mm,
225 mm, 900 mm and 1200 mm. The selection of the
size depends on the measurements to be taken.
Vernier calipers are precision instruments, and
extreme care should be taken while handing them.
30IMPORTANT
- Never use a vernier caliper for any purpose other
than measuring. Vernier calipers should be used
only to measure machined or filed surfaces. They
should never be mixed with any other tools. Clean
the instrument after use, and store it in a box.
31GRADUATIONS AND READING OF VERNIER CALIPERS
- Vernier calipers are available with
different accura-cies. The selection of the
vernier caliper depend on the accuracy needed and
the size of the job to be mea-sured. - This accuracy/least count is determined by
the gra-duation of the main scale and the vernier
scale division.
32DETERMINING THE LEAST COUNT
- In the verner caliper shown in fig the main
scale division (9mm) are divided in to 10 equal
parts in the vernier scale.
i.e. one main scale division 1mm
(MSD)
one vernier scale division 9/10mm
(VSD)
Least count is 1 mm-9/10 1/10mm
The difference between one MSD and one VSD0.1mm
33LEAST COUNT
- VERIER CALIPER WITH 0.02MM LEAST COUNT IS
GENERLY USED IM WORK SHOP. - In this vernier caliper main scale division
(49mm) are divided in to 50 equal part in the
vernier scale. - i.e. 1 main scale division 1 mm
- (MSD)
- 1. vernier scale division 49\50
mm - (VSD)
- Least count is 1mm 49\50 1\50 mm
- THE DIFFERENCE BETWEEN 1.MSD and 1. VSD0.02MM
34EXAMPLE OF READING
Main scale reading 35mm
The vernier division
coinciding with the main scale is the 20th
division. Value20 multiplied by
0.020.20mm. Total reading is
35mm0.20 35.20mm
35.20 mm
352.VERNIER DEPTH GAUGE
- A vernier depth is very commonly
used precision instrument for measuring depth of
holes recesses, slot and step. - Its construction and method of
reading are similar to those of a vernier
caliper.
36PARTS OF VERNIER DEPTH GAUGE
Base (1), Graduated beam (2), Clamping screw (3),
Fine adjustment mechan-ism (4) and Vernier scale
(5).
37COUNSTERACTION OF VERNIER DEPTH GAUGE
- The base (anvil) is the fixed unit and serves
as a datum for measurement. It also carries the
vernier scale and the fine adjustment mechanism. - The beam with the main scale graduations is the
sliding member or part - Fine adjustments for measurement are made after
tightening the clamping screw and the fine
adjustment mechanism.
38USES OF VERNIER DEPTH GAUGE
- While taking measurements the base
should be firmly held against the reference
surface. The relief given at the end of the beam
of some vernier height gauges is to avoid the
seating in the corners of slots and to ensure
correct reading.
39IMPORTANT
- REMOVE BURRS, IF ANY,
BEFORE TAKING MEASUREMENTS. EXCESSIVE PRESSURE ON
THE BEAM, WHILE TAKING MEASUREMENTS WILL LIFT THE
BASE FROM THE REFERENCE SURFACE AND WILL SHOW
WRONG MEASUREMENTS.
403.VERNIER HEIGHT GAUGE
- Accurate measurements are important
in layout (marking off) and inspection work. - Vernier height gauges are particularly
suitable for marking off accurate distances, and
centre location. - The graduations and readings are the
same as - those of avernier caliper.
41PARTS OF VERNIER HEIGHT GAUGE
- The main parts of a vernier height gauge
and their function are given. - 1.base
- 2. beam
- 3.vernier slide
- 4. fine setting device
- 5. vernier plate
- 6. locking screws
- 7. scriber
42ZERO SETTING OF THE VERNIER HEIGHT GAUGE
- The offset scriber permits zero
setting instrument from the datum surface. While
using a straight scriber, the zero setting of the
instrument is at a level above the datum surface.
In this case the zero setting is to be checked
using the precision round block, supplied along
with the instrument. Vernier height gauges with
which we can measure from the datum surface
without the special offset scribers are also
available. - SIZE The size of the vernier
height gauge is stated by the height of the beam.
The most commonly used size has a beam of 300 mm
height. - Vernier height gauges are used with surface
plates or other accurate flat surface.
434MICRO METER OUTSIDE
- A micro meter is a precision instrument
used to measure a job, generally within an
accuracy of 0.01mm.Micrometer used to take the
outside measurements are know as outside
micrometer.
44PARTS OF MICROMETER OUTSIDE
FRAME The frame is made of drop forge steel or
malleable cast iron. All other part of the
micrometer are attached to this. BARREL/SLEEVE
The barrel or sleeve is fix to the frame. The
datum line and graduation are marked on this.
45PARTS OF MICROMETER OUTSIDE
- SPINDLE One end of the spindle is the measuring
face. The other end is threaded and passes
through a nut. The threaded mechanism allows for
the forward and backward movement of the spindle. - SPINDLE LOCK NUT The spindle lock nut is used to
lock the spindle at a desired position.
