MICROMETER INFORMATION


Each number on the sleeve of the micrometer represents 0.100 (one hundred one-thousandths, or 1/10) of an inch.

When reading it, shorten the "one-thousandths" to just "thousandths."

Each of the four equal spaces between each number on the sleeve represents 0.025 (twenty-five thousandths. or 1/4 of 0.100) of an inch. One revolution of the thimble changes the reading one space (0.025") on the sleeve's scale.







The beveled edge of the thimble is divided into 25 equal parts. Each space represents 0.001 (one thousandth, or 1/1000) of an inch.

The step-by-step process of taking a micrometer reading involves adding the three separate readings.



Example:

1. Read the largest number on the sleeve that has been uncovered by the thimble - it is 3. So, your first reading is 0.300" (three hundred thousandths):

      0.300"

2. Count the number of graduations past the 3 that the thimble has uncovered - there are 2 graduations.

Since each represents 0.025",  2 x 0.025" = 0.050" (fifty thousandths) is our second reading. Add it to the first reading:

      0.300" + 0.050"

3. The graduations on the thimble show that it has revolved 12 spaces beyond its 0 mark. 0.012" (twelve thousandths) is the third reading we must add:

    0.300" - 1st reading
    0.050" - 2nd reading
    0.012" - 3rd reading
    ------
    0.362" - total (three hundred, sixty-two thousandths of an inch)

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