A process and machine tool for machining workpieces with two parallel work spindles fitted on a headstock. The distance between the work spindles is altered with the aid of a driven adjuster. The machine tool for machining workpieces, especially for numerically controlled machining centers, has two work spindles (1, 2) fitted parallel to each other on a headstock (3), where at least one work spindle (2) can be adjusted perpendicularly to its axis.