Types
of Vernier Caliper: Parts, Uses, Zero Error, Least Count, and Working Principles
A
Vernier caliper is referred to as equipment that is commonly used for a variety
of accurate measurements and is not necessarily related just to the
engineering manufacturers.
There
are three types of Vernier calipers that are commonly used in the laboratory in
order to measure the lengths of small objects accurately and precisely that
cannot be done using a meter scale or any other equipment.
Very
accurately that's the reason it is also called a Precision Measuring
Instrument.
It
was invented by French mathematician Pierre Vernier in 1631.
So,
let’s scroll down to learn more about the kinds of Vernier calipers.
1. Type
A,
2. Type
B,
3. Type
C,
The
important use of any Vernier caliper is to measure the internal as well as
the external diameter of an item. The word caliper is derived means any device
with two jaws that are used to determine the diameters of items. This is the
device that is well known for obtaining accurate measurements which are highly
desired for scientific experiments.
The
principle that a Vernier caliper works is that whenever there are two scales or
divisions that are slightly different in size, then the difference within them
is used so that the accuracy of the measurements is increased.
Main Parts of Vernier Caliper
As
Vernier caliper is high in demand at places where there is a requirement for
high-accuracy measurements. So here comes a need to properly know the elements
of Vernier caliper that are mentioned below. So, the main elements of the
Vernier caliper are as follows:
1. Main
Scale
2. Vernier
scale
3. Lock
Screw
4. Thumbscrew
5. Depth
Rod
6. Fixed
Jaw
7. Sliding
Jaw
1.
Main Scale:
Vernier
caliper mostly consists of two steel rules that can slide along with each
other. One is observed to be a long rectangular metal strip that has a fixed
jaw on one end and graduates in inches at its upper end, and a few centimeters
at its lower end which is known to be the main scale. The main scale can be
seen on the solid L shape frames, on that the centimeters.
Markings
are dividing on into 20 parts so that a small division is equal to 0.05 cm.
This allows best in the generally used measuring techniques along with the
direct measurements using the line graduating the methods.
2.
Vernier Scale:
There
is one more, a small rectangular metal strip that is graduated along with a
special relation to the main scale which is termed the Vernier scale, and
slides over this long metal strip when it has a jaw that is similar to that of
the main scale. There are two jaws that are found on the Vernier caliper one is
the upper jaw and the other is the lower jaw. These are the jaws that are used
together to hold the object tightly during the measurements of its length that
is impossible to use a meter scale.
The
external jaw that is also known as the lower jaws is properly used to measure
the diameter of a spherically or a cylinder whereas the internal jaws or the
upper jaws are the ones that are properly used to measure the internal diameter
of a hollow cylinder. There is a metal strip observed that is attached at the
back of the Vernier caliper and is helpful in measuring the inner depth of a
cylinder.
Working Principles of Vernier Caliper
A
scale cannot the measurements of any objects that are smaller than 1mm whereas
a Vernier caliper can be measuring these objects up to 1mm. As is well known
when the Vernier caliper is found to have two scales the main scale and the
Vernier scale, both of these make arrangements to measure very lighter lengths
like that of 0.1mm and so on. The main
scale is found to have at least a count of 1mm whereas the Vernier scale has
the least count of 0.9mm. 10 units of the main scale are equivalent to 1cm
whereas 10 units of the Vernier scale are equivalent to 0.9mm.
The
unit of the Vernier scale is a millimeter. This is termed the main difference
between the main scale and the Vernier scale is 0.1 mm and is also referred to
as the working principles of the Vernier caliper.
Least Count
The
difference between the values of one main scale division and that of a Vernier
scale division is referred to as the least count of the Vernier caliper. The
least count of the Vernier caliper is referred to as the smallest value that
can be measured from this instrument. In the order to calculate the least count
of a Vernier caliper, the value of one main scale division needs to be divided
by the total number of divisions present on the Vernier scale.
For
example, the value of one main scale division is 1mm and if the total number of
divisions on the Vernier scale is to find to be 10mm then the least count is
0.1mm. Therefore, the least count is known to be the lightest distance that can
be measured from the instrument named the Vernier caliper.
Zero Error in Vernier Caliper
A
zero error in the Vernier caliper is called a mathematical error due to, the
zero of the Vernier scale does not get coincide with the zero of the main
scale. In case the zero mark on the Vernier scale does not coincide with the
zero mark on the main scale, then the error that is found to occur is termed a
zero error. Zero errors are found in the 2 types these are as follows:
·
Positive zero
error
·
Negative zero
error
1.
Positive Zero Error
In
the case of positive zero error, if these jaws are brought together the seer
can observe the zero of the Vernier scale will be the head of the main scale
zero. It can be said that the zero of the Vernier scale is on the right side of
the main scale zero. In both cases either it is the head of the main scale zero
or it would be at the right side of the main scale zero. This is called the
zero error which is positive.
2. Negative Zero Error
In
the case of negative zero error, once both the jaws are brought together the
seer can observe zero of the Vernier scale that is at the back side of the main
scale zero or can also be at the left side of the main scale zero. So in case,
the Vernier scale zero is found at the backside or to the left of the main
scale zero then in both cases, the zero error is called to be the negative
error.
3. No Zero Error
In
no zero error, once both the jaws are brought together the seer can observe
zero of the Main scale coinciding with the zero of the Vernier scale. If they
are exactly in a straight line then the Vernier caliper is called to be free
from zero error or can be called that there is no zero error in this Vernier
caliper.
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Types of Vernier Caliper
The different types of Vernier Calipers are mentioned
below:
1. Flat
edge Vernier caliper
2. Knife
edge Vernier caliper
3. Vernier
depth gauge
4. Flat
and Knife edge
5. Vernier
height gauge
6. Vernier
gear tooth caliper
7. Vernier
dial caliper
1.
Flat Edge Vernier Caliper:
Flat
edger Vernier calipers are referred to as the kinds of Vernier that are used
for normal functions like the outer measurement of length, thickness, width,
and diameter. As its edge is found to be of a special kind, the inner
measurements can also be taken along with it. Whereas from that measurements,
the width needs to be subtracted. This kind of measurement is often written on
the jaw otherwise it should be measured with a micrometer.
2.
Knife Edge Vernier Caliper:
Knife
edge Vernier calipers are the Vernier that has the edges like a knife. This
Vernier caliper is mainly used at places where there are narrow spaces, the
distance of holes of I bolt, etc. Its importance is due to the thin edge of its
jaw that wears out quickly and starts giving inaccurate measurements. This kind
of Vernier should be used just a little and carefully.
3.
Flat and Knife Edge Vernier Caliper:
Flat
and knife-edge Vernier calipers are called to those which have their jaw like
an ordinary Vernier caliper on one side whereas have knife-edge jaw on the
other side. These types of Vernier calipers can be used to perform all kinds of
jobs, as they can measure everything easily.
4.
Vernier Gear Tooth Caliper:
The
Vernier gear tooth caliper is called a special kind of instrument that is made
from a combined form of two Vernier calipers. This kind of Vernier consists of
two separate scales, one is the vertical scale and the other is the horizontal
scale. In the Vernier caliper, the thickness of a tooth of gear can be taken
from the pitch circle or it can be said that the Vernier caliper is used to
measure various parts of the gear.
5.
Vernier Depth Gauge:
The
Vernier depth gauge is called an instrument that is used for the measurement of
the depth of the slot of any particular job like its hole or groove. This kind
of Vernier is almost similar to that of a Vernier caliper and the reading is
also taken in the same way but it is found to have a flat-shaped base that is
used instead of a jaw.
The
depth gauge is made using a thin beam like a narrow rule and the main and
Vernier scale is also found in either inch or metric system. The main purpose
of such Vernier is that the observer can take measurements of three kinds with
it:
· The main scale can
be found to be marked in parts of inches and is also divided into 64
sub-sections.
· The other end can
be found having 40 sub-sections and every fourth line being slightly bigger. It
contains the local size with the minimum measurements of 0.001 and is taken
with the help of a Vernier scale.
The
readings are found in mm which can take the minimum measurements of 0.02 mm
along with the help of a Vernier scale.
6.
Vernier Height Gauge:
Vernier
height gauges are used for making accurate measurements of height or for any
marking with the highest required accuracy. This kinds of instrument are
quite similar to that of a Vernier caliper whereas it is used by attaching some
of the additional associates. The beam can be found fixed on the base in length
form. Also, the off-set scriber is fixed on the beam itself using that the
height of a job is measured or the marking is done. These are further
categorized into two different types:
·
Solid Base
·
Moveable Base
In
the solid type of Vernier there is no facility to set the beam or base as per
the requirement of the site whereas, in the moveable base Vernier, this
facility can be found to exist. This is the kind of Vernier height gauge that
is in the form of a set and has a base Vernier caliper, offset scriber fixing
screw, etc. These are the types of Vernier height gauges that can be used as an
ordinary Vernier caliper by partnering with its base. In order to use both
types of Vernier height gauges, it is mandatory to keep in mind the following
points:
·
Ensure using it on
a plain surface of the jobs.
·
To be used on a
surface plate only.
·
The readings
should be noted down.
·
Avoid giving
excessive pressure while marking to avoid breakage.
·
To be used only
for précised marking or measurements.
7.
Vernier Dial Caliper:
In
a Vernier caliper, there are be find chances of mistakes as far as reading is
concerned. So to escape these things, nowadays Vernier dial calipers are being
used that have replaced the Vernier scale and also contain a graduation dial in
order to escape the reading errors.
Similar
to Vernier calipers, these are the instruments that can be used to measure the
dimensions in inches as well as in millimeters. Similar to a dial test
indicator, a rack and a pinion are also used in these venires. The rack can be
found to be on the main scale which is connected to the pinion of the dial. In
this type of movable jaw is the one that moves by the thumb roller is in order
to take the reading, for this, there needs to be a check on how many main and
sub marks an inch of the bevel edge of the movable jaw that has crossed and
added the reading.
Description:
You
must be able to find a sliding jaw that is located and is found responsible for
running on the main scale along with the guiding surface and accompanied by a
Vernier scale, wherein it is found to have a measuring tip on its left side. If
there are found two measuring tip surfaces are found to be in contact with
each other then the scale is found to have a zero reading. In the initial
times, the entire movable jaw assembly needs to be adjusted so that both the
measuring tips can touch the parts that are in need to be measured. After that,
lockout B is tightened properly. The final adjustments are those that depend
upon the sense of correction factor and are made simply by adjusting the screws
so that the part that contains locking nut A and sliding jaw can be moved
properly, the adjusting screw is found rotating on a screw that is in a way
fixed to the movable jaw.
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