The needle of system 251 EU has an eccentric round point (tip above the eye) for working woven and knit fabrics. This is a curved needle: it penetrates only the surface of the material and stays invisible on the right side of the fabric – the standard design for overlock, blind-stitch and linking (kettling) machines. It is used in industrial chain-stitch special-purpose machines with a curved needle, among others for overlock, blind-stitch and linking (kettling) work. Suitable machine classes are found, among others, at Maier (classes 120 to 121, 211, 220, 221), Global (classes BM 221, BM 252, BM 352, BM 221 ALL CLASSES) and Pfaff (classes 8103, 231, 8103 ALL CLASSES).
Thinner needle sizes are used, among others, for light, fine woven and knit fabrics such as blouse and shirt fabrics, and the thicker versions for heavy, multi-layer woven and knit fabrics as well as technical textiles. As sewing thread, a matching thickness is usually recommended depending on the needle size chosen, e.g. from Amann Serafil (polyester) or Rasant (polyester/cotton).
