Abstract: Workpieces are machined in an apparatus having a central grinding station, first and second finishing stations and first and second spindles movable. First one of the workpieces is ground in a coarse-grinding station with the first spindle while rotating and finishing another of the workpieces with the second spindle in the second finishing station and then, while continuing to rotate and coarse grind the one workpiece in the coarse-grinding station, switching the other finished workpiece for an unmachined workpiece with the second spindle. Then the unmachined workpiece is ground in the coarse-grinding station with the second spindle while rotating and finishing the coarse-ground workpiece with the first spindle in the first finishing station and then, while continuing to rotate and coarse grind the unmachined workpiece in the coarse-grinding station, switching the finished workpiece for an unmachined workpiece with the first spindle.

Abstract: A machining apparatus has a vertical support frame defining two machining stations spaced apart in a direction, holders in the stations for rotating respective workpieces each about a respective station axis, and a transfer device for loading rough workpieces into the holders and for taking finished workpieces out of the holders. A single machining tool can be shifted in the direction between one position engaging the workpiece in one of the stations and out of engagement with the workpiece in the other of the stations and another position engaging the workpiece in the other station and out of engagement with the workpiece in the one station.

Abstract: A machining apparatus has a vertical support frame defining two machining stations spaced apart in a direction, holders in the stations for rotating respective workpieces each about a respective station axis, and a transfer device for loading rough workpieces into the holders and for taking finished workpieces out of the holders. A single machining tool can be shifted in the direction between one position engaging the workpiece in one of the stations and out of engagement with the workpiece in the other of the stations and another position engaging the workpiece in the other station and out of engagement with the workpiece in the one station.