Explained: Least Count of Screw Gauge Formula With Example

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[{"selector":"#anim-670cd798-aa63-4442-8aea-9821b008ae6d","keyframes":{"opacity":[0,1]},"delay":0,"duration":1300,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-7868fd8c-86b3-4a74-8d0f-4ee1513363ab","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":1300,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Below is the labelled image of a screw gauge that shows how it looks like in real life.

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LC = (pitch of the screw) ÷ (number of divisions of the circular scale)

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The circular scale reading is the reading that matches the line on the pitch scale. Let us see the example of finding the diameter of an object.

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Firstly, clean the spindle and anvil to get the most accurate results. Now, place the object in between the spindle and anvil.

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The ratchet counter has to be rotated clockwise to tighten the sheet such that it should not move while taking the measurements.

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Suppose the screw covered a distance of 1 cm by doing 20 rotations to tighten the object. Then, pitch of the screw gauge = 1/20 = 0.05 cm or 0.5 mm

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Usually, the number of divisions on the circular scale will be given on the instrument. Say, the last reading on the circular scale is 200. Then, The least count of screw gauge (LC) = 0.5 ÷ 200 = 0.0025 mm

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This is how you calculate the LC of the screw gauge. You need to continue this process and find the diameter of the given object by finding the main scale reading and zero correction.

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Hope this clarifies your doubt on how to find the least count of a screw gauge. How about sharing these with your classmates?

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