How to Read a Metric Micrometer
Now let’s put all of this together and try to figure out what the micrometer below is reading.
First the barrel scale: count over from the 10…11… and 12. So it’s 12 mm plus something. The “something” comes from the thimble scale. Remember we will read the thimble scale as two decimal places. So starting with the thirty (printed on the thimble) we count up to 33 before we get to the horizontal line we are reading from. So the barrel reads 12 mm and the thimble reads 0.33 mm. It may be a good idea to write down what each scale is reading and then add them together like this…
This is pretty obvious for this reading, but it will help explain the next concept.