46PARTS OF MICROMETER OUTSIDE
- THIMBLE On the beveled surface of the thimble
also, graduation is marked. The spindle is
attached to this. - ANVIL The anvil is one of the measuring faces
which is fitted on the micrometer frame. It is
made of alloy steel and finished to a perfectly
flat surface.
RATCHETSTOP The ratchet stop ensures a uniform
pressure betw-een the measuring surface.
47GRADUATION OF MICROMETER
- WOKING PRINCIPLE The micrometer works on the
principle of screw and nut .The longitudinal
movement of the spindle during one rotation is
equal to the pitch of the screw. The movement of
the spindle to the distance of the pitch or its
fractions can be accurately measured on the
barrel and thimble.
48GRADUATION
- In metric micrometer the pitch
of the spindle thread is 0.5mm. Thereby ,in one
rotation of the thimble, the spindle advances by
0.5 mm. - On the barrel a 25 mm long datum
line is mar-ked. This line is further graduated
to millimeters and half millimeters (i.e. 1 mm
0.5 mm).
49GRADUATION
The graduations are numbered as
0,5,10,15,2025 mm The circumference of the bevel
edge of the thimble is graduated in to 50
division and marked 0-5-10-1540-50 in a
clockwise direction. The distance moved by the
spindle during one rotation of the thimble is 0.5
mm. Movement of
One division of the thimble 0.5 1/50
0.01 mm
ACCURACY 0.01mm
50READING WITH OUTSIDE MICROMETER
- RANGES OF O.S. MICROMETER Outside micrometer
are available in ranges of 0 to 25mm, 25 to 50mm,
50 to75mm, 75 to 100mm,100to125mm, 125 to 150mm.
For all range of micrometer, the graduations
marked on the barrel is only 0-25 mm.
51READING OF OUT SIDE MICROMETER
First note the minimum rang of the outside
micro Meter . While measuring with a 50to75mm
micrometer, note it as 50mm.Then read the barrel
graduation. Read the value of the visible line on
the left of the thimble edge. See below fig. i.e.
main div. 13.00 sub div.0.5 mm so, total
13.50mm. Next read the thimble gradua- tions in
line with the barrel datum line, 13th div.
Multiply this value with 0.01mm, 13
0.01mm0.13mm so, barrel reading13.50
thimble reading00.13 total 13.63 mm
52DEPTH MICROMETERS
- CONSTRUCTIONAL FEATURES The depth micrometer
consists of a stock on which a graduated sleeve
is fitted. - The other end of the sleeve is threaded with a
0.5 mm pitch v thread. - A thimble which is internally threaded to the
same pitch and from, mates with the threaded
sleeve and slides over it. - The other end of the thimble has
- an external step machined and threaded
- to accommodate a thimble cap.
53CONSTRUCTIONAL FEATURES
- A set of extension road is generally supplied. On
each of them the range of sizes that can be
measured with that road, is engraved as
0-25,25-50,50-75,75-100, 100-125,125-150. This
extension road can be inserted in side the
spindle and the sleeve. The extension rods have a
collar-head which helps - the road to be held firmly.
54CONSTRUCTIONAL FEATURE
The measuring faces of the stock and the
rods are hardened, tempered and ground. The
measuring face of the stock is perfectly machined
flat. The extension roads may be removed and
replaced according to the size of depth to be
measured.
55GRADUATION
On the sleeve a datum line is marked for a length
of 25 mm.this is divided into 25 equal part and
graduated,each line representing one millimeter.
each
Fifth line is drawn a little longer and numbered.
Each line representing 1mm is further subdivided
into two equal part.Hance each sub-division
represents 0.5 mm. The graduation are numbered in
the reverse direction to that marked on an
outside micrometer
56GRADUATION
- The zero graduation of the sleeve is on the top
and the 25mm graduation near the stock. The bevel
edge of-
the thimble is also graduated. The circumference
is equally divided into 50 equal parts and every
5th division line is drawn a little longer and
numbered. The numbering is in the reverse
direction and increases from 0, 5, 10, 15, 25,
30, 35, 40, 45 and 50 (0).
57LEAST COUNT
- The advancement of the extension rod for one full
turn of the thimble is one pitch which is 0.5 mm
Therefore the advancement of the extension rod
for one division movement of the thimble will be
equal to 0.5/50 0.01mm. This will be the
smallest measurement that can be taken with this
instrument, and so, this is the least count of
this instrument.
58USES OF DEPTH MICROMETER
- Depth micrometers are special micrometers used to
measure - The depth of holes.
- The depth of grooves and recesses
- The heights of shoulders or projections.
59LESSION NO5COMBINATION SET
60TYPES OF CUTS
- basically there are four types. Single cut,
double cut, rasp cut and curved cut
61SINGLE CUT FILE
- A single cut file has rows of teeth cut in one
direction across its face. The teeth are at an
angle of 60 to the center line. it can cutchips
as wide as the cut of the file. Files with this
cut are useful for filing soft metals like brass,
aluminum, bronze and copper.