The needle of system B-27 has a small ball point for working knit fabrics, without damaging the stitches. It is used in industrial overlock, coverstitch and safety-stitch machines for elastic knit fabrics. Suitable machine classes are found, among others, at Siruba (classes 401, 504, 505F1-04, 512 bis 514), Kingtex (classes SH, SHF, SK, SH-7002-032-M02) and Yamato (classes 74 Series, 78 Series, AEF, AFZ).
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.
