Micrometer Scales

Reading a Micrometer

Micrometer Reading

Interpolating a Micrometer Reading

The closeup in figure 3-37 will help you understand how to take a complete micrometer reading. Count the units on the thimble scale and add them to the reading on the sleeve scale. The reading in the figure shows a sleeve reading of 0.250" (the thimble having stopped slightly more than halfway between 2 and 3 on the sleeve) with the 10th line on the thimble scale coinciding with the horizontal sleeve line. Number 10 on this scale means that the spindle has moved away from the anvil an additional 10 x 0.001M or 0.010". Add this amount to the 0.250" sleeve reading, and the total distance is 0.260". Read each of the micrometer settings in figure 3-38 so that you can be sure of yourself when you begin to use this tool on the job. The correct readings are given following the figure so that you can check yourself.

Figure 3-39 shows a reading in which the horizontal line falls between two graduations on the thimble scale and is closer to the 15 graduation than it is to the 14. To read this to THREE decimal places, refer to figure 3-39 and calculation A. To read it to FOUR decimal places, estimate the number of tenths of the distance between thimble-scale graduations the horizontal line has fallen. Each tenth of this distance equals one ten-thousandth (0.0001) of an inch. Add the ten-thousandths to the reading as shown in the calculations of figure 3-39B.

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Home > Measuring Tools > Micrometers > Reading a Micrometer Caliper

July 28, 2014