Horizontal Rotary Hook. The hemmer foot, sometimes referred to as the rolled hemmer, is used to stitch the narrow rolled hems usually found on shirt tails, table linens, and along the edges of frills. The hemmer is designed with a scroll shaped feed on top and a straight groove on the underside which determines the width of the finished hem. The 4 mm / 6 mm set will allow for the use of heavier fabrics. The Hemmer Foot creates straight, professional rolled hems on lightweight fabrics.