Rotating concave eddy current probe

A rotating concave eddy current probe, comprising:

• a probe body comprising a right circular-cylinder made of a non-conducting material;
• the body having a central axis, an upper surface, a bottom surface, and a cylindrically-shaped side surface;
• a concave dimple recessed into the bottom surface of the probe body, centered on the cylinder's central axis, and having an axisymmetric inner surface that conforms closely to the shape of a head of a raised head fastener;
• a magnetic test coil embedded within the probe body;
• comprising a right circular-cylinder with a lower end, an upper end, and a central axis;
• a pair of electrical leads embedded inside the body, for supplying electrical current to the coil through the coil's upper end;
• and
• electrical connection means disposed on the exterior of the probe body, and connected to the pair of embedded electrical leads, for connecting the magnetic test coil with a source of electrical current;
• wherein the lower end of the test coil is located flush with the inner surface of the concave dimple;
• wherein the central axis of the test coil is aligned to intersect the central axis of the probe body;
• and
• wherein the central axis of the test coil is oriented at an inclined angle, α, relative to the probe body's central axis, that aligns the test coil's axis to be perpendicular to the concave surface of the recessed dimple.