Using the Vernier Caliper and the
Micrometer
A Powerpoint Presentation
by
Mr. Fernando D. Nolasco
Try this.
• When you use your ruler, how do you
measure the diameter of a PENCIL OR A
PEN TUBE?
A Better Way
Vernier Caliper
Parts of a Vernier Caliper
Internal Jaws
External Jaws
Parts of a Vernier Caliper
Two Scales Are Better Than One
The vernier caliper has two scales: the main
scale and the vernier scale
The main scale is similar to the scale found on
an Orion plastic ruler, graduated in
millimeters (mm).
The vernier scale is graduated into 0.050 mm
marks.
Main Scale
Vernier Scale
0.000, 0.050 0.100, 0.150, 0.200, 0.250, 0.300, etc
Vernier Scale
Reading the Vernier Caliper
1. Locate the “0” mark on the vernier scale.
2. Determine the last mark on the main scale
which was passed by the “0” mark of the
vernier scale. (to the left)
3. Determine which mark on the vernier scale
lines up with ANY mark on the main scale.
4. Complete the reading by adding the
doubtful figure, usually “0” and the units (i.e.
mm)
13
13
13.65
!! !!?
13.650 mm
23
23
23.70
!! !!?
23.700 mm
48
48.55
!! !!?
48.550 mm
75
75.40
!! !!?
75.400 mm
Micrometer
http://feh.eng.ohio-state.edu/tutorials/micrometer/parts.html
Two Scales Are Better Than One
The micrometer has two scales: the main or
linear scale and the rotating scale.
The main scale or linear scale is graduated into
0.500 mm marks.
The rotating scale is composed of 50 divisions,
each graduated into 0.010 mm marks.
Linear scale divided
into 0.500 mm marks
Whole Marks: 0.000, 1.000, 2.000, 3.000, etc
Half Marks: 0.500, 1.500, 2.500, 3.500 etc
Rotating scale with
50 divisions, each
equal to 0.010 mm
Like Clockwork
The micrometer scales work like the minute and
hour hands of a clock.
Each complete revolution of the minute hand
(12 numbers) advances or sets back the hour
hand by 1 number.
Each complete rotation on the rotating scale (50
divisions) advances or closes the linear scale
by 0.500 mm.
Micrometer closed - 0.000 mm
After first rotation - 0.500 mm
After second rotation - 1.000 mm
After third rotation - 1.500 mm
To get the
final reading,
Linear
Scale: simply
3.000
add the readings on the linear
and rotating scales
Rotating Scale: 0.270
!!!?
Reading: 3.270 mm
Linear scale: 6.500
Rotating scale: 0.170
! ! !?
Reading: 6.670 mm
Linear scale: 1.000
Rotating scale: 0.205
! ! !?
Reading: 1.205 mm