To create a bound buttonhole with a contrast or matching welt edge, cut a bias or cross grain strip of fabric approx. 2 3/8" (6 cm) wide and 1 5/8" (4 cm) longer than the finished buttonhole opening. Apply interfacing to the back of strip. Transfer all pattern markings to the buttonhole area and fabric strip. With right sides together, centre interfaced strip over marked buttonhole area and pin or baste in place. Shorten the stitch length slightly. Stitch along the marked side, top and bottom buttonhole lines. Cut along the centre of the buttonhole area, ending approx. 1/4" (7 mm) from ends. Clip into corners. Turn facing strip to the inside of the garment. Press seam allowances towards centre of buttonhole. Fold facing strip so top and bottom edges meet in centre of buttonhole opening. Press in place. To make sure welt stays evenly in place prior to top stitching, baste the centre edges together. From the right side, stitch-in-the-ditch around the buttonhole opening to secure the facing stripin place. With the garment right side up, fold back the garment to expose the small triangular fabric piece and the end of the welt strip. Stitch across the triangular section to secure it to the welt piece. Remove basting threads.