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Reading the Micrometer. Objectives. Identify micrometer parts Determine micrometer reading. sleeve. thimble. anvil. spindle. frame. This is a English micrometer. Know the names of the different parts of the Micrometer.
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Objectives • Identify micrometer parts • Determine micrometer reading
sleeve thimble anvil spindle frame This is a English micrometer
The sleeve goes from 0 to 0. The last 0 could have a 10 there. It represents a movement of 1 inch (1.000) Each large number is equal to .100. 1= .100, 2= .200, 5= .500 etc. The Lines in between the numbers represent .025 thousands of and you would count them up .025, .050, .075, .100
The Thimble on the side of the sleeve moves as you rotate it. Each mark is = to .001. Each time it moves one full turn it travels a distance of .025.
To read you must take each section and add it together for example, The last large Number is 5 so we have .500 we have one line past the 5 so we have .025 and the thimble is turned to the 7 so we have .007 add it together and we have .532
The last large Number is 2 so we have .200 we have three lines past the 2 so we have .075 and the thimble is turned to the 18 so we have .018 add it together and we have .293
Some times the thimble is part way in between the two numbers. Now you will have to carry it out to a 4th digit that is ten thousands of an inch. Write down the answer to this problem add a .0005 to it because it is halfway in between the 12 and 13. Answer at the end of the show.
3 0 1 2 3 4 5 6 7 8 9 2 1 0 24 22 For clarity we will use an animated figure. 23
Let’s take a close look at the sleeve of the micrometer.
One inch (1.000) 25/1000 inch (0.025) 3 0 1 2 3 4 5 6 7 8 9 0 0 1 2 3 4 5 6 7 8 9 0 2 1 0 24 23 22 1/1000 inch (0.001) 1/10 inch (0.100)
Smallest Measurement Largest sleeve reading 0 1 2 3 4 5 6 7 8 9 15 18 0 1 2 3 17 0.341 inches One mark past largest sleeve reading 16 15 14 13 Thimble Reading Now, an example... 19 18 17 16 0.000 15 14 13 0.300 0.025 0.016
Smallest Measurement Largest sleeve reading 0 0 1 2 3 4 24 23 22 21 3.496 inches 20 19 18 17 16 Thimble Reading Three marks past largest sleeve reading Another example... 20 15 3.000 0.400 0.075 0.021
Review... • Lightly tighten on object. • Determine smallest measurement when micrometer is closed. • Find largest visible number on sleeve and multiply times 0.100.
Review... • Count number of marks past largest visible number on sleeve and multiply times 0.025. • Multiply thimble reading times 0.001. • Add all numbers to get answer.