K 3500 Truck 4WD V8-305 5.0L (1985)
A full rotation will move the thimble exactly one minor division on the sleeve.
To read the micrometer you must add the measurement which is visible on the sleeve to the measurement which is showing on the thimble
In the example the sleeve measurement is 0.250 inches and the thimble measurement is 0.017 inches. The total measurement is then equal to the
two measurements combined, 0.267 inches.
NOTES
The accuracy and calibration of a micrometer can be altered easily by applying too much pressure to the spindle.
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Use the thimble to quickly rotate the spindle in until it is near the rotor.
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Use the ratchet to rotate the spindle into contact with the rotor.
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The ratchet has a built in slip which prevents excessive stress or pressure from developing.
Calibrate the micrometer regularly. Most micrometers come with a precision dowel which allows for easy and accurate adjustments.