Question

How to find the readings of a screw guage?

Answer 1

uide on how to read a micrometer screw gauge. Similar to the way a vernier caliper is read, a micrometer reading contains two parts:

the first part is contributed by the main scale on the sleevethe second part is contributed by the rotating vernier scale on the thimbleA typical micrometer screw gauge

The above image shows a typical micrometer screw gauge and how to read it. Steps:

To obtain the first part of the measurement: Look at the image above, you will see a number 5 to the immediate left of the thimble. This means 5.0 mm. Notice that there is an extra line below the datum line, this represents an additional 0.5 mm. So the first part of the measurement is 5.0+0.5=5.5 mm.To obtain the second part of the measurement: Look at the image above, the number 28 on the rotating vernier scale coincides with the datum line on the sleeve. Hence, 0.28 mm is the second part of the measurement.

You just have to add the first part and second part of the measurement to obtain the micrometer reading: 5.5+0.28=5.78 mm.

 

To ensure that you understand the steps above, here’s one more example: