Double-needle sewing machines and single-needle are mainly used for sewing clothes.
The difference between double-needle and single-needle sewing machines
A single-needle sewing machine is also called a flat car, which has only one track line at a time. A double-needle sewing machine is also called a double-needle car, which has two evenly spaced tracks at a time.
Double-needle sewing machine, as the name suggests, is a sewing machine with two needles, and the effect is that the double threads are juxtaposed and parallel to each other. A pair of trousers uses double needles less than flat lathes, so in the workshop, the matching of flat lathes and double needles is about 5:1, but it is indispensable.
Although a flat car can sometimes replace a double needle, no one is stupid enough to use a flat car to do double needle work in mass production, unless it is a small amount of production. The efficiency of the double needle is high, and the double lines are parallel and neat.
Top quality shirts always feature single-needle stitching. Single-needle seams can look very clean, neat and accurate. Moreover, they’re strong and durable, but the use of this technique increases production costs. It’s very easy to recognise single-needle side seams: you’ll see only one row of stitches in the outer side of the shirt and two rows of stitches inside the shirt. The distance between these rows is very small (in the best cases – only 2-2.5 mm).
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However, some shirts (for instance, Turnbull & Asser ones) may feature single-needle stitching with two rows of stitches outside and only one row inside.
When inspecting a shirt with double-needle (or twin-needle) stitching you will notice two rows of stitches inside and two rows outside; the distance between these rows is usually 4-6 mm. It takes significantly less time and effort to stitch side seams in this way, that’s why most shirts feature twin-needle side seams.
The fabric between these rows of stitches can wrinkle heavily after washing, but I must say that sometimes single-needle stitching doesn’t prevent this problem. If you want to produce a top quality shirt, the single-needle seams must be sewn in a proper way and with the minimal and constant distance between the rows of stitches. Besides, the look of the seams depends on fabrics and ironing too. Single-needle side seams don’t necessarily look better than twin-needle ones.
Moreover, twin-needle stitching sometimes can look better than inferior single-needle stitching (if the distance between the rows of stitches is very small, and the stitch density is high).
It must be added that some producers (for example, Olymp) stitch the side seams in another way. The seams of their shirts aren’t flat, and you can’t notice any rows of stitching outside, but if you look inside the shirt, you’ll see lots of looped stitches sewn by an overlock machine. T-shirts and polo shirts are very often stitched in this way; only the best polo shirts feature single-needle stitching.
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Bonded Thread of Twin Needle Sewing
It is more difficult for the sewing thread to have a good pair of needles. The main problem is that the direction of one of the two needles is reversed, and the sewing thread in the opposite direction will produce the effect of retreat. The sewing thread is generally In the S direction (clockwise), the line that is going in the opposite direction will loosen, knot or even break because of the retreat. Read More: Bonded Thread
To solve the problem of double-needle sewing, we must avoid the problem of unwinding and loosening the strands. If we do not loosen the sewing thread, we can avoid unwinding. When weaving the thread, we must add a low-melting-point thermal fuse inside the thread. After being heated and set, the strands are bonded together as a whole. This non-distributive sewing thread is called bonded sewing thread. When the Bondi twin-needle needles are stitched, the sewing thread is single-stranded. It is the best choice of sewing thread for solving the double needle sewing.
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