a milling machine removes metal by rotating a multi-toothed cutter that is fed into the moving workpiece. the spindle can be fed up and down with a quill feed lever on the head. the bed can also by fed in the x, y, and z axes manually. once an axis is located at a desired position and will no longer be fed, it should be locked into position with the gibb locks. most milling,introduction to the milling machine start me,portland state university me 120introduction to the milling machine milling machine operation of the digital readout (dro) the z-direction readout on the dro is used to tell you how deep you are drilling. the x- and y-direction readouts can help you accurately position the holes in the faceplate and the pump exit hole.