Figure 3. Quantification of Post stiffness.

Post stiffness was determined optically, using a camera to track post displacement under the influence of differing weights and magnet separation distances. (A) An image showing the optical method for obtaining post stiffness. (B) Increasing the magnitude of the weight attached to the end of the post resulted in a linear increase in post bending, independent of the magnet separation distance. (C) The relationship between magnet plate distance x and post resistance k is given by the inverse exponential equation: k = 12.69e ^−0.138x +0.91. The vertical line indicates the closest possible distance between the bottom of the magnet post and magnet plate (5.5 mm).