Abstract: A suspension system for rigidly mounting an object such as a microwave cavity on a support surface subject to limited expansion and contraction. The object is secured in place by three or more support legs radially spaced from a central reference point and angularly spaced from each other, each leg being specially configured to permit limited radial movement of the underlying surface relative to the object, but to resist relative movement in all other directions. The forces applied to the mounted object, therefore, remain fixed regardless of expansion or contraction of the underlying support surface.