An apparatus for machining metal workpieces has a frame defining machining, pick-up, and drop-off stations. A vertical slide is vertically shiftable on the machine frame. In turn a horizontal slide carrying a rotatably driven holder is horizontally shiftable on the vertical slide between respective pick-up, machining, and drop-off positions above the stations. A holder is provided in the machining station, and one of the holders is adapted to hold a tool and the other of the holders for holding a workpiece for machining the workpiece in the machining station. A pair of shields is fixed to the vertical slide and horizontally flanks the machining station. One of the shields is between the machining station and the pick-up station. Respective slidable doors on each of the shields are shiftable between a closed position blocking movement of the rotatable holder past the respective shield and an open position permitting such movement.