Lesson 1/Learning Event 1
Learning Event 1
Micrometers are used for measurements requiring precise accuracy. They are
made in various shapes and sizes, depending on their intended purpose. They
all have a precision screw adjustment offering great measuring accuracy.
Micrometer Caliper (Outside)
The micrometer caliper, Figure 1, is the most common micrometer. It has a
range of 0 to 1 inch and is graduated to read in thousandths of an inch or
in units of the metric system, from 0 to 25 millimeters by hundredths of a
millimeter. It may or may not have--
a. A stainless steel frame to resist corrosion or tarnish.
b. A ratchet for applying a constant measuring pressure.
c. A special vernier scale for reading tenths of thousandths of an
d. A clamp ring or locknut for clamping the spindle to hold a setting.
e. Cemented carbide tips on the measuring anvils to reduce wear.
The frame can be smaller to the extent that the range of the caliper is only
0 to 1/2 inch; or, it can be larger so that the range is 23 to 24 inches.
The head has a constant range of 0 to 1 inch. The shape of the frame may be
varied to adapt it to the physical requirements of some types of work. For
a. The frame back of the anvil may be cut away to allow the anvil to be
placed in a narrow slot.
b. The frame may have a deep throat to allow it to reach into the
center sections of a sheet (sheet metal or paper gage).
c. The frame may be in the form of a base so that the gage can be used
as a bench micrometer.