Micrometer Screw Gauge
An ultra-precise measuring tool that uses a calibrated screw thread mechanism to measure microscopic thicknesses or diameters.
Governing formula
Reading = Main Scale + (Circular Scale Division × Least Count)
SI unit
mm
In depth
Based on the principle that turning a calibrated screw by one full rotation moves the spindle forward by the pitch distance (typically 0.5 mm). Dividing the thimble into 50 divisions yields a least count of 0.01 mm (10 µm).
Examples in the real world
Measuring the thickness of a glass slide or the gauge diameter of thin copper wire.