The 5640 SES needle (needle system 5640) has a small ball point for working knit fabrics, without damaging the loops. It is used in industrial chainstitch and general-purpose sewing machines for everyday garment and textile manufacturing. Suitable machine classes are found, among others, at Kansai (classes BX-1425P, BX-1425PS, BX-1425PS-ET, BX-1425PSSM), Pfaff (classes 3538, 3548, 3552, 3816) and Renown (classes CTN, D, DTN, DTR).
Thinner needle sizes are used, among others, for fine, light jersey and tricot fabrics, and the thicker versions for heavy, dense knit fabrics and technical knits. As sewing thread, a matching thickness is usually recommended depending on the needle size chosen, e.g. from Amann Serafil or Rasant; for very stretchy seams, a texturised thread also works well. The ball point glides between the loops instead of piercing them, keeping the seam clean and undamaged.
