How to Read a Micrometer

Reading a micrometer takes practice.

To learn to read the mike you need to understand the Thimble and the Sleeve.

Here we are going to learn to read the micrometer by figuring out the markings on the Thimble and the Sleeve.

The Sleeve does not move.   It looks like a ruler with ten numbers.   The space between each number is divided into quarters.   As the Thimble rotates around this Sleeve it covers up, or reveals the numbers marked on the Sleeve.

It is easy to read a micrometer if you think of the markings on the Sleeve as dollars and quarters.

Now it gets a little easier to read the mike.   For example, what are the readings on the micrometers shown below?   (click on the arrow at the end of "What is this reading" to get the answer)

What is this reading?

2 dollars

or

.200 - "point two-zero-zero"

What is this reading?

2 dollars 25 cents

or

.225 - "point two-two-five"

What is this reading?

2 dollars 50 cents

or

.250 - "point two-five-zero"

What is this reading?

2 dollars 75 cents

or

.275 - "point two-seven-five"

What is this reading?

3 dollars

or

.300 - "point three-zero-zero"

What is this reading?

3 dollars 75 cents

or

.375 - "point three-seven-five"

If you think of the lines on the Sleeve as dollars and quarters,
the lines on the Thimble represent "pennies" or cents.

As the thimble rotates, you add those pennies to the dollars and quarters

O.K. so now we know how to read a micrometer!   We just need some practice.   In the picture below, the Sleeve shows 3 dollars and one quarter (25 cents).   The Thimble shows one penny.   To calculate this reading we add 3 dollars plus 1 quarter plus 1 penny. The actual measurement is .326 inches.

What is this reading?

3 dollars 1 quarter

plus 1 penny

equals

3 dollars 26 cents or .326"

See if you can calculate the measurement below

What is this reading?

3 dollars 3 quarters

plus 10 pennies

equals

3 dollars 85 cents or .385"

Reading a micrometer gets easier with practice.
Here are some practice pages.

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Last modified:Tuesday, September 07, 2004 16:50:34