TM 9-243
READING A VERNIER MICROMETER
Reading the vernier micrometer is the same as reading
the standard micrometer. An additional step must be
taken, to add the vernier reading to the dimensions.
This allows for precise measurements which are
accurate to ten-thousandths (0.0001) of an inch. This
scale furnishes the fine readings between the lines on
the thimble rather than making an estimate as you
would on a standard micrometer.
The ten spaces on the vernier (1) are equivalent to 9
spaces on the thimble (2). Therefore, each unit on the
vernier scale is equal to 0.0009 inch and the difference
between the sizes of the units on each scale is 0.0001
inch.
TO READ A MEASUREMENT AS SHOWN ABOVE:
Read highest figure
visible on barrel (3) ................................. 2 = 0.200 in.
Number of lines visible
between the No. 2 and
thimble edge (4) ...................................... 3 = 0.075 in.
The line on the thimble
that coincides with or
is nearest the
revolution or long line
in the barrel (5) ...................................... 11 = 0.011 in.
The line on the vernier
scale that coincides
with the line on the
thimble (6) ............................................ 2 = 0.0002 in.
TOTAL
= .2862 in.
7-5
