A dial gauge-like length measuring instrument with a an angular movable sensor for small length difference measurement is called lever gauge.
Due to its design, it is very well suited for concentrically tests on lathes since the measuring pin cannot tilt. The flat design allows measurements in tight spaces.
With lever gauges it is always possible to measure in two directions.
This allows easy reading of the measured values with analogue devices, using the opposite line scale.
The correct measured value is obtained directly when the lever is parallel to the measuring surface. If the angle is too large, the measured value can be corrected by calculation.
The measuring range is usually between 0.01 and 0.5 mm and the deviations correspond to those of a dial gauge.
The measuring ball on the sensor is usually made of low-wear materials such as carbide or ruby.