Micrometer
screw gauge is a form of calipers used for measuring small dimensions. Screw
gauge in extensively used in the engineering field for obtaining precision
measurements. The article describes the principle and main parts of a basic micrometer
screw gauge.
Micrometer
screw gauge (or micrometer caliper) is an instrument or device for measuring
the length of an object which is more precise than a ruler and vernier caliper.
It because a micrometer screw gauge has the smallest scale of 0.01 mm. The
device is widely used in mechanical engineering for measuring small diameter,
thickness, or angles to a high degree of accuracy.
Screw gauge or
micrometer screw gauge is a measuring instrument used for precision
measurement.
Micrometer Screw Gauge
Frame of Micrometer screw gauge
Anvil
Spindle
Measuring faces
Main scale, Barrel or Sleeve
Thimble, Micrometer Scale
Ratchet stop
Spindle lock nut
Least count of Micrometer
Thimble one round.
1 mm displacement micrometer
Discount calculation
Micromete screw gauge
Micromete screw gauge
Micromete screw gauge
Micromete screw gauge
Micromete screw gauge
Objects measurement with Micrometer
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
Measuring of object with micrometer screw gauge
A
screw gauge consists of a “U” shaped metallic structure, which is attached to a
hollow cylindrical tube on one end. The hollow tube has a uniformly threaded
nut inside it. A long stud with a plane face is fitted into this nut. Exactly
on the opposite side of this nut and on the other end of the U shaped frame, a
smaller stud with a plane face is also attached. Faces of both the studs are
exactly parallel to each other. This U shaped metallic structure is known as the frame of the micrometer screw gauge. the smaller stud is known as the anvil and the longer one is known as the spindle. the anvil is the fixed part of the device, whereas the spindle moves as and when the head is moved. the frame carries both the anvil and barrel, and is also heavier than the rest of the parts. The object to be measured is held between the anvil and the spindle.
The Barrel or sleeve is connects the frame to the cylindrical tube. It is a non-movable part of the screw gauge and has a scale inscribed over it which is the main scale of the device. Moreover, it also carries the most important part of the micrometer the screw.
The
screw is the heart of the micrometer and is located inside the barrel. The
screw converts small dimensions into measurable distance using a scale. The
thimble or head is the end of the cylindrical tube and is turned to move and
adjust the spindle. The thimble carries the vernier or secondary scale. There
is one more part called the ratchet which is provided at the end of the tube.
The ratchet is kind of limiting device which applies a pressure by slipping at
a predetermined torque and thus prevents the spindle from moving further. Some
screw gauges also consist of locking devices which holds the scales at a
particular position for prevent any kind of error while taking readings.
A
micrometer screw gauge also uses two scales –main and secondary scales. The secondary scale is provided on the thimble and is
the measurement of the pitch of the screw. This means that the reading on the
secondary scale measures the distance moved by the thimble per rotation. The
scale on thimble is divided into 100 equal parts and measures hundredths of a
millimeter. The thimble scale rotates over the spindle or the main scale. The
main scale is a millimeter scale subdivided into equal parts with half a
millimeter distance. When the object is to be measured, it is placed in between
the anvil and the spindle. Readings from both the scales are taken into account
for arriving at the final measurement.
Micrometer
screw gauge is a delicate device and thus special care should be taken while
handling it. Moreover, it is also important that the micrometer is well
calibrated to prevent any kind of error in the final reading.
Precaution
Steps
The
spindle and anvil are cleaned with a tissue or cloth, so that any dirt present
will not be measured.
Watch video to Learn reading of
Micrometer screw gauge reading without the help of tutor. It is very easy to understand.
