Difference Between Vernier Caliper and Micrometer Screw Gauge

Accurate measurements hold great importance in the field of physics. Measurements tools like Vernier caliper and micrometer screw gauge are commonly used by physicists in their experiments. Since their functions are similar, there is always a chance of intermingling them. However, there are very basic differences among Vernier calipers and micrometer screw gauge that cannot be ignored. These differences need to be understood for a firm base in physics measurements because the two tools have very important uses when it comes to the measurement of physical objects.

The foremost difference between the two tools is their least count i.e. the smallest unit they can measure. The least count for the most sensitive vernier caliper is 0.05 mm while that for micrometer screw gauge is 0.01mm. This shows that the screw gauge can be used for measuring smaller units that the Vernier can read. Therefore it is preferred for more sensitive readings.

The difference also lies in their shape. Vernier caliper has an elongated scale with a slider. It has a Vernier scale and a main scale. The jaws of the caliper are fixed around the object and the readings on the two scales are taken for one final answer. Screw gauge has a rotary handle and has two measurements known as the sleeve and the thimble readings. The screw gauge has a spindle and anvil which hold the object between them for measurements.

Due to the differences in their structure, these two tools also differ in their purpose. Although both of them are used to measure length, the type of it differs. The Vernier caliper measures the inner diameter, outer diameter and the depth of an object accurately. It can also take several measurements at the same time. However, due to its auxiliary shape, the screw gauge is used for measuring only diameters. Therefore its use is limited.


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    Vernier calipers:

    If you have two opposite sides of an object and want to measure their distance then using Vernier calipers is the best way. They can be used for measuring inner and outer diameters and the depth of an object. They have a least count of 0.05mm. However, the accuracy varies according to the type of caliper used. The two main types of calipers used for measurement are dial calipers and digital calipers.

    - Image courtesy: blog.makezine.com

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    Micrometer screw gauge:

    The micrometer screw gauge is used for measuring the diameters of round objects. It has a least count of 0.01 mm.

    - Image courtesy: tutorvista.com

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