A sewing device for producing piped openings such as pocket slashes, with or without a pocket flap. The sewing device includes a two-needle sewing machine having a vertically moveable center knife for cutting an opening to be piped, a cutting device including two vertically moveable angle cutting knives for performing gusset cuts, and a material transport device for receiving material to be sewn and transporting such material between the sewing machine and the cutting device. Also provided is a control system including a microprocessor for adjusting the operating positions of the various components to move the points of commencement of the parallel seams, the center knife, and the angle cutting knives, individually or jointly, forward or backward, to conveniently and selectively change these sewing parameters in response to the specific workpiece. In one embodiment, a common drive motor is provided for the two-needle sewing machine, the transport device, and the cutting device. Alternatively, the mechanism is substantially simplified in a sewing device wherein the two-needle sewing machine is driven by a first electric motor, and the transport device and the cutting device are driven by at least one additional electric motor.