Linear displacement by flexure, spring or ??? I'm doing a little project of mine and I have encountered a problem.. The project is basically a motion platform that moves in three directions at very low forces (few mN). I got the first two direction done (X,Y), but the third is giving me trouble due to the gravitational force. Basically I use some very thin metal sheets (flexures) that allow deflection in one direction and none in all others. In X and Y I have no issues with gravity, but in the Z direction the beams own weight and as the force is not applied directly at the centre of the flexures, my whole thing starts to rotate which I don't want. In this image you can see how X and Y sort of look like; you can imagine Z has a problem with it's own weight. http://www.precisionballs.com/images/flexure_fig21.jpg So I was thinking of maybe using a linear spring that is very stiff in the other directions, or maybe a different method. Do such springs exist at such a stiffness (20 N/m)? Maybe other options? It is at milimeter/few centimeter scale. I can elaborate on the design if necessary!