For example, an oval-shaped part rotating on an elliptical path can appear to be round. New equipment will usually include a computer-aided routine that guides an operator through the alignment process. Proper gage head needed The inductive gage head is a simple electromechanical device that measures in two directions. Think of it as an electronic test indicator that detects bumps and depressions on the workpiece. A processing unit records the amplitude and frequency of those undulations and converts the data into information about the roundness, shape, or form of the workpiece.
Most manufacturers offer more than one type of gage head.
Be sure to select one that can handle your application. If the workpiece has interrupted surfaces, consider adjustable pre-travel to avoid damaging the probe tip or gage head. For circular measurements, the gage head is normally held stationary while the part is rotated. Typically a vertical column with a horizontal arm is used to hold the gage head and to provide a means of adjustment to suit different workpiece heights and diameters. On roundness machines the vertical and horizontal axes are for positioning only.