Figure 2-30.—Depth micrometer sleeve and thimble scales.
used gives you the total depth of the hole, rcccss, or
groove that was measured.
SELECTING THE PROPER
MICROMETER
The types of micrometers commonly used are made
so that the longest movement that the micrometer
spindle or rod can make is 1 inch. This movement is
called the range; for example, a 2-inch micrometer has
a range of from 1 inch to 2 inches, and can only
measure work with a thickness or diameter within that
range. Therefore, it is necessary to first determine the
approximate size, to the nearest inch, of the work to be
measured and then select the proper size micrometer.
The size of a micrometer indicates the size of the
largest work it can measure.
CARE OF MICROMETERS
Keep micrometers clean and lightly oiled. Make
sure they are always stored in a case or box when not
in use, to protect them from damage. Never clean any
part of a micrometer with emery cloth or other abrasive.
The measuring tools that have been described in this
chapter are the ones that you, as an ABE, will routinely
usc while performing your assigned duties. You may,
however, occasionally be required to use other less
commonly used measuring tools. Some of these arc the
dial indicator, telescopic (snap) gauge, the vernier
caliper, or screw thread gauge. The description of these
tools and instructions for their use can be found in the
training manual Use and Care of Hand Tools and
Measuring Tools, NAVEDTRA 12085.
INVENTORY AND ACCOUNTABILITY
All measuring tools will be marked in some
manner, etched, stenciled, etc., to comply with standard
inventory instructions. These standard instructions may
be found in OPNAVINST 4790.15
Some measuring tools such as tapes and calipers
may be part of a specific tool box inventory. Other
precision measuring instruments such as micrometers,
snap gauges and vernier calipers will normally be
maintained in the division’s central tool room.
Regardless of the tool’s permanent location, it is always
the user’s responsibility to maintain, care for and use
the tool properly.
Damage, loss, or an improperly working tool should
be reported immediately. Loss of a tool becomes
especially critical when working on or around the
catapult or arresting gear machinery. The tool may be
“lost” in the machinery and, if not found, may cause
catastrophic damage to the equipment and serious injury
to personnel. Always double-check the inventory
ensuring every tool is accounted for
upon job
completion. The proper tools will help you maintain
your equipment but only if you maintain your tools
properly
SUMMARY
This chapter has introduced you to some of the
most often used measuring tools and the techniques for
using them. Selecting the proper tool; using and
maintaining the various tools; and inventorying the
tools have all been discussed.
By thoroughly
understanding and comprehending this chapter, you, as
an ABE, will be able to perform your daily duties more
efficiently and safely.
2-12
