Force diagram to mount lenses in a fully monolithic mount with clamping springs. We sketch our approach in a plane only, but in the full three-dimensional case these structures are preferably arranged with an azimuthal distance of 120. The axial preload F _preload presses the lens against the mechanical reference (grey), which aligns the lens axially and induces the friction forces R _pos.l and R _pos.r , here marked as their line of action. To precisely align the lens, the friction has to be overcome by the radial force difference between F _rad.l and F _rad.r .