Question

What is Least Count of Screw Gauge?

Answer 1

1. A screw gauge is a device that runs in the screw theory.
2. By spinning the screw handle, we can cause the main scale to rotate linearly.
3. This linear flow is used to determine the wire diameter or thickness of the metal layer.
   
4. When the anvil and spindle ends are brought into contact, the zero mark of the circular scale frequently does not correspond to the baseline of the main scale due to mechanical defects.
5. The screw gauge and the vernier caliper are fundamentally different in that the screw gauge is exclusively used for external measurements, whilst the vernier caliper is utilized for internal measurements.
6. It is an instrument that is used for measuring the diameter of thin wires, and the thickness of small sheets such as glass or plastics.
7. The pitch of the screw gauge is defined as the distance moved by the spindle per revolution which is measured by moving the head scale over the pitch scale in order to complete one full rotation.
8. Mathematical expression for the least count of screw gauge:
   $\mathrm{least}\mathrm{count}\mathrm{of}\mathrm{screw}\mathrm{guage}=\frac{\mathrm{pitch}\mathrm{of}\mathrm{screw}\mathrm{gauge}}{\mathrm{total}\mathrm{number}\mathrm{of}\mathrm{divisions}\mathrm{of}\mathrm{circular}\mathrm{scale}}$
   $\mathrm{Leat}\mathrm{count}\mathrm{of}\mathrm{screw}\mathrm{gauge}=\frac{1\mathrm{mm}}{100}=0.01\mathrm{mm}$

Hence, the least count of screw gauges is 0.01mm.