Pancake or Flat Coils also called Archimedes Coils*
These recently introduced coils make the inspection of disc shaped parts such as brake and clutch discs quick and easy.
Flat coils are available in 12", 18" and 24" diameters (larger diameters on special order).
Clamp the coil between the head and tailstock of your wet horizontal tester. Lay our test piece on the flat coil and test. Flip the part over and apply a second shot.
* widely used in Europe and specified by such companies as Bendix and Rolls Royce