Strictly speaking, the alignment between the needle of the sewing machine and the upper and lower bending needles is standard.

For example, machine parts loose or different materials must be treated according to the actual situation of the machine.

When the needle reaches the highest point, the needle tip to the needle plate plane (2 lines, 3 lines 9-10 mm), (4 line left needle 9-10 mm, right needle 8-9 mm), (5 line chain machine needle 7.5-5.8 mm, edge stitch needle 9-10 mm).

When the bending needle and chain line swing to the far left position, the needle at the lowest point is the distance from the needle tip to the machine needle (3 line is 3.5-4 mm), (4 line 2.8-3.1 mm left needle), (5 line 3.5-4 mm), the inclination angle of the bending pin is 3-6 degrees, the gap between them is 0.05 mm, the distance between the 5 thread chain pin and the needle is 2.5-3 mm, and the hook angle is 5-7 degrees.

Positioning of needle and upper needle and upper fork needle

When the upper bending needle and the upper fork slider reach the highest position, the distance between the 2 line fork needle and the needle is 4-4.5 mm. (the 3 line needle tip goes down to the upper bending needle when it contacts the upper bending needle, the distance from the needle tip to the machine needle is 4-4.5 mm), (4 line bending needle pinhole is in the middle of the two machine needle), (5 lines with 3 lines), the distance between the upper bending needle and the lower bending needle is even 0.10 mm.