Spinning probe-type eddy current instruments are most useful in the detection of:

Spinning probe-type eddy current instruments excel in the detection of very small surface blemishes due to their design and operational capabilities. These instruments feature a rotating probe that enhances their sensitivity and resolution, making them particularly adept at identifying minute surface imperfections. The spinning motion allows the probe to cover a larger area efficiently while maintaining a high sensitivity to small changes in the material's electrical conductivity, which assists in detecting such blemishes.

While these instruments can provide some information regarding subsurface inclusions and internal conditions, their primary design focus is to locate defects that are very close to the surface of the material. Therefore, their capabilities are most pronounced when assessing surface quality, particularly small blemishes that might not be detectable by other NDE methods.