Patent ID: 7626383

Claim:
An apparatus for examining an object having a first surface, wherein the object includes a structure that penetrates the first surface, and wherein the structure includes a circular boundary, the apparatus comprising: a rotatable magnetic-eddy-current probe that includes an excitation unit that generates an alternating magnetic excitation signal, wherein the rotatable probe has an axis of rotation, wherein the probe, when placed adjacent the first surface of the object, is configured to detect interaction of the alternating magnetic excitation signal with the object, and wherein the apparatus is configured to constrain side-to-side movement of the axis of rotation while the probe is rotated around the axis of rotation such that at least a portion of the probe moves along the first surface of the object substantially concentric to the circular boundary of the structure, wherein the structure includes a fastener that has a head, wherein the head of the fastener includes a dimple aligned with the center axis of the fastener, and wherein the probe includes a sharp protrusion that has a size and shape to fit into the dimple in the fastener to provide a pivot point and constrain side-to-side movement of the axis of rotation while the probe is rotated.