Question

What is the formula for pitch and least count of a screw gauge?

Answer 1

Hint:A screw gauge is an instrument that is used to measure the radius, diameter or thickness of an object having cylindrical or spherical shape accurately. It has upper head, lower head, anvil, spindle, barrel etc.

Complete step by step solution:
A screw gauge measures by what amount the screw is rotated and then it is used to convert smaller distances into larger distances with great precision. It mainly depends on two main parameters: pitch and least count.

Pitch of A Screw Gauge: It is defined as the distance moved by the spindle in one unit of revolution. For one complete rotation, the head scale of the screw gauge is to be moved over the pitch scale. Mathematically, the formula for pitch of a screw gauge is given by
$$\text{Pitch}={\displaystyle \frac{\text{Distance}}{\text{No. of rotations}}}$$

Least Count Of A Screw Gauge: The distance moved by the tip of the screw gauge when head scale is turned through one division. Least count of screw gauge is taken as 0.0001 cm. Mathematically, the formula of least count of a screw gauge is written as
$$L.C={\displaystyle \frac{\text{Pitch}}{\text{No. of divisions}}}$$

Note: In a screw gauge a U-shaped metal frame is attached to an end of the frame. Also a scale which is in millimetres is attached parallel with the cylinder. This scale is also known as pitch scale. The screw gauge is also like a vernier calliper, but they have different functions. It can only be used for making external measurements. On the other hand, a vernier calliper can be used to make internal as well as external measurements precisely.