The D-5 F needle (needle system D-5) has a square point (45°) 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 Fischbein (classes D, DB, DH, DR), Dave Fischbein Co. (classes DB, DH, DR, E) and Elcu Sud (classes 90 -91).
The available needle sizes are used, among others, 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.
