The problem of symmetrically loaded circular plates of constant thickness is covered adequately in several of the standard textbooks on the strength of materials. Formulae are derived enabling the deflections and stresses to be readily calculated in any portion of the plate. The problem is complicated by the introduction of a variable thickness and by a variation of material properties due to a temperature gradient down the radius of the plate; conditions such as are encountered in gas turbine wheels, bearing support diaphragms and flexible disc couplings. Methods exist whereby the plate can be solved if the thickness is a simple function of the plate radius, but in practice this is not always so, the profile often being complicated by flanges and spigots.