The 135X17 SD1 needle (needle system 135X17) has a round point with small triangular cutting edge for working leather, synthetic leather and other coated materials – never for woven fabric, since the cutting action would sever the weave threads. It is used in industrial sewing machines for leather and synthetic-leather work, where the cutting point produces a clean puncture. Suitable machine classes are found, among others, at Juki (classes ACF, ALS, AMS, APW), Brother (classes BAS -300E, BAS -311A, BAS -311E, BAS -311EL) and Singer (classes 61, 107, 111, 112).
Thinner needle sizes are used, among others, for medium-weight leather for everyday leather goods and saddlery work, and the thicker versions for very thick, firm leather and multi-layer leather joins. As sewing thread, a bonded polyester or nylon thread such as Amann Serabond, Amann Strongbond or Coats Dabond is usually recommended, in a thickness matching the needle size chosen. A cutting point is required here to create clean puncture channels in firm materials.
