Using inside micrometer
with extension rod.
Figure 59. Checking diameter of pulley.
2. For probing a deep hole or in a restricted place, a handle
attachment may be used. The handle clamps on to the body of the micrometer.
to micrometer caliper.
work, hold the micrometer caliper in one hand and the inside tool in the other hand.
2. Turn the thimble of the micrometer caliper with the thumb and
forefinger until you feel the inside tool legs lightly contact the anvil and
spindle of the micrometer caliper.
3. Hold the tips of the inside tool legs parallel to the axis of the
micrometer caliper spindle.
4. The micrometer caliper will be accurately set when the inside
tool will just pass between the anvil and spindle by its own weight.
(4) Care of micrometers. To maintain a micrometer in good condition and to
preserve the accuracy of its measurements, observe the following rules of good
practice and adjusting procedures.
(a) Never store a micrometer with its anvil and spindle closed. Flat
surfaces wrung together for any length of time tend to corrode. Leave a small gap
between the anvil and spindle when storing.
(b) Oil the micrometer in only one place-the micrometer screw, and only
with a very light oil. If storing for long periods of time, cover the micrometer
with a light film of oil and wrap it in oiled paper.
(c) Never roll the thimble along the hand or arm. Likewise, holding the
thimble and twirling the frame to open or close the micrometer will cause excessive
wear on the screw.