The height Vernier caliper, more commonly called a height gauge, is designed to measure vertical heights from a flat reference surface — typically a precision surface plate. Instead of being held in the hand like other calipers, the height gauge has a heavy, precision-ground base that sits on the surface plate, ensuring the instrument is perfectly vertical.
A vertical beam rises from the base, along which a sliding carriage moves. The carriage carries either a scriber (for scribing layout lines on workpieces) or a contact point (for measurement), and the height of the contact point above the surface plate is read from the Vernier, dial, or digital scale on the beam.
Height gauges are fundamental layout and inspection tools in toolrooms, inspection departments, and machine shops. For layout work, the scriber attachment is used to mark precise horizontal lines at specific heights on workpieces, which guide subsequent machining operations.
For measurement, the contact point is brought into contact with a feature of the workpiece (which is also sitting on the surface plate), and the height reading gives the absolute height of that feature above the surface plate. By making multiple height measurements — to the top and bottom of a feature, for example — step heights, shoulder heights, and total component heights can be determined with precision.
Modern digital height gauges represent a significant advancement over traditional Vernier height gauges. They often include features like automatic height differentiation (the gauge calculates the difference between two height readings automatically), min/max capture (the gauge records the highest and lowest point touched during a sweep, useful for finding the highest point on a curved surface), and data output for SPC systems.
Some advanced height gauges include a motorized fine-feed mechanism for slow, controlled lowering of the contact point onto a surface, which reduces measurement errors caused by contact force variation. Height gauges are available from small bench-top versions with 150mm range to large floor-standing models with 1000mm or more of measurement range for large workpiece inspection.