This document provides information about micrometer screw gauges and how to use them to precisely measure small lengths. It describes the key components of a micrometer, including the frame, anvil, barrel, lock nut, screw, spindle, and thimble. It explains that a micrometer can measure lengths as small as 0.01 mm. It also discusses the concept of zero error and how to correct measurements to account for any zero error.

1. Name: Agung Din Eka Hidayat
Class: Physics ICP-A
NIM : 1312441006

2. Micrometer Screw Gauge
A micrometer screw gauge is used to measure lengths of small objects
such as the diameter of human hair with a precision better than that of the
vernier calipers. Figure below shows an actual micrometer screw gauge.
The smallest length that the micrometer can measure is 0.01 mm. This is
the precision of the micrometer. The spindle will move 0.01 mm horizontally
away from the anvil when the thimble moves vertically downwards by one
small division.

3. History of the device and its name :
The word micrometer is a neoclassical coinage from Greek micros,
meaning "small", and metron, meaning "measure". The Merriam-Webster
Collegiate Dictionary says that English got it from French and that its first
known appearance in English writing was in 1670. Neither the metre nor
the micrometer nor the micrometer (device) as we know them today existed at
that time. However, the people of that time did have much need for, and
interest in, the ability to measure small things and small differences. The word
was no doubt coined in reference to this endeavor, even if it did not refer
specifically to its present-day senses.
The first ever micrometric screw was invented by William
Gascoigne in the 17th century, as an enhancement of the vernier; it was used
in a telescope to measure angular distances between stars and the relative
sizes of celestial objects.
Henry Maudslay built a bench micrometer in the early 19th century
that was jocularly nicknamed "the Lord Chancellor" among his staff because it
was the final judge on measurementaccuracy and precision in the firm's work

4. A micrometer is composed of:
Frame
The C-shaped body that holds the anvil and barrel in constant relation to each other. It is
thick because it needs to minimize flexion, expansion, and contraction, which would distort
the measurement.
The frame is heavy and consequently has a high thermal mass, to prevent substantial
heating up by the holding hand/fingers. It is often covered by insulating plastic plates which
further reduce heat transference.
Anvil
The shiny part that the spindle moves toward, and that the sample rests against
Sleeve / barrel / stock
The stationary round part with the linear scale on it. Sometimes vernier markings.
Lock nut / lock-ring / thimble lock
The knurled part (or lever) that one can tighten to hold the spindle stationary, such as when
momentarily holding a measurement.
Screw
(not seen) The heart of the micrometer, as explained under "Operating principles". It is
inside the barrel. (No wonder that the usual name for the device in German
is Messschraube, literally "measuring screw".)
Spindle
The shiny cylindrical part that the thimble causes to move toward the anvil.
Thimble
The part that one's thumb turns. Graduated markings.
Ratchet stop
(not shown in illustration) Device on end of handle that limits applied pressure by slipping at
a calibrated torque.

6. When the anvil and spindle are closed, the zero mark on the circular scale
coincides with the horizontal line on the main scale. If it doesn’t, the
discrepancy is known as zero-error (look At the figure) and has to be
subtracted from the value obtained by measurement.
Zero error is an example of a systematic error that will cause the
measured value to be either too large or too small when compared to the
true value.
Correct measurement = Actual measurement – zero error

7. Treatment of zero-error is shown below.

8. To find the average diameter of a uniform rod, we take readings at
several positions (at least 3).
Average Diameter = (X1 + X2 + X3 ) / 3
Reading for X1
Reading for X2
Reading for X3

9. Techniques in measuring small quantities without using special instruments.
1) Thickness of 1 piece of paper
- Use a metre rule to measure the thickness of 100 sheets of paper.
- Thickness of 1 sheet of paper = Total Thickness / 100.
2) Diameter of a piece of wire
- Wind the wire around a thin rod or a pencil to form a tight coil, say 18 turns
(Figure 13). Use a metre rule to measure the length of the coil, d cm.
- Diameter of the wire = d / 18

10. THANKS FOR YOUR ATTENTION ^^