Eddy current probes are used in non-destructive testing of metals. It basically is a small pick-up coil excited by an ac current and produces an alternating magnetic field. When the probe tip is placed on the metal surface the eddy currents generated in the metal change the properties of the pick-up coil. These changes can be used to find out e.g. the presence of cracks in the metal or can be used to measure the thicknes of paint layers on the metal. (see e.g. https://en.wikipedia.org/wiki/Eddy_current). The effect is also used in inductive proximity probes in e.g. 3D printers. In my application I scan the probe by a motorized stage and move it until it slightly touches the metal surface. The probe holder reduces the force on the surface when the probe is touching by using the bending of the thing plastic spring holding the probe. At the moment the actual force on the surface is not measured. This could be added by including a strain gauge on the spring. To be done later ... The holder is printed in one piece without support with the thin spring part pointing upwards, I printed the holder using PLA with a 0.2 layer height without support on a simple da Vinci Jr. 3D printer. The spring blade is 2 layers thick. The four holes in the top plate are used to mount the holder to the extruder head of an old 3D printer. The enclosed FreeCAD script file can be used to adapt the design.