A heated atomic force microscope cantilever can raise the temperature of a substrate at the tip-substrate contact to over 500 °C while not substantially raising the temperature of the nearby substrate not in contact with the tip. Models based on continuum solid contact and sub-continuum heat conduction in the tip and in the sample predict that the hot spot could be as small as 2 nm in diameter. This approach to nanoscale thermal processing could be used for fundamental studies of temperature-dependant reactions using small numbers of molecules or atomic clusters, or applications in thermomechanical manufacturing. The resolution limits of nanoscale thermal processing in time, space, and temperature, depend upon the cantilever design, the tip-sample contact, and the substrate material. This paper explores solid contact and thermal conduction between a heated silicon cantilever tip and three different substrates: silicon, a thick metal film, and a thick amorphous layer.