Lesson 2/Learning Event 1
This type of caliper uses a vernier scale. This scale, Figure 22, consists
of a short auxiliary scale usually having one more graduation in the same
length as the longer main scale.
The vernier caliper consists of a L-shaped frame, the end of which is a
fixed jaw. The long arm of the L is inscribed with the main true scale or
fixed scale. The sliding jaw carries the vernier scale on either side. The
scale on the front side is for outside measurements; the one on the back is
for inside measurements.
On some vernier calipers, the metric system of
measurement is placed on the back side of the caliper in lieu of a scale
used for inside measurements. In such cases, add the thickness of the nibs
to the reading when making inside measurements.
The tips of the jaws are formed so that inside measurements can be taken.
The inside scale automatically compensates for the thickness of the
The length of the jaws range from 1 1/4 inches to 3 1/2 inches. The minimum
inside measurement, using the smallest caliper, is 1/4 inch or 6
Vernier calipers are made in standard sizes of 6, 12, 24, 36, and 48 inches,
and 150, 300, 600, and 900 millimeters. The jaws of all vernier calipers,
except the larger sizes, have two center points, which are particularly
useful in setting dividers to exact dimensions.