How to choose the correct needle for heavy duty lockstitch sewing machine?

The heavy-duty lockstitch sewing machine has the function of synchronous feeding of needle, tooth, and presser foot, which can prevent the sewing material from slipping, its stitches are beautiful and neat. the rotary hook creates two parallel rows of lockstitches. The upper and lower shafts are driven by synchronous toothed belts, the rotating disc adjusts the stitch distance and the lever-type reverse feeding mechanism makes the operation easier. And equipped with a clutch safety device to prevent machine damage caused by overload. When choosing a machine needle, it is important to consider the thickness, hardness, and hardness of the material. The selection of the heavy-duty lockstitch sewing machine needle is very important.

The following is the selection guide for the needlepoint and the machine needle, for reference only:

1) Selection of needlepoint shape: When selecting the shape of the needle blade, the type of leather to be sewn must be considered.thickness, characteristics, stitched parts, whether it is edge seam or piping seam, or decorative seam, and the type of suture used, etc.

Fine decorative seams are characterized by extra large sewing density, which is especially suitable for soft leather. For this purpose, a chisel point must be used. The needle incision made by this type of needle is at right angles to the direction of the seam, so the material between each needle Using more needle points than any other shape allows higher densities (up to 25-30 stitches per hour in practice) and results in durable seams. When using a machine needle with a vertical blade-type needlepoint, the needle incision sewn will be parallel to the direction of the seam. Since there is less material between the needle incisions, the surface is full of holes when there are only less than 20 stitches per hour. The cross-edged needlepoint is suitable for high-density stitch sewing. The vertical-edged needlepoint needs to have a certain length of needle code, that is, the stitches should be spaced as far as possible. They all refer to the sewing machine that is threaded from the side by excitation. If the needle is threaded from the front, the needle cut and seam appearance produced by the longitudinal blade point are the same as those obtained by the chiseled point threaded from the side, and vice versa.

2) Selection of needle specifications

The needle size of the shoemaking sewing machine depends on the thickness of the sewing material. There are three commonly used methods to indicate the size of the needle: "the metric system", "the number system" and "the inch system".Under normal circumstances, small (fine) needles should be used for sewing thin and soft leather materials, and large (coarse) needles should be used for sewing thick and hard leather materials.

From the perspective of stitches selection, thick needles are used for thick threads, and thin needles are used for thin threads, because the inner diameter of the needle hole is proportional to the diameter of the needle shaft, and the thicker the needle shaft, the larger the threading hole, otherwise the needle and thread will not match.

Heavy-duty lockstitch sewing machine is widely used in sewing filter bags, tents, parachutes, seat cushions, sofas, luggage, and other products. The stitches are more beautiful when the needle is selected properly.