Abstract: A machine tool controller, for automatically controlling the Z axis operations of a machine tool, along a direction parallel with the axis of a tool-holding spindle, includes a system for executing programs in accordance with data which is manually entered into the system for each of a plurality of individual machining operations. The data, representative of two distances, respectively above and below the surface of the work to be machined, feed speed during machining and spindle rotating speed, may be manually entered through the keyboard of a control panel, or the two distances may be entered directly from a position counter which monitors the Z axis position of the spindle, and successful data entry is verified by indicator lights. All of the data for a single machining operation is stored in a memory unit, associated with the microprocessor system, at a single storage location, with each separate item of data stored in a specified memory location of the storage location.