Vernier height gages are used to mark out lines when accuracy is particular importan and widely used on surface plates and on machine tables. The height gage with an indicator attachment is used for checking locations of surface and holes. The height gage with a scribe attachment is used to mark reference lines, locations, and stock allowances on castings and forgings.
Vernier height gauges have a large steel base for stability and a hardened steel column engraved with inch and mm units. The moving slide is engraved with vernier calibrations enabling setting to an accuracy of 0.02 mm and 0.001�? Attached to the moving slide is a wedge-shaped steel scribe that has a pointed tungsten carbide tip. The height of the scribe’s point can be finely adjusted with a thumbscrew.
The method of setting and reading a vernier height gauge is the same as for other vernier instruments. The work to be marked out with a vernier height gauge must be set vertically on a surface plate, using an angle plate.The height of the scribe is set with the moving slide’s fine adjusting screw. The marking out lines are then scribe onto the work’s surface by steadily moving the vernier height gauge along the surface plate (following the same procedure as for using a surface gauge).On some vernier height gauges, the height of the main scale can also be finely adjusted. This enables measurements to start from a convenient reading, which is useful if the shape of the workpiece is such that it needs to be mounted on a parallel strip .Note that digital height gauges are now becoming more common as they are much quicker to set up and more accurate to set.
Precision vernier height gauges must be stored in their original packaging case and should be carefully used and maintained. If you suspect that the instrument is inaccurate, it must be reported to your fault, so a ‘back footed�?approach could prove to be appropriate.