A relatively simple and rapid method for preparing high‐quality electron microscope disk specimens from electrically conductive and nonconductive brittle bulk materials is described. The technique utilizes a model 2–334 Raytheon ultrasonic impact grinder to generate and transmit high frequency vibrational energy through a tube‐shaped tool tip to an abrasive‐water slurry circulated over the bulk material. Machining is accomplished by the abrasive particles resonating and impacting the bulk material in a vertical plane below the tool tip. The net effect produces a microscopic grinding action on the workpiece that parallels the contour of the end of the tool tip.