An atomic force microscope (AFM) has been used to study solvation forces at the solid-liquid interface between,highly oriented pyrolytic graphite (HOPG) and the liquids octamethylcyclotetrasiloxane (OMCTS), n-hexadecane (n-C16H34), and n-dodecanol (n-C11H23CH2OH). Oscillatory solvation forces (F) are observed for various measured tip radii (R-tip = 15-100 nm). It is found that the normalized force data, F/R-tip, differ between AFM tips with a clear trend of decreasing F/R-tip with increasing R-tip.