Abstract: An overedge sewing machine having a reciprocating trimmer knife is used to sew elastic tape to a fabric. The elastic tape is fed through a tape guide which is movable from a rest position in which it guides the tape toward the stitch-forming mechanism of the sewing machine in the direction of material movement, to a second position in which it guides the tape to a position to be cut off by the trimmer knife. The tape guide includes a controllable tension which is located close to the stitch-forming mechanism when the tape guide is in its rest position to effect instant control of gathering. The tape guide is controlled by a knee shift which is movable from a rest position, through a "gathering" position, to a "cut-off" position. A stop mechanism requires the application of significant additional pressure on the knee shift to move it from the "gathering" position to the "cut-off" position.