Ultrasonic machining (USM) has been considered as a new cutting technology that does not rely on the conductance of the workpiece. USM presents no heating or electrochemical effects, with low surface damage and small residual stresses on workpiece material, such as glass, ceramics, and others; therefore, it is used to drill microholes in brittle materials. However, this process is very slow and tool wear dependent, so the entire process has low efficiency. Therefore, to increase microhole drilling productivity or hole quality, rotary ultrasonic machining (RUM) is considered as a strong alternative to USM. RUM, which presents ultrasonic axial vibration with tool rotation, is an effective solution for improving cutting speed, precision, tool wear, and other machining responses beyond those of the USM. This study aims to reduce the microchipping or cracking at the exit of the hole, which inevitably occurs when brittle materials are drilled, with consideration of tool wear. To this end, response surface analysis and desirability functions are used for experimental optimization. The experimental results showed that the proposed RUM scheme is suitable for microhole drilling.