An apparatus for a thermal actuator for a micromechanical device, especially a liquid drop emitter such as an ink jet printhead, is disclosed. The disclosed thermal actuator comprises a base element and a cantilevered element including a thermo-mechanical bending portion extending from the base element and a free end portion residing in a first position. The thermo-mechanical bending portion has a base end width, wb, adjacent the base element and a free end width, wf, adjacent the free end portion wherein the base end width is substantially greater than the free end width. The thermal actuator further comprises apparatus adapted to apply a heat pulse directly to the thermo-mechanical bending portion causing the deflection of the free end portion of the cantilevered element to a second position. The width of the thermo-mechanical bending portion may reduce substantially quadratically or in an inverse power fashion as a function of the distance away from the base element or in at least one step reduction. The apparatus adapted to apply a heat pulse may comprise a thin film resistor. Alternatively, the thermo-mechanical bending portion may comprise a layer of electrically resistive material having a heater resistor formed therein to which is applied an electrical pulse to cause rapid deflection of the free end portion and ejection of a liquid drop